/******************************************************************************
 *
 * Project:  GeoTIFF Driver
 * Purpose:  Implements translation between GeoTIFF normalized projection
 *           definitions and OpenGIS WKT SRS format.
 * Author:   Frank Warmerdam, warmerdam@pobox.com
 *
 ******************************************************************************
 * Copyright (c) 1999, Frank Warmerdam
 * Copyright (c) 2008-2014, Even Rouault <even dot rouault at spatialys.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 ****************************************************************************/

#include "cpl_port.h"

#include "gt_wkt_srs.h"

#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>

#include <algorithm>
#include <mutex>

#include "cpl_conv.h"
#include "cpl_error.h"
#include "cpl_multiproc.h"
#include "cpl_string.h"
#include "cpl_vsi.h"
#include "gt_citation.h"
#include "gt_wkt_srs_for_gdal.h"
#include "gt_wkt_srs_priv.h"
#include "gtiff.h"
#include "gdal.h"
#include "geokeys.h"
#include "geovalues.h"
#include "ogr_core.h"
#include "ogr_spatialref.h"
#include "ogr_srs_api.h"
#include "ogr_proj_p.h"
#include "tiff.h"
#include "tiffio.h"
#include "tifvsi.h"
#include "xtiffio.h"

#include "proj.h"

static const geokey_t ProjLinearUnitsInterpCorrectGeoKey =
    static_cast<geokey_t>(3059);

#ifndef CT_HotineObliqueMercatorAzimuthCenter
#define CT_HotineObliqueMercatorAzimuthCenter 9815
#endif

#if !defined(GTIFAtof)
#define GTIFAtof CPLAtof
#endif

// To remind myself not to use CPLString in this file!
#define CPLString Please_do_not_use_CPLString_in_this_file

static const char *const papszDatumEquiv[] = {
    "Militar_Geographische_Institut",
    "Militar_Geographische_Institute",
    "World_Geodetic_System_1984",
    "WGS_1984",
    "WGS_72_Transit_Broadcast_Ephemeris",
    "WGS_1972_Transit_Broadcast_Ephemeris",
    "World_Geodetic_System_1972",
    "WGS_1972",
    "European_Terrestrial_Reference_System_89",
    "European_Reference_System_1989",
    "D_North_American_1927",
    "North_American_Datum_1927",  // #6863
    nullptr};

// Older libgeotiff's won't list this.
#ifndef CT_CylindricalEqualArea
#define CT_CylindricalEqualArea 28
#endif

#if LIBGEOTIFF_VERSION < 1700
constexpr geokey_t CoordinateEpochGeoKey = static_cast<geokey_t>(5120);
#endif

// Exists since 8.0.1
#ifndef PROJ_AT_LEAST_VERSION
#define PROJ_COMPUTE_VERSION(maj, min, patch)                                  \
    ((maj)*10000 + (min)*100 + (patch))
#define PROJ_VERSION_NUMBER                                                    \
    PROJ_COMPUTE_VERSION(PROJ_VERSION_MAJOR, PROJ_VERSION_MINOR,               \
                         PROJ_VERSION_PATCH)
#define PROJ_AT_LEAST_VERSION(maj, min, patch)                                 \
    (PROJ_VERSION_NUMBER >= PROJ_COMPUTE_VERSION(maj, min, patch))
#endif

/************************************************************************/
/*                       LibgeotiffOneTimeInit()                        */
/************************************************************************/

static std::mutex oDeleteMutex;

void LibgeotiffOneTimeInit()
{
    std::lock_guard<std::mutex> oLock(oDeleteMutex);

    static bool bOneTimeInitDone = false;

    if (bOneTimeInitDone)
        return;

    bOneTimeInitDone = true;

    // This isn't thread-safe, so better do it now
    XTIFFInitialize();
}

/************************************************************************/
/*                       GTIFToCPLRecyleString()                        */
/*                                                                      */
/*      This changes a string from the libgeotiff heap to the GDAL      */
/*      heap.                                                           */
/************************************************************************/

static void GTIFToCPLRecycleString(char **ppszTarget)

{
    if (*ppszTarget == nullptr)
        return;

    char *pszTempString = CPLStrdup(*ppszTarget);
    GTIFFreeMemory(*ppszTarget);
    *ppszTarget = pszTempString;
}

/************************************************************************/
/*                          WKTMassageDatum()                           */
/*                                                                      */
/*      Massage an EPSG datum name into WMT format.  Also transform     */
/*      specific exception cases into WKT versions.                     */
/************************************************************************/

static void WKTMassageDatum(char **ppszDatum)

{
    char *pszDatum = *ppszDatum;
    if (!pszDatum || pszDatum[0] == '\0')
        return;

    /* -------------------------------------------------------------------- */
    /*      Translate non-alphanumeric values to underscores.               */
    /* -------------------------------------------------------------------- */
    for (int i = 0; pszDatum[i] != '\0'; i++)
    {
        if (pszDatum[i] != '+' && !(pszDatum[i] >= 'A' && pszDatum[i] <= 'Z') &&
            !(pszDatum[i] >= 'a' && pszDatum[i] <= 'z') &&
            !(pszDatum[i] >= '0' && pszDatum[i] <= '9'))
        {
            pszDatum[i] = '_';
        }
    }

    /* -------------------------------------------------------------------- */
    /*      Remove repeated and trailing underscores.                       */
    /* -------------------------------------------------------------------- */
    int j = 0;  // Used after for.
    for (int i = 1; pszDatum[i] != '\0'; i++)
    {
        if (pszDatum[j] == '_' && pszDatum[i] == '_')
            continue;

        pszDatum[++j] = pszDatum[i];
    }
    if (pszDatum[j] == '_')
        pszDatum[j] = '\0';
    else
        pszDatum[j + 1] = '\0';

    /* -------------------------------------------------------------------- */
    /*      Search for datum equivalences.  Specific massaged names get     */
    /*      mapped to OpenGIS specified names.                              */
    /* -------------------------------------------------------------------- */
    for (int i = 0; papszDatumEquiv[i] != nullptr; i += 2)
    {
        if (EQUAL(*ppszDatum, papszDatumEquiv[i]))
        {
            CPLFree(*ppszDatum);
            *ppszDatum = CPLStrdup(papszDatumEquiv[i + 1]);
            return;
        }
    }
}

/************************************************************************/
/*                      GTIFCleanupImageineNames()                      */
/*                                                                      */
/*      Erdas Imagine sometimes emits big copyright messages, and       */
/*      other stuff into citations.  These can be pretty messy when     */
/*      turned into WKT, so we try to trim and clean the strings        */
/*      somewhat.                                                       */
/************************************************************************/

/* For example:
   GTCitationGeoKey (Ascii,215): "IMAGINE GeoTIFF Support\nCopyright 1991 - 2001
   by ERDAS, Inc. All Rights Reserved\n@(#)$RCSfile$ $Revision: 34309 $ $Date:
   2016-05-29 11:29:40 -0700 (Sun, 29 May 2016) $\nProjection Name = UTM\nUnits
   = meters\nGeoTIFF Units = meters"

   GeogCitationGeoKey (Ascii,267): "IMAGINE GeoTIFF Support\nCopyright 1991 -
   2001 by ERDAS, Inc. All Rights Reserved\n@(#)$RCSfile$ $Revision: 34309 $
   $Date: 2016-05-29 11:29:40 -0700 (Sun, 29 May 2016) $\nUnable to match
   Ellipsoid (Datum) to a GeographicTypeGeoKey value\nEllipsoid = Clarke
   1866\nDatum = NAD27 (CONUS)"

   PCSCitationGeoKey (Ascii,214): "IMAGINE GeoTIFF Support\nCopyright 1991 -
   2001 by ERDAS, Inc. All Rights Reserved\n@(#)$RCSfile$ $Revision: 34309 $
   $Date: 2016-05-29 11:29:40 -0700 (Sun, 29 May 2016) $\nUTM Zone
   10N\nEllipsoid = Clarke 1866\nDatum = NAD27 (CONUS)"
*/

static void GTIFCleanupImagineNames(char *pszCitation)

{
    if (strstr(pszCitation, "IMAGINE GeoTIFF") == nullptr)
        return;

    /* -------------------------------------------------------------------- */
    /*      First, we skip past all the copyright, and RCS stuff.  We       */
    /*      assume that this will have a "$" at the end of it all.          */
    /* -------------------------------------------------------------------- */
    char *pszSkip = pszCitation + strlen(pszCitation) - 1;

    for (; pszSkip != pszCitation && *pszSkip != '$'; pszSkip--)
    {
    }

    if (*pszSkip == '$')
        pszSkip++;
    if (*pszSkip == '\n')
        pszSkip++;

    memmove(pszCitation, pszSkip, strlen(pszSkip) + 1);

    /* -------------------------------------------------------------------- */
    /*      Convert any newlines into spaces, they really gum up the        */
    /*      WKT.                                                            */
    /* -------------------------------------------------------------------- */
    for (int i = 0; pszCitation[i] != '\0'; i++)
    {
        if (pszCitation[i] == '\n')
            pszCitation[i] = ' ';
    }
}

#if LIBGEOTIFF_VERSION < 1600

/************************************************************************/
/*                       GDALGTIFKeyGet()                               */
/************************************************************************/

static int GDALGTIFKeyGet(GTIF *hGTIF, geokey_t key, void *pData, int nIndex,
                          int nCount, tagtype_t expected_tagtype)
{
    tagtype_t tagtype = TYPE_UNKNOWN;
    if (!GTIFKeyInfo(hGTIF, key, nullptr, &tagtype))
        return 0;
    if (tagtype != expected_tagtype)
    {
        CPLError(CE_Warning, CPLE_AppDefined,
                 "Expected key %s to be of type %s. Got %s", GTIFKeyName(key),
                 GTIFTypeName(expected_tagtype), GTIFTypeName(tagtype));
        return 0;
    }
    return GTIFKeyGet(hGTIF, key, pData, nIndex, nCount);
}

/************************************************************************/
/*                       GDALGTIFKeyGetASCII()                          */
/************************************************************************/

int GDALGTIFKeyGetASCII(GTIF *hGTIF, geokey_t key, char *szStr, int szStrMaxLen)
{
    return GDALGTIFKeyGet(hGTIF, key, szStr, 0, szStrMaxLen, TYPE_ASCII);
}

/************************************************************************/
/*                       GDALGTIFKeyGetSHORT()                          */
/************************************************************************/

int GDALGTIFKeyGetSHORT(GTIF *hGTIF, geokey_t key, unsigned short *pnVal,
                        int nIndex, int nCount)
{
    return GDALGTIFKeyGet(hGTIF, key, pnVal, nIndex, nCount, TYPE_SHORT);
}

/************************************************************************/
/*                        GDALGTIFKeyGetDOUBLE()                        */
/************************************************************************/

int GDALGTIFKeyGetDOUBLE(GTIF *hGTIF, geokey_t key, double *pdfVal, int nIndex,
                         int nCount)
{
    return GDALGTIFKeyGet(hGTIF, key, pdfVal, nIndex, nCount, TYPE_DOUBLE);
}

#endif

/************************************************************************/
/*                    FillCompoundCRSWithManualVertCS()                 */
/************************************************************************/

static void FillCompoundCRSWithManualVertCS(GTIF *hGTIF,
                                            OGRSpatialReference &oSRS,
                                            const char *pszVertCSName,
                                            int verticalDatum,
                                            int verticalUnits)
{
    /* -------------------------------------------------------------------- */
    /*      Setup VERT_CS with citation if present.                         */
    /* -------------------------------------------------------------------- */
    oSRS.SetNode("COMPD_CS|VERT_CS", pszVertCSName);

    /* -------------------------------------------------------------------- */
    /*      Setup the vertical datum.                                       */
    /* -------------------------------------------------------------------- */
    std::string osVDatumName = "unknown";
    const char *pszVDatumType = "2005";  // CS_VD_GeoidModelDerived

    if (verticalDatum > 0 && verticalDatum != KvUserDefined)
    {
        char szCode[12];
        snprintf(szCode, sizeof(szCode), "%d", verticalDatum);
        auto ctx =
            static_cast<PJ_CONTEXT *>(GTIFGetPROJContext(hGTIF, true, nullptr));
        auto datum = proj_create_from_database(ctx, "EPSG", szCode,
                                               PJ_CATEGORY_DATUM, 0, nullptr);
        if (datum)
        {
            const char *pszName = proj_get_name(datum);
            if (pszName)
            {
                osVDatumName = pszName;
            }
            proj_destroy(datum);
        }
    }

    oSRS.SetNode("COMPD_CS|VERT_CS|VERT_DATUM", osVDatumName.c_str());
    oSRS.GetAttrNode("COMPD_CS|VERT_CS|VERT_DATUM")
        ->AddChild(new OGR_SRSNode(pszVDatumType));
    if (verticalDatum > 0 && verticalDatum != KvUserDefined)
        oSRS.SetAuthority("COMPD_CS|VERT_CS|VERT_DATUM", "EPSG", verticalDatum);

    /* -------------------------------------------------------------------- */
    /*      Set the vertical units.                                         */
    /* -------------------------------------------------------------------- */
    if (verticalUnits > 0 && verticalUnits != KvUserDefined &&
        verticalUnits != 9001)
    {
        char szCode[12];
        snprintf(szCode, sizeof(szCode), "%d", verticalUnits);
        auto ctx =
            static_cast<PJ_CONTEXT *>(GTIFGetPROJContext(hGTIF, true, nullptr));
        const char *pszName = nullptr;
        double dfInMeters = 0.0;
        if (proj_uom_get_info_from_database(ctx, "EPSG", szCode, &pszName,
                                            &dfInMeters, nullptr))
        {
            if (pszName)
                oSRS.SetNode("COMPD_CS|VERT_CS|UNIT", pszName);

            char szInMeters[128] = {};
            CPLsnprintf(szInMeters, sizeof(szInMeters), "%.16g", dfInMeters);
            oSRS.GetAttrNode("COMPD_CS|VERT_CS|UNIT")
                ->AddChild(new OGR_SRSNode(szInMeters));
        }

        oSRS.SetAuthority("COMPD_CS|VERT_CS|UNIT", "EPSG", verticalUnits);
    }
    else
    {
        oSRS.SetNode("COMPD_CS|VERT_CS|UNIT", "metre");
        oSRS.GetAttrNode("COMPD_CS|VERT_CS|UNIT")
            ->AddChild(new OGR_SRSNode("1.0"));
        oSRS.SetAuthority("COMPD_CS|VERT_CS|UNIT", "EPSG", 9001);
    }

    /* -------------------------------------------------------------------- */
    /*      Set the axis and VERT_CS authority.                             */
    /* -------------------------------------------------------------------- */
    oSRS.SetNode("COMPD_CS|VERT_CS|AXIS", "Up");
    oSRS.GetAttrNode("COMPD_CS|VERT_CS|AXIS")->AddChild(new OGR_SRSNode("UP"));
}

/************************************************************************/
/*                    GTIFGetEPSGOfficialName()                         */
/************************************************************************/

static char *GTIFGetEPSGOfficialName(GTIF *hGTIF, PJ_TYPE searchType,
                                     const char *pszName)
{
    char *pszRet = nullptr;
    /* Search in database the corresponding EPSG 'official' name */
    auto ctx =
        static_cast<PJ_CONTEXT *>(GTIFGetPROJContext(hGTIF, true, nullptr));
    auto list = proj_create_from_name(ctx, "EPSG", pszName, &searchType, 1,
                                      false, /* approximate match */
                                      1, nullptr);
    if (list)
    {
        const auto listSize = proj_list_get_count(list);
        if (listSize == 1)
        {
            auto obj = proj_list_get(ctx, list, 0);
            if (obj)
            {
                const char *pszOfficialName = proj_get_name(obj);
                if (pszOfficialName)
                {
                    pszRet = CPLStrdup(pszOfficialName);
                }
            }
            proj_destroy(obj);
        }
        proj_list_destroy(list);
    }
    return pszRet;
}

/************************************************************************/
/*                      GTIFGetOGISDefnAsOSR()                          */
/************************************************************************/

OGRSpatialReferenceH GTIFGetOGISDefnAsOSR(GTIF *hGTIF, GTIFDefn *psDefn)

{
    OGRSpatialReference oSRS;

    LibgeotiffOneTimeInit();

#if LIBGEOTIFF_VERSION >= 1600
    void *projContext = GTIFGetPROJContext(hGTIF, FALSE, nullptr);
#endif

    /* -------------------------------------------------------------------- */
    /*  Handle non-standard coordinate systems where GTModelTypeGeoKey      */
    /*  is not defined, but ProjectedCSTypeGeoKey is defined (ticket #3019) */
    /* -------------------------------------------------------------------- */
    if (psDefn->Model == KvUserDefined && psDefn->PCS != KvUserDefined)
    {
        psDefn->Model = ModelTypeProjected;
    }

    /* ==================================================================== */
    /*      Read keys related to vertical component.                        */
    /* ==================================================================== */
    unsigned short verticalCSType = 0;
    unsigned short verticalDatum = 0;
    unsigned short verticalUnits = 0;

    GDALGTIFKeyGetSHORT(hGTIF, VerticalCSTypeGeoKey, &verticalCSType, 0, 1);
    GDALGTIFKeyGetSHORT(hGTIF, VerticalDatumGeoKey, &verticalDatum, 0, 1);
    GDALGTIFKeyGetSHORT(hGTIF, VerticalUnitsGeoKey, &verticalUnits, 0, 1);

    if (verticalCSType != 0 || verticalDatum != 0 || verticalUnits != 0)
    {
        int versions[3];
        GTIFDirectoryInfo(hGTIF, versions, nullptr);
        // GeoTIFF 1.0
        if (versions[0] == 1 && versions[1] == 1 && versions[2] == 0)
        {
            /* --------------------------------------------------------------------
             */
            /*      The original geotiff specification appears to have */
            /*      misconstrued the EPSG codes 5101 to 5106 to be vertical */
            /*      coordinate system codes, when in fact they are vertical */
            /*      datum codes.  So if these are found in the */
            /*      VerticalCSTypeGeoKey move them to the VerticalDatumGeoKey */
            /*      and insert the "normal" corresponding VerticalCSTypeGeoKey
             */
            /*      value. */
            /* --------------------------------------------------------------------
             */
            if ((verticalCSType >= 5101 && verticalCSType <= 5112) &&
                verticalDatum == 0)
            {
                verticalDatum = verticalCSType;
                verticalCSType = verticalDatum + 600;
            }

            /* --------------------------------------------------------------------
             */
            /*      This addresses another case where the EGM96 Vertical Datum
             * code */
            /*      is misused as a Vertical CS code (#4922). */
            /* --------------------------------------------------------------------
             */
            if (verticalCSType == 5171)
            {
                verticalDatum = 5171;
                verticalCSType = 5773;
            }
        }

        /* --------------------------------------------------------------------
         */
        /*      Somewhat similarly, codes 5001 to 5033 were treated as */
        /*      vertical coordinate systems based on ellipsoidal heights. */
        /*      We use the corresponding geodetic datum as the vertical */
        /*      datum and clear the vertical coordinate system code since */
        /*      there isn't one in EPSG. */
        /* --------------------------------------------------------------------
         */
        if ((verticalCSType >= 5001 && verticalCSType <= 5033) &&
            verticalDatum == 0)
        {
            verticalDatum = verticalCSType + 1000;
            verticalCSType = 0;
        }
    }

    /* -------------------------------------------------------------------- */
    /*      Handle non-standard coordinate systems as LOCAL_CS.             */
    /* -------------------------------------------------------------------- */
    if (psDefn->Model != ModelTypeProjected &&
        psDefn->Model != ModelTypeGeographic &&
        psDefn->Model != ModelTypeGeocentric)
    {
        char szPeStr[2400] = {'\0'};

        /** check if there is a pe string citation key **/
        if (GDALGTIFKeyGetASCII(hGTIF, PCSCitationGeoKey, szPeStr,
                                sizeof(szPeStr)) &&
            strstr(szPeStr, "ESRI PE String = "))
        {
            const char *pszWKT = szPeStr + strlen("ESRI PE String = ");
            oSRS.importFromWkt(pszWKT);

            if (strstr(pszWKT,
                       "PROJCS[\"WGS_1984_Web_Mercator_Auxiliary_Sphere\""))
            {
                oSRS.SetExtension(
                    "PROJCS", "PROJ4",
                    "+proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 "
                    "+x_0=0.0 +y_0=0 +k=1.0 +units=m +nadgrids=@null "
                    "+wktext  +no_defs");  // TODO(schwehr): Why 2 spaces?
            }

            return OGRSpatialReference::ToHandle(oSRS.Clone());
        }
        else
        {
            char *pszUnitsName = nullptr;
            char szPCSName[300] = {'\0'};
            int nKeyCount = 0;
            int anVersion[3] = {0};

            GTIFDirectoryInfo(hGTIF, anVersion, &nKeyCount);

            if (nKeyCount > 0)  // Use LOCAL_CS if we have any geokeys at all.
            {
                // Handle citation.
                strcpy(szPCSName, "unnamed");
                if (!GDALGTIFKeyGetASCII(hGTIF, GTCitationGeoKey, szPCSName,
                                         sizeof(szPCSName)))
                    GDALGTIFKeyGetASCII(hGTIF, GeogCitationGeoKey, szPCSName,
                                        sizeof(szPCSName));

                GTIFCleanupImagineNames(szPCSName);
                oSRS.SetLocalCS(szPCSName);

                // Handle units
                if (psDefn->UOMLength != KvUserDefined)
                {
#if LIBGEOTIFF_VERSION >= 1600
                    GTIFGetUOMLengthInfoEx(projContext,
#else
                    GTIFGetUOMLengthInfo(
#endif
                                           psDefn->UOMLength, &pszUnitsName,
                                           nullptr);
                }

                if (pszUnitsName != nullptr)
                {
                    char szUOMLength[12];
                    snprintf(szUOMLength, sizeof(szUOMLength), "%d",
                             psDefn->UOMLength);
                    oSRS.SetTargetLinearUnits(nullptr, pszUnitsName,
                                              psDefn->UOMLengthInMeters, "EPSG",
                                              szUOMLength);
                }
                else
                    oSRS.SetLinearUnits("unknown", psDefn->UOMLengthInMeters);

                if (verticalUnits != 0)
                {
                    char szVertCSCitation[2048] = {0};
                    if (GDALGTIFKeyGetASCII(hGTIF, VerticalCitationGeoKey,
                                            szVertCSCitation,
                                            sizeof(szVertCSCitation)))
                    {
                        if (STARTS_WITH_CI(szVertCSCitation, "VCS Name = "))
                        {
                            memmove(szVertCSCitation,
                                    szVertCSCitation + strlen("VCS Name = "),
                                    strlen(szVertCSCitation +
                                           strlen("VCS Name = ")) +
                                        1);
                            char *pszPipeChar = strchr(szVertCSCitation, '|');
                            if (pszPipeChar)
                                *pszPipeChar = '\0';
                        }
                    }
                    else
                    {
                        strcpy(szVertCSCitation, "unknown");
                    }

                    const char *pszHorizontalName = oSRS.GetName();
                    const std::string osHorizontalName(
                        pszHorizontalName ? pszHorizontalName : "unnamed");
                    /* --------------------------------------------------------------------
                     */
                    /*      Promote to being a compound coordinate system. */
                    /* --------------------------------------------------------------------
                     */
                    OGR_SRSNode *poOldRoot = oSRS.GetRoot()->Clone();

                    oSRS.Clear();

                    /* --------------------------------------------------------------------
                     */
                    /*      Set COMPD_CS name. */
                    /* --------------------------------------------------------------------
                     */
                    char szCTString[512];
                    szCTString[0] = '\0';
                    if (GDALGTIFKeyGetASCII(hGTIF, GTCitationGeoKey, szCTString,
                                            sizeof(szCTString)) &&
                        strstr(szCTString, " = ") == nullptr)
                    {
                        oSRS.SetNode("COMPD_CS", szCTString);
                    }
                    else
                    {
                        oSRS.SetNode("COMPD_CS", (osHorizontalName + " + " +
                                                  szVertCSCitation)
                                                     .c_str());
                    }

                    oSRS.GetRoot()->AddChild(poOldRoot);

                    FillCompoundCRSWithManualVertCS(
                        hGTIF, oSRS, szVertCSCitation, verticalDatum,
                        verticalUnits);
                }

                GTIFFreeMemory(pszUnitsName);
            }
            return OGRSpatialReference::ToHandle(oSRS.Clone());
        }
    }

    /* -------------------------------------------------------------------- */
    /*      Handle Geocentric coordinate systems.                           */
    /* -------------------------------------------------------------------- */
    if (psDefn->Model == ModelTypeGeocentric)
    {
        char szName[300] = {'\0'};

        strcpy(szName, "unnamed");
        if (!GDALGTIFKeyGetASCII(hGTIF, GTCitationGeoKey, szName,
                                 sizeof(szName)))
            GDALGTIFKeyGetASCII(hGTIF, GeogCitationGeoKey, szName,
                                sizeof(szName));

        oSRS.SetGeocCS(szName);

        char *pszUnitsName = nullptr;

        if (psDefn->UOMLength != KvUserDefined)
        {
#if LIBGEOTIFF_VERSION >= 1600
            GTIFGetUOMLengthInfoEx(projContext,
#else
            GTIFGetUOMLengthInfo(
#endif
                                   psDefn->UOMLength, &pszUnitsName, nullptr);
        }

        if (pszUnitsName != nullptr)
        {
            char szUOMLength[12];
            snprintf(szUOMLength, sizeof(szUOMLength), "%d", psDefn->UOMLength);
            oSRS.SetTargetLinearUnits(nullptr, pszUnitsName,
                                      psDefn->UOMLengthInMeters, "EPSG",
                                      szUOMLength);
        }
        else
            oSRS.SetLinearUnits("unknown", psDefn->UOMLengthInMeters);

        GTIFFreeMemory(pszUnitsName);
    }

    /* -------------------------------------------------------------------- */
    /*      #3901: In libgeotiff 1.3.0 and earlier we incorrectly           */
    /*      interpreted linear projection parameter geokeys (false          */
    /*      easting/northing) as being in meters instead of the             */
    /*      coordinate system of the file.   The following code attempts    */
    /*      to provide mechanisms for fixing the issue if we are linked     */
    /*      with an older version of libgeotiff.                            */
    /* -------------------------------------------------------------------- */
    const char *pszLinearUnits =
        CPLGetConfigOption("GTIFF_LINEAR_UNITS", "DEFAULT");

    /* -------------------------------------------------------------------- */
    /*      #3901: If folks have broken GeoTIFF files generated with        */
    /*      older versions of GDAL+libgeotiff, then they may need a         */
    /*      hack to allow them to be read properly.  This is that           */
    /*      hack.  We basically try to undue the conversion applied by      */
    /*      libgeotiff to meters (or above) to simulate the old             */
    /*      behavior.                                                       */
    /* -------------------------------------------------------------------- */
    unsigned short bLinearUnitsMarkedCorrect = FALSE;

    GDALGTIFKeyGetSHORT(hGTIF, ProjLinearUnitsInterpCorrectGeoKey,
                        &bLinearUnitsMarkedCorrect, 0, 1);

    if (EQUAL(pszLinearUnits, "BROKEN") &&
        psDefn->Projection == KvUserDefined && !bLinearUnitsMarkedCorrect)
    {
        for (int iParam = 0; iParam < psDefn->nParms; iParam++)
        {
            switch (psDefn->ProjParmId[iParam])
            {
                case ProjFalseEastingGeoKey:
                case ProjFalseNorthingGeoKey:
                case ProjFalseOriginEastingGeoKey:
                case ProjFalseOriginNorthingGeoKey:
                case ProjCenterEastingGeoKey:
                case ProjCenterNorthingGeoKey:
                    if (psDefn->UOMLengthInMeters != 0 &&
                        psDefn->UOMLengthInMeters != 1.0)
                    {
                        psDefn->ProjParm[iParam] /= psDefn->UOMLengthInMeters;
                        CPLDebug(
                            "GTIFF",
                            "Converting geokey to accommodate old broken file "
                            "due to GTIFF_LINEAR_UNITS=BROKEN setting.");
                    }
                    break;

                default:
                    break;
            }
        }
    }

    /* -------------------------------------------------------------------- */
    /*      If this is a projected SRS we set the PROJCS keyword first      */
    /*      to ensure that the GEOGCS will be a child.                      */
    /* -------------------------------------------------------------------- */
    OGRBoolean linearUnitIsSet = FALSE;
    if (psDefn->Model == ModelTypeProjected)
    {
        char szCTString[512] = {'\0'};
        if (psDefn->PCS != KvUserDefined)
        {
            char *pszPCSName = nullptr;

#if LIBGEOTIFF_VERSION >= 1600
            GTIFGetPCSInfoEx(projContext,
#else
            GTIFGetPCSInfo(
#endif
                             psDefn->PCS, &pszPCSName, nullptr, nullptr,
                             nullptr);

            oSRS.SetProjCS(pszPCSName ? pszPCSName : "unnamed");
            if (pszPCSName)
                GTIFFreeMemory(pszPCSName);

            oSRS.SetLinearUnits("unknown", 1.0);
        }
        else
        {
            bool bTryGTCitationGeoKey = true;
            if (GDALGTIFKeyGetASCII(hGTIF, PCSCitationGeoKey, szCTString,
                                    sizeof(szCTString)))
            {
                bTryGTCitationGeoKey = false;
                if (!SetCitationToSRS(hGTIF, szCTString, sizeof(szCTString),
                                      PCSCitationGeoKey, &oSRS,
                                      &linearUnitIsSet))
                {
                    if (!STARTS_WITH_CI(szCTString, "LUnits = "))
                    {
                        oSRS.SetProjCS(szCTString);
                        oSRS.SetLinearUnits("unknown", 1.0);
                    }
                    else
                    {
                        bTryGTCitationGeoKey = true;
                    }
                }
            }

            if (bTryGTCitationGeoKey)
            {
                if (GDALGTIFKeyGetASCII(hGTIF, GTCitationGeoKey, szCTString,
                                        sizeof(szCTString)) &&
                    !SetCitationToSRS(hGTIF, szCTString, sizeof(szCTString),
                                      GTCitationGeoKey, &oSRS,
                                      &linearUnitIsSet))
                {
                    oSRS.SetNode("PROJCS", szCTString);
                    oSRS.SetLinearUnits("unknown", 1.0);
                }
                else
                {
                    oSRS.SetNode("PROJCS", "unnamed");
                    oSRS.SetLinearUnits("unknown", 1.0);
                }
            }
        }

        /* Handle ESRI/Erdas style state plane and UTM in citation key */
        if (CheckCitationKeyForStatePlaneUTM(hGTIF, psDefn, &oSRS,
                                             &linearUnitIsSet))
        {
            return OGRSpatialReference::ToHandle(oSRS.Clone());
        }

        /* Handle ESRI PE string in citation */
        szCTString[0] = '\0';
        if (GDALGTIFKeyGetASCII(hGTIF, GTCitationGeoKey, szCTString,
                                sizeof(szCTString)))
            SetCitationToSRS(hGTIF, szCTString, sizeof(szCTString),
                             GTCitationGeoKey, &oSRS, &linearUnitIsSet);
    }

    /* ==================================================================== */
    /*      Setup the GeogCS                                                */
    /* ==================================================================== */
    char *pszGeogName = nullptr;
    char *pszDatumName = nullptr;
    char *pszPMName = nullptr;
    char *pszSpheroidName = nullptr;
    char *pszAngularUnits = nullptr;
    char szGCSName[512] = {'\0'};

    if (!
#if LIBGEOTIFF_VERSION >= 1600
        GTIFGetGCSInfoEx(projContext,
#else
        GTIFGetGCSInfo(
#endif
                         psDefn->GCS, &pszGeogName, nullptr, nullptr,
                         nullptr) &&
        GDALGTIFKeyGetASCII(hGTIF, GeogCitationGeoKey, szGCSName,
                            sizeof(szGCSName)))
    {
        GetGeogCSFromCitation(szGCSName, sizeof(szGCSName), GeogCitationGeoKey,
                              &pszGeogName, &pszDatumName, &pszPMName,
                              &pszSpheroidName, &pszAngularUnits);
    }
    else
    {
        GTIFToCPLRecycleString(&pszGeogName);
    }

    if (pszGeogName && STARTS_WITH(pszGeogName, "GCS_"))
    {
        // Morph from potential ESRI name
        char *pszOfficialName = GTIFGetEPSGOfficialName(
            hGTIF, PJ_TYPE_GEOGRAPHIC_2D_CRS, pszGeogName);
        if (pszOfficialName)
        {
            CPLFree(pszGeogName);
            pszGeogName = pszOfficialName;
        }
    }

    if (pszDatumName && strchr(pszDatumName, '_'))
    {
        // Morph from potential ESRI name
        char *pszOfficialName = GTIFGetEPSGOfficialName(
            hGTIF, PJ_TYPE_GEODETIC_REFERENCE_FRAME, pszDatumName);
        if (pszOfficialName)
        {
            CPLFree(pszDatumName);
            pszDatumName = pszOfficialName;
        }
    }

    if (pszSpheroidName && strchr(pszSpheroidName, '_'))
    {
        // Morph from potential ESRI name
        char *pszOfficialName =
            GTIFGetEPSGOfficialName(hGTIF, PJ_TYPE_ELLIPSOID, pszSpheroidName);
        if (pszOfficialName)
        {
            CPLFree(pszSpheroidName);
            pszSpheroidName = pszOfficialName;
        }
    }

    if (!pszDatumName)
    {
#if LIBGEOTIFF_VERSION >= 1600
        GTIFGetDatumInfoEx(projContext,
#else
        GTIFGetDatumInfo(
#endif
                           psDefn->Datum, &pszDatumName, nullptr);
        GTIFToCPLRecycleString(&pszDatumName);
    }

    double dfSemiMajor = 0.0;
    double dfInvFlattening = 0.0;
    if (!pszSpheroidName)
    {
#if LIBGEOTIFF_VERSION >= 1600
        GTIFGetEllipsoidInfoEx(projContext,
#else
        GTIFGetEllipsoidInfo(
#endif
                               psDefn->Ellipsoid, &pszSpheroidName, nullptr,
                               nullptr);
        GTIFToCPLRecycleString(&pszSpheroidName);
    }
    else
    {
        CPL_IGNORE_RET_VAL(GDALGTIFKeyGetDOUBLE(hGTIF, GeogSemiMajorAxisGeoKey,
                                                &(psDefn->SemiMajor), 0, 1));
        CPL_IGNORE_RET_VAL(GDALGTIFKeyGetDOUBLE(hGTIF, GeogInvFlatteningGeoKey,
                                                &dfInvFlattening, 0, 1));
        if (std::isinf(dfInvFlattening))
        {
            // Deal with the non-nominal case of
            // https://github.com/OSGeo/PROJ/issues/2317
            dfInvFlattening = 0;
        }
    }
    if (!pszPMName)
    {
#if LIBGEOTIFF_VERSION >= 1600
        GTIFGetPMInfoEx(projContext,
#else
        GTIFGetPMInfo(
#endif
                        psDefn->PM, &pszPMName, nullptr);
        GTIFToCPLRecycleString(&pszPMName);
    }
    else
    {
        CPL_IGNORE_RET_VAL(
            GDALGTIFKeyGetDOUBLE(hGTIF, GeogPrimeMeridianLongGeoKey,
                                 &(psDefn->PMLongToGreenwich), 0, 1));
    }

    if (!pszAngularUnits)
    {
#if LIBGEOTIFF_VERSION >= 1600
        GTIFGetUOMAngleInfoEx(projContext,
#else
        GTIFGetUOMAngleInfo(
#endif
                              psDefn->UOMAngle, &pszAngularUnits,
                              &psDefn->UOMAngleInDegrees);
        if (pszAngularUnits == nullptr)
            pszAngularUnits = CPLStrdup("unknown");
        else
            GTIFToCPLRecycleString(&pszAngularUnits);
    }
    else
    {
        double dfRadians = 0.0;
        if (GDALGTIFKeyGetDOUBLE(hGTIF, GeogAngularUnitSizeGeoKey, &dfRadians,
                                 0, 1))
        {
            psDefn->UOMAngleInDegrees = dfRadians / CPLAtof(SRS_UA_DEGREE_CONV);
        }
    }

    // Avoid later division by zero.
    if (psDefn->UOMAngleInDegrees == 0)
    {
        CPLError(CE_Warning, CPLE_AppDefined,
                 "Invalid value for GeogAngularUnitSizeGeoKey.");
        psDefn->UOMAngleInDegrees = 1;
    }

    dfSemiMajor = psDefn->SemiMajor;
    if (dfSemiMajor == 0.0)
    {
        CPLFree(pszSpheroidName);
        pszSpheroidName = CPLStrdup("unretrievable - using WGS84");
        dfSemiMajor = SRS_WGS84_SEMIMAJOR;
        dfInvFlattening = SRS_WGS84_INVFLATTENING;
    }
    else if (dfInvFlattening == 0.0 &&
             ((psDefn->SemiMinor / psDefn->SemiMajor) < 0.99999999999999999 ||
              (psDefn->SemiMinor / psDefn->SemiMajor) > 1.00000000000000001))
    {
        dfInvFlattening =
            OSRCalcInvFlattening(psDefn->SemiMajor, psDefn->SemiMinor);

        /* Take official inverse flattening definition in the WGS84 case */
        if (fabs(dfSemiMajor - SRS_WGS84_SEMIMAJOR) < 1e-10 &&
            fabs(dfInvFlattening - SRS_WGS84_INVFLATTENING) < 1e-10)
            dfInvFlattening = SRS_WGS84_INVFLATTENING;
    }
    if (!pszGeogName || strlen(pszGeogName) == 0)
    {
        CPLFree(pszGeogName);
        pszGeogName = CPLStrdup(pszDatumName ? pszDatumName : "unknown");
    }

    oSRS.SetGeogCS(pszGeogName, pszDatumName, pszSpheroidName, dfSemiMajor,
                   dfInvFlattening, pszPMName, psDefn->PMLongToGreenwich,
                   pszAngularUnits,
                   psDefn->UOMAngleInDegrees * CPLAtof(SRS_UA_DEGREE_CONV));

    bool bGeog3DCRS = false;
    bool bSetDatumEllipsoidCode = true;
    bool bHasWarnedInconsistentGeogCRSEPSG = false;
    {
        const int nGCS = psDefn->GCS;
        if (nGCS != KvUserDefined && nGCS > 0 &&
            psDefn->Model != ModelTypeGeocentric)
        {
            OGRSpatialReference oSRSGeog;
            const bool bGCSCodeValid =
                oSRSGeog.importFromEPSG(nGCS) == OGRERR_NONE;

            const std::string osGTiffSRSSource =
                CPLGetConfigOption("GTIFF_SRS_SOURCE", "");

            // GeoTIFF 1.0 might put a Geographic 3D code in GeodeticCRSGeoKey
            bool bTryCompareToEPSG = oSRSGeog.GetAxesCount() == 2;

            if (psDefn->Datum != KvUserDefined)
            {
                char szCode[12];
                snprintf(szCode, sizeof(szCode), "%d", psDefn->Datum);
                auto ctx = static_cast<PJ_CONTEXT *>(
                    GTIFGetPROJContext(hGTIF, true, nullptr));
                auto datum = proj_create_from_database(
                    ctx, "EPSG", szCode, PJ_CATEGORY_DATUM, 0, nullptr);
                if (datum)
                {
                    if (proj_get_type(datum) ==
                        PJ_TYPE_DYNAMIC_GEODETIC_REFERENCE_FRAME)
                    {
                        // Current PROJ versions will not manage to
                        // consider a CRS with a regular datum and another one
                        // with a dynamic datum as being equivalent.
                        bTryCompareToEPSG = false;
                    }
                    proj_destroy(datum);
                }
            }

            if (bTryCompareToEPSG && !oSRSGeog.IsSameGeogCS(&oSRS) &&
                osGTiffSRSSource.empty())
            {
                // See https://github.com/OSGeo/gdal/issues/5399
                // where a file has inconsistent GeogSemiMinorAxisGeoKey /
                // GeogInvFlatteningGeoKey values, which cause its datum to be
                // considered as non-equivalent to the EPSG one.
                CPLError(
                    CE_Warning, CPLE_AppDefined,
                    "The definition of geographic CRS EPSG:%d got from GeoTIFF "
                    "keys "
                    "is not the same as the one from the EPSG registry, "
                    "which may cause issues during reprojection operations. "
                    "Set GTIFF_SRS_SOURCE configuration option to EPSG to "
                    "use official parameters (overriding the ones from GeoTIFF "
                    "keys), "
                    "or to GEOKEYS to use custom values from GeoTIFF keys "
                    "and drop the EPSG code.",
                    nGCS);
                bHasWarnedInconsistentGeogCRSEPSG = true;
            }
            if (EQUAL(osGTiffSRSSource.c_str(), "EPSG"))
            {
                oSRS.CopyGeogCSFrom(&oSRSGeog);
            }
            else if (osGTiffSRSSource.empty() && oSRSGeog.IsDynamic() &&
                     psDefn->Model == ModelTypeGeographic)
            {
                // We should perhaps be more careful and detect overrides
                // of geokeys...
                oSRS = oSRSGeog;
                bSetDatumEllipsoidCode = false;
            }
            else if (bGCSCodeValid && osGTiffSRSSource.empty())
            {
                oSRS.SetAuthority("GEOGCS", "EPSG", nGCS);
            }
            else
            {
                bSetDatumEllipsoidCode = false;
            }

            int nVertSRSCode = verticalCSType;
            if (verticalDatum == 6030 && nGCS == 4326)  // DatumE_WGS84
            {
                nVertSRSCode = 4979;
            }

            // Try to reconstruct a Geographic3D CRS from the
            // GeodeticCRSGeoKey and the VerticalGeoKey, when they are
            // consistent
            if (nVertSRSCode > 0 && nVertSRSCode != KvUserDefined)
            {
                OGRSpatialReference oTmpVertSRS;
                if (oSRSGeog.IsGeographic() && oSRSGeog.GetAxesCount() == 2 &&
                    oTmpVertSRS.importFromEPSG(nVertSRSCode) == OGRERR_NONE &&
                    oTmpVertSRS.IsGeographic() &&
                    oTmpVertSRS.GetAxesCount() == 3)
                {
                    const char *pszTmpCode =
                        oSRSGeog.GetAuthorityCode("GEOGCS|DATUM");
                    const char *pszTmpVertCode =
                        oTmpVertSRS.GetAuthorityCode("GEOGCS|DATUM");
                    if (pszTmpCode && pszTmpVertCode &&
                        atoi(pszTmpCode) == atoi(pszTmpVertCode))
                    {
                        verticalCSType = 0;
                        verticalDatum = 0;
                        verticalUnits = 0;
                        oSRS.CopyGeogCSFrom(&oTmpVertSRS);
                        bSetDatumEllipsoidCode = false;
                        bGeog3DCRS = true;
                    }
                }
            }
        }
    }
    if (bSetDatumEllipsoidCode)
    {
        if (psDefn->Datum != KvUserDefined)
            oSRS.SetAuthority("DATUM", "EPSG", psDefn->Datum);

        if (psDefn->Ellipsoid != KvUserDefined)
            oSRS.SetAuthority("SPHEROID", "EPSG", psDefn->Ellipsoid);
    }

    CPLFree(pszGeogName);
    CPLFree(pszDatumName);
    CPLFree(pszSpheroidName);
    CPLFree(pszPMName);
    CPLFree(pszAngularUnits);

    /* -------------------------------------------------------------------- */
    /*      Set projection units if not yet done                            */
    /* -------------------------------------------------------------------- */
    if (psDefn->Model == ModelTypeProjected && !linearUnitIsSet)
    {
        char *pszUnitsName = nullptr;

        if (psDefn->UOMLength != KvUserDefined)
        {
#if LIBGEOTIFF_VERSION >= 1600
            GTIFGetUOMLengthInfoEx(projContext,
#else
            GTIFGetUOMLengthInfo(
#endif
                                   psDefn->UOMLength, &pszUnitsName, nullptr);
        }

        if (pszUnitsName != nullptr)
        {
            char szUOMLength[12];
            snprintf(szUOMLength, sizeof(szUOMLength), "%d", psDefn->UOMLength);
            oSRS.SetTargetLinearUnits(nullptr, pszUnitsName,
                                      psDefn->UOMLengthInMeters, "EPSG",
                                      szUOMLength);
        }
        else
            oSRS.SetLinearUnits("unknown", psDefn->UOMLengthInMeters);

        GTIFFreeMemory(pszUnitsName);
    }

    /* ==================================================================== */
    /*      Try to import PROJCS from ProjectedCSTypeGeoKey if we           */
    /*      have essentially only it. We could relax a bit the constraints  */
    /*      but that should do for now. This may mask shortcomings in the   */
    /*      libgeotiff GTIFGetDefn() function.                              */
    /* ==================================================================== */
    unsigned short tmp = 0;
    bool bGotFromEPSG = false;
    if (psDefn->Model == ModelTypeProjected && psDefn->PCS != KvUserDefined &&
        GDALGTIFKeyGetSHORT(hGTIF, ProjectionGeoKey, &tmp, 0, 1) == 0 &&
        GDALGTIFKeyGetSHORT(hGTIF, ProjCoordTransGeoKey, &tmp, 0, 1) == 0 &&
        GDALGTIFKeyGetSHORT(hGTIF, GeographicTypeGeoKey, &tmp, 0, 1) == 0 &&
        GDALGTIFKeyGetSHORT(hGTIF, GeogGeodeticDatumGeoKey, &tmp, 0, 1) == 0 &&
        GDALGTIFKeyGetSHORT(hGTIF, GeogEllipsoidGeoKey, &tmp, 0, 1) == 0 &&
        CPLTestBool(CPLGetConfigOption("GTIFF_IMPORT_FROM_EPSG", "YES")))
    {
        // Save error state as importFromEPSGA() will call CPLReset()
        CPLErrorNum errNo = CPLGetLastErrorNo();
        CPLErr eErr = CPLGetLastErrorType();
        const char *pszTmp = CPLGetLastErrorMsg();
        char *pszLastErrorMsg = CPLStrdup(pszTmp ? pszTmp : "");
        CPLPushErrorHandler(CPLQuietErrorHandler);
        OGRSpatialReference oSRSTmp;
        OGRErr eImportErr = oSRSTmp.importFromEPSG(psDefn->PCS);
        CPLPopErrorHandler();
        // Restore error state
        CPLErrorSetState(eErr, errNo, pszLastErrorMsg);
        CPLFree(pszLastErrorMsg);
        bGotFromEPSG = eImportErr == OGRERR_NONE;

        if (bGotFromEPSG)
        {
            // See #6210. In case there's an overridden linear units, take it
            // into account
            const char *pszUnitsName = nullptr;
            double dfUOMLengthInMeters = oSRS.GetLinearUnits(&pszUnitsName);
            // Non exact comparison, as there's a slight difference between
            // the evaluation of US Survey foot hardcoded in geo_normalize.c to
            // 12.0 / 39.37, and the corresponding value returned by
            // PROJ >= 6.0.0 and <= 7.0.0 for EPSG:9003
            if (fabs(dfUOMLengthInMeters - oSRSTmp.GetLinearUnits(nullptr)) >
                1e-15 * dfUOMLengthInMeters)
            {
                CPLDebug("GTiff", "Modify EPSG:%d to have %s linear units...",
                         psDefn->PCS, pszUnitsName ? pszUnitsName : "unknown");

                const char *pszUnitAuthorityCode =
                    oSRS.GetAuthorityCode("PROJCS|UNIT");
                const char *pszUnitAuthorityName =
                    oSRS.GetAuthorityName("PROJCS|UNIT");

                if (pszUnitsName)
                    oSRSTmp.SetLinearUnitsAndUpdateParameters(
                        pszUnitsName, dfUOMLengthInMeters, pszUnitAuthorityCode,
                        pszUnitAuthorityName);
            }

            if (bGeog3DCRS)
            {
                oSRSTmp.CopyGeogCSFrom(&oSRS);
                oSRSTmp.UpdateCoordinateSystemFromGeogCRS();
            }
            oSRS = oSRSTmp;
        }
    }

#if !defined(GEO_NORMALIZE_DISABLE_TOWGS84)
    if (psDefn->TOWGS84Count > 0 && bGotFromEPSG &&
        CPLTestBool(CPLGetConfigOption("OSR_STRIP_TOWGS84", "YES")))
    {
        CPLDebug("OSR", "TOWGS84 information has been removed. "
                        "It can be kept by setting the OSR_STRIP_TOWGS84 "
                        "configuration option to NO");
    }
    else if (psDefn->TOWGS84Count > 0 &&
             (!bGotFromEPSG ||
              !CPLTestBool(CPLGetConfigOption("OSR_STRIP_TOWGS84", "YES"))))
    {
        if (bGotFromEPSG)
        {
            double adfTOWGS84[7] = {0.0};
            CPL_IGNORE_RET_VAL(oSRS.GetTOWGS84(adfTOWGS84));
            bool bSame = true;
            for (int i = 0; i < 7; i++)
            {
                if (fabs(adfTOWGS84[i] - psDefn->TOWGS84[i]) > 1e-5)
                {
                    bSame = false;
                    break;
                }
            }
            if (!bSame)
            {
                CPLDebug("GTiff",
                         "Modify EPSG:%d to have "
                         "TOWGS84=%f,%f,%f,%f,%f,%f,%f "
                         "coming from GeogTOWGS84GeoKey, instead of "
                         "%f,%f,%f,%f,%f,%f,%f coming from EPSG",
                         psDefn->PCS, psDefn->TOWGS84[0], psDefn->TOWGS84[1],
                         psDefn->TOWGS84[2], psDefn->TOWGS84[3],
                         psDefn->TOWGS84[4], psDefn->TOWGS84[5],
                         psDefn->TOWGS84[6], adfTOWGS84[0], adfTOWGS84[1],
                         adfTOWGS84[2], adfTOWGS84[3], adfTOWGS84[4],
                         adfTOWGS84[5], adfTOWGS84[6]);
            }
        }

        oSRS.SetTOWGS84(psDefn->TOWGS84[0], psDefn->TOWGS84[1],
                        psDefn->TOWGS84[2], psDefn->TOWGS84[3],
                        psDefn->TOWGS84[4], psDefn->TOWGS84[5],
                        psDefn->TOWGS84[6]);
    }
#endif

    /* ==================================================================== */
    /*      Handle projection parameters.                                   */
    /* ==================================================================== */
    if (psDefn->Model == ModelTypeProjected && !bGotFromEPSG)
    {
        /* --------------------------------------------------------------------
         */
        /*      Make a local copy of params, and convert back into the */
        /*      angular units of the GEOGCS and the linear units of the */
        /*      projection. */
        /* --------------------------------------------------------------------
         */
        double adfParam[10] = {0.0};
        int i = 0;  // Used after for.

        for (; i < std::min(10, psDefn->nParms); i++)
            adfParam[i] = psDefn->ProjParm[i];

        for (; i < 10; i++)
            adfParam[i] = 0.0;

        /* --------------------------------------------------------------------
         */
        /*      Translation the fundamental projection. */
        /* --------------------------------------------------------------------
         */
        switch (psDefn->CTProjection)
        {
            case CT_TransverseMercator:
                oSRS.SetTM(adfParam[0], adfParam[1], adfParam[4], adfParam[5],
                           adfParam[6]);
                break;

            case CT_TransvMercator_SouthOriented:
                oSRS.SetTMSO(adfParam[0], adfParam[1], adfParam[4], adfParam[5],
                             adfParam[6]);
                break;

            case CT_Mercator:
                // If a lat_ts was specified use 2SP, otherwise use 1SP.
                if (psDefn->ProjParmId[2] == ProjStdParallel1GeoKey)
                {
                    if (psDefn->ProjParmId[4] == ProjScaleAtNatOriginGeoKey)
                        CPLError(CE_Warning, CPLE_AppDefined,
                                 "Mercator projection should not define "
                                 "both StdParallel1 and ScaleAtNatOrigin.  "
                                 "Using StdParallel1 and ignoring "
                                 "ScaleAtNatOrigin.");
                    oSRS.SetMercator2SP(adfParam[2], adfParam[0], adfParam[1],
                                        adfParam[5], adfParam[6]);
                }
                else
                    oSRS.SetMercator(adfParam[0], adfParam[1], adfParam[4],
                                     adfParam[5], adfParam[6]);

                // Override hack for google mercator.
                if (psDefn->Projection == 1024 || psDefn->Projection == 9841)
                {
                    oSRS.SetExtension(
                        "PROJCS", "PROJ4",
                        "+proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 "
                        "+lon_0=0.0 "
                        "+x_0=0.0 +y_0=0 +k=1.0 +units=m +nadgrids=@null "
                        "+wktext  +no_defs");  // TODO(schwehr): Why 2 spaces?
                }
                break;

            case CT_ObliqueStereographic:
                oSRS.SetOS(adfParam[0], adfParam[1], adfParam[4], adfParam[5],
                           adfParam[6]);
                break;

            case CT_Stereographic:
                oSRS.SetStereographic(adfParam[0], adfParam[1], adfParam[4],
                                      adfParam[5], adfParam[6]);
                break;

            case CT_ObliqueMercator:  // Hotine.
                oSRS.SetHOM(adfParam[0], adfParam[1], adfParam[2], adfParam[3],
                            adfParam[4], adfParam[5], adfParam[6]);
                break;

            case CT_HotineObliqueMercatorAzimuthCenter:
                oSRS.SetHOMAC(adfParam[0], adfParam[1], adfParam[2],
                              adfParam[3], adfParam[4], adfParam[5],
                              adfParam[6]);
                break;

            case CT_ObliqueMercator_Laborde:
                oSRS.SetLOM(adfParam[0], adfParam[1], adfParam[2], adfParam[4],
                            adfParam[5], adfParam[6]);
                break;

            case CT_EquidistantConic:
                oSRS.SetEC(adfParam[0], adfParam[1], adfParam[2], adfParam[3],
                           adfParam[5], adfParam[6]);
                break;

            case CT_CassiniSoldner:
                oSRS.SetCS(adfParam[0], adfParam[1], adfParam[5], adfParam[6]);
                break;

            case CT_Polyconic:
                oSRS.SetPolyconic(adfParam[0], adfParam[1], adfParam[5],
                                  adfParam[6]);
                break;

            case CT_AzimuthalEquidistant:
                oSRS.SetAE(adfParam[0], adfParam[1], adfParam[5], adfParam[6]);
                break;

            case CT_MillerCylindrical:
                oSRS.SetMC(adfParam[0], adfParam[1], adfParam[5], adfParam[6]);
                break;

            case CT_Equirectangular:
                oSRS.SetEquirectangular2(adfParam[0], adfParam[1], adfParam[2],
                                         adfParam[5], adfParam[6]);
                break;

            case CT_Gnomonic:
                oSRS.SetGnomonic(adfParam[0], adfParam[1], adfParam[5],
                                 adfParam[6]);
                break;

            case CT_LambertAzimEqualArea:
                oSRS.SetLAEA(adfParam[0], adfParam[1], adfParam[5],
                             adfParam[6]);
                break;

            case CT_Orthographic:
                oSRS.SetOrthographic(adfParam[0], adfParam[1], adfParam[5],
                                     adfParam[6]);
                break;

            case CT_Robinson:
                oSRS.SetRobinson(adfParam[1], adfParam[5], adfParam[6]);
                break;

            case CT_Sinusoidal:
                oSRS.SetSinusoidal(adfParam[1], adfParam[5], adfParam[6]);
                break;

            case CT_VanDerGrinten:
                oSRS.SetVDG(adfParam[1], adfParam[5], adfParam[6]);
                break;

            case CT_PolarStereographic:
                oSRS.SetPS(adfParam[0], adfParam[1], adfParam[4], adfParam[5],
                           adfParam[6]);
                break;

            case CT_LambertConfConic_2SP:
                oSRS.SetLCC(adfParam[2], adfParam[3], adfParam[0], adfParam[1],
                            adfParam[5], adfParam[6]);
                break;

            case CT_LambertConfConic_1SP:
                oSRS.SetLCC1SP(adfParam[0], adfParam[1], adfParam[4],
                               adfParam[5], adfParam[6]);
                break;

            case CT_AlbersEqualArea:
                oSRS.SetACEA(adfParam[0], adfParam[1], adfParam[2], adfParam[3],
                             adfParam[5], adfParam[6]);
                break;

            case CT_NewZealandMapGrid:
                oSRS.SetNZMG(adfParam[0], adfParam[1], adfParam[5],
                             adfParam[6]);
                break;

            case CT_CylindricalEqualArea:
                oSRS.SetCEA(adfParam[0], adfParam[1], adfParam[5], adfParam[6]);
                break;
            default:
                if (oSRS.IsProjected())
                {
                    const char *pszName = oSRS.GetName();
                    std::string osName(pszName ? pszName : "unnamed");
                    oSRS.Clear();
                    oSRS.SetLocalCS(osName.c_str());
                }
                break;
        }
    }

    if (psDefn->Model == ModelTypeProjected && psDefn->PCS != KvUserDefined &&
        !bGotFromEPSG)
    {
        OGRSpatialReference oSRSTest(oSRS);
        OGRSpatialReference oSRSTmp;

        const bool bPCSCodeValid =
            oSRSTmp.importFromEPSG(psDefn->PCS) == OGRERR_NONE;
        oSRSTmp.SetAxisMappingStrategy(OAMS_TRADITIONAL_GIS_ORDER);

        // Force axis to avoid issues with SRS with northing, easting order
        oSRSTest.SetAxes(nullptr, "X", OAO_East, "Y", OAO_North);
        oSRSTmp.SetAxes(nullptr, "X", OAO_East, "Y", OAO_North);

        const std::string osGTiffSRSSource =
            CPLGetConfigOption("GTIFF_SRS_SOURCE", "");
        const char *const apszOptions[] = {
            "IGNORE_DATA_AXIS_TO_SRS_AXIS_MAPPING=YES", nullptr};
        if (!bHasWarnedInconsistentGeogCRSEPSG &&
            !oSRSTmp.IsSame(&oSRS, apszOptions) &&
            EQUAL(osGTiffSRSSource.c_str(), ""))
        {
            // See https://github.com/OSGeo/gdal/issues/5399
            // where a file has inconsistent GeogSemiMinorAxisGeoKey /
            // GeogInvFlatteningGeoKey values, which cause its datum to be
            // considered as non-equivalent to the EPSG one.
            CPLError(
                CE_Warning, CPLE_AppDefined,
                "The definition of projected CRS EPSG:%d got from GeoTIFF keys "
                "is not the same as the one from the EPSG registry, "
                "which may cause issues during reprojection operations. "
                "Set GTIFF_SRS_SOURCE configuration option to EPSG to "
                "use official parameters (overriding the ones from GeoTIFF "
                "keys), "
                "or to GEOKEYS to use custom values from GeoTIFF keys "
                "and drop the EPSG code.",
                psDefn->PCS);
        }
        if (EQUAL(osGTiffSRSSource.c_str(), "EPSG"))
        {
            oSRS = oSRSTmp;
        }
        else if (bPCSCodeValid && EQUAL(osGTiffSRSSource.c_str(), ""))
        {
            oSRS.SetAuthority(nullptr, "EPSG", psDefn->PCS);
        }
    }

    if (oSRS.IsProjected() && oSRS.GetAxesCount() == 2)
    {
        const char *pszProjCRSName = oSRS.GetAttrValue("PROJCS");
        if (pszProjCRSName)
        {
            // Hack to be able to read properly what we have written for
            // ESRI:102113 (ESRI ancient WebMercator).
            if (EQUAL(pszProjCRSName, "WGS_1984_Web_Mercator"))
                oSRS.SetFromUserInput("ESRI:102113");
            // And for EPSG:900913
            else if (EQUAL(pszProjCRSName, "Google Maps Global Mercator"))
                oSRS.importFromEPSG(900913);
            else if (strchr(pszProjCRSName, '_'))
            {
                // Morph from potential ESRI name
                char *pszOfficialName = GTIFGetEPSGOfficialName(
                    hGTIF, PJ_TYPE_PROJECTED_CRS, pszProjCRSName);
                if (pszOfficialName)
                {
                    oSRS.SetProjCS(pszOfficialName);
                    CPLFree(pszOfficialName);
                }
            }
        }
    }

    /* ==================================================================== */
    /*      Handle vertical coordinate system information if we have it.    */
    /* ==================================================================== */
    bool bNeedManualVertCS = false;
    char citation[2048] = {'\0'};

    // See https://github.com/OSGeo/gdal/pull/4197
    if (verticalCSType > KvUserDefined || verticalDatum > KvUserDefined ||
        verticalUnits > KvUserDefined)
    {
        CPLError(CE_Warning, CPLE_AppDefined,
                 "At least one of VerticalCSTypeGeoKey, VerticalDatumGeoKey or "
                 "VerticalUnitsGeoKey has a value in the private user range. "
                 "Ignoring vertical information.");
        verticalCSType = 0;
        verticalDatum = 0;
        verticalUnits = 0;
    }

    if ((verticalCSType != 0 || verticalDatum != 0 || verticalUnits != 0) &&
        (oSRS.IsGeographic() || oSRS.IsProjected() || oSRS.IsLocal()))
    {
        if (GDALGTIFKeyGetASCII(hGTIF, VerticalCitationGeoKey, citation,
                                sizeof(citation)))
        {
            if (STARTS_WITH_CI(citation, "VCS Name = "))
            {
                memmove(citation, citation + strlen("VCS Name = "),
                        strlen(citation + strlen("VCS Name = ")) + 1);
                char *pszPipeChar = strchr(citation, '|');
                if (pszPipeChar)
                    *pszPipeChar = '\0';
            }
        }
        else
        {
            strcpy(citation, "unknown");
        }

        OGRSpatialReference oVertSRS;
        bool bCanBuildCompoundCRS = oSRS.GetRoot() != nullptr;
        if (verticalCSType != KvUserDefined && verticalCSType > 0)
        {
            if (!(oVertSRS.importFromEPSG(verticalCSType) == OGRERR_NONE &&
                  oVertSRS.IsVertical()))
            {
                bCanBuildCompoundCRS = false;
            }
        }

        if (bCanBuildCompoundCRS)
        {
            const char *pszHorizontalName = oSRS.GetName();
            const std::string osHorizontalName(
                pszHorizontalName ? pszHorizontalName : "unnamed");
            /* --------------------------------------------------------------------
             */
            /*      Promote to being a compound coordinate system. */
            /* --------------------------------------------------------------------
             */
            OGR_SRSNode *poOldRoot = oSRS.GetRoot()->Clone();

            oSRS.Clear();

            /* --------------------------------------------------------------------
             */
            /*      Set COMPD_CS name. */
            /* --------------------------------------------------------------------
             */
            char szCTString[512];
            szCTString[0] = '\0';
            if (GDALGTIFKeyGetASCII(hGTIF, GTCitationGeoKey, szCTString,
                                    sizeof(szCTString)) &&
                strstr(szCTString, " = ") == nullptr)
            {
                oSRS.SetNode("COMPD_CS", szCTString);
            }
            else
            {
                oSRS.SetNode("COMPD_CS",
                             (osHorizontalName + " + " + citation).c_str());
            }

            oSRS.GetRoot()->AddChild(poOldRoot);

            /* --------------------------------------------------------------------
             */
            /*      If we have the vertical cs, try to look it up, and use the
             */
            /*      definition provided by that. */
            /* --------------------------------------------------------------------
             */
            bNeedManualVertCS = true;

            if (!oVertSRS.IsEmpty())
            {
                oSRS.GetRoot()->AddChild(oVertSRS.GetRoot()->Clone());
                bNeedManualVertCS = false;
            }
        }
    }

    /* -------------------------------------------------------------------- */
    /*      Collect some information from the VerticalCS if not provided    */
    /*      via geokeys.                                                    */
    /* -------------------------------------------------------------------- */
    if (bNeedManualVertCS)
    {
        FillCompoundCRSWithManualVertCS(hGTIF, oSRS, citation, verticalDatum,
                                        verticalUnits);
    }

    // Hack for tiff_read.py:test_tiff_grads so as to normalize angular
    // parameters to grad
    if (psDefn->UOMAngleInDegrees != 1.0)
    {
        char *pszWKT = nullptr;
        const char *const apszOptions[] = {
            "FORMAT=WKT1", "ADD_TOWGS84_ON_EXPORT_TO_WKT1=NO", nullptr};
        if (oSRS.exportToWkt(&pszWKT, apszOptions) == OGRERR_NONE)
        {
            const char *const apszOptionsImport[] = {
#if PROJ_AT_LEAST_VERSION(9, 1, 0)
                "UNSET_IDENTIFIERS_IF_INCOMPATIBLE_DEF=NO",
#endif
                nullptr
            };
            oSRS.importFromWkt(pszWKT, apszOptionsImport);
        }
        CPLFree(pszWKT);
    }

    oSRS.StripTOWGS84IfKnownDatumAndAllowed();

    double dfCoordinateEpoch = 0.0;
    if (GDALGTIFKeyGetDOUBLE(hGTIF, CoordinateEpochGeoKey, &dfCoordinateEpoch,
                             0, 1))
    {
        oSRS.SetCoordinateEpoch(dfCoordinateEpoch);
    }

    return OGRSpatialReference::ToHandle(oSRS.Clone());
}

/************************************************************************/
/*                          GTIFGetOGISDefn()                           */
/************************************************************************/

char *GTIFGetOGISDefn(GTIF *hGTIF, GTIFDefn *psDefn)
{
    OGRSpatialReferenceH hSRS = GTIFGetOGISDefnAsOSR(hGTIF, psDefn);

    char *pszWKT = nullptr;
    if (hSRS && OGRSpatialReference::FromHandle(hSRS)->exportToWkt(&pszWKT) ==
                    OGRERR_NONE)
    {
        OSRDestroySpatialReference(hSRS);
        return pszWKT;
    }
    CPLFree(pszWKT);
    OSRDestroySpatialReference(hSRS);

    return nullptr;
}

/************************************************************************/
/*                     OGCDatumName2EPSGDatumCode()                     */
/************************************************************************/

static int OGCDatumName2EPSGDatumCode(GTIF *psGTIF, const char *pszOGCName)

{
    int nReturn = KvUserDefined;

    /* -------------------------------------------------------------------- */
    /*      Do we know it as a built in?                                    */
    /* -------------------------------------------------------------------- */
    if (EQUAL(pszOGCName, "NAD27") ||
        EQUAL(pszOGCName, "North_American_Datum_1927"))
        return Datum_North_American_Datum_1927;
    else if (EQUAL(pszOGCName, "NAD83") ||
             EQUAL(pszOGCName, "North_American_Datum_1983"))
        return Datum_North_American_Datum_1983;
    else if (EQUAL(pszOGCName, "WGS84") || EQUAL(pszOGCName, "WGS_1984") ||
             EQUAL(pszOGCName, "WGS 84"))
        return Datum_WGS84;
    else if (EQUAL(pszOGCName, "WGS72") || EQUAL(pszOGCName, "WGS_1972"))
        return Datum_WGS72;

    /* Search in database */
    auto ctx =
        static_cast<PJ_CONTEXT *>(GTIFGetPROJContext(psGTIF, true, nullptr));
    const PJ_TYPE searchType = PJ_TYPE_GEODETIC_REFERENCE_FRAME;
    auto list = proj_create_from_name(ctx, "EPSG", pszOGCName, &searchType, 1,
                                      true, /* approximate match */
                                      10, nullptr);
    if (list)
    {
        const auto listSize = proj_list_get_count(list);
        for (int i = 0; nReturn == KvUserDefined && i < listSize; i++)
        {
            auto datum = proj_list_get(ctx, list, i);
            if (datum)
            {
                const char *pszDatumName = proj_get_name(datum);
                if (pszDatumName)
                {
                    char *pszTmp = CPLStrdup(pszDatumName);
                    WKTMassageDatum(&pszTmp);
                    if (EQUAL(pszTmp, pszOGCName))
                    {
                        const char *pszCode = proj_get_id_code(datum, 0);
                        if (pszCode)
                        {
                            nReturn = atoi(pszCode);
                        }
                    }
                    CPLFree(pszTmp);
                }
            }
            proj_destroy(datum);
        }
        proj_list_destroy(list);
    }

    return nReturn;
}

/************************************************************************/
/*                        GTIFSetFromOGISDefn()                         */
/*                                                                      */
/*      Write GeoTIFF projection tags from an OGC WKT definition.       */
/************************************************************************/

int GTIFSetFromOGISDefn(GTIF *psGTIF, const char *pszOGCWKT)

{
    /* -------------------------------------------------------------------- */
    /*      Create an OGRSpatialReference object corresponding to the       */
    /*      string.                                                         */
    /* -------------------------------------------------------------------- */

    OGRSpatialReference oSRS;
    if (oSRS.importFromWkt(pszOGCWKT) != OGRERR_NONE)
    {
        return FALSE;
    }
    return GTIFSetFromOGISDefnEx(psGTIF, OGRSpatialReference::ToHandle(&oSRS),
                                 GEOTIFF_KEYS_STANDARD, GEOTIFF_VERSION_1_0);
}

int GTIFSetFromOGISDefnEx(GTIF *psGTIF, OGRSpatialReferenceH hSRS,
                          GTIFFKeysFlavorEnum eFlavor,
                          GeoTIFFVersionEnum eVersion)
{
    std::map<geokey_t, std::string> oMapAsciiKeys;

    GTIFKeySet(psGTIF, GTRasterTypeGeoKey, TYPE_SHORT, 1, RasterPixelIsArea);

    const OGRSpatialReference *poSRS = OGRSpatialReference::FromHandle(hSRS);

    /* -------------------------------------------------------------------- */
    /*      Set version number.                                             */
    /* -------------------------------------------------------------------- */
    if (eVersion == GEOTIFF_VERSION_AUTO)
    {
        if (poSRS->IsCompound() ||
            (poSRS->IsGeographic() && poSRS->GetAxesCount() == 3))
        {
            eVersion = GEOTIFF_VERSION_1_1;
        }
        else
        {
            eVersion = GEOTIFF_VERSION_1_0;
        }
    }
    CPLAssert(eVersion == GEOTIFF_VERSION_1_0 ||
              eVersion == GEOTIFF_VERSION_1_1);
    if (eVersion >= GEOTIFF_VERSION_1_1)
    {
#if LIBGEOTIFF_VERSION >= 1600
        GTIFSetVersionNumbers(psGTIF, GEOTIFF_SPEC_1_1_VERSION,
                              GEOTIFF_SPEC_1_1_KEY_REVISION,
                              GEOTIFF_SPEC_1_1_MINOR_REVISION);
#else
        CPLError(CE_Warning, CPLE_AppDefined,
                 "Setting GeoTIFF 1.1 requires libgeotiff >= 1.6. Key values "
                 "will be written as GeoTIFF 1.1, but the version number "
                 "will be seen as 1.0, which might confuse GeoTIFF readers");
#endif
    }

    /* -------------------------------------------------------------------- */
    /*      Get the ellipsoid definition.                                   */
    /* -------------------------------------------------------------------- */
    short nSpheroid = KvUserDefined;

    if (poSRS->GetAuthorityName("PROJCS|GEOGCS|DATUM|SPHEROID") != nullptr &&
        EQUAL(poSRS->GetAuthorityName("PROJCS|GEOGCS|DATUM|SPHEROID"), "EPSG"))
    {
        nSpheroid = static_cast<short>(
            atoi(poSRS->GetAuthorityCode("PROJCS|GEOGCS|DATUM|SPHEROID")));
    }
    else if (poSRS->GetAuthorityName("GEOGCS|DATUM|SPHEROID") != nullptr &&
             EQUAL(poSRS->GetAuthorityName("GEOGCS|DATUM|SPHEROID"), "EPSG"))
    {
        nSpheroid = static_cast<short>(
            atoi(poSRS->GetAuthorityCode("GEOGCS|DATUM|SPHEROID")));
    }

    OGRErr eErr = OGRERR_NONE;
    double dfSemiMajor = 0;
    double dfInvFlattening = 0;
    bool bHasEllipsoid = false;
    if (!poSRS->IsLocal())
    {
        bHasEllipsoid = true;
        if (poSRS->IsCompound())
        {
            OGRSpatialReference oSRSTmp(*poSRS);
            oSRSTmp.StripVertical();
            bHasEllipsoid = CPL_TO_BOOL(!oSRSTmp.IsLocal());
        }
        if (bHasEllipsoid)
        {
            dfSemiMajor = poSRS->GetSemiMajor(&eErr);
            dfInvFlattening = poSRS->GetInvFlattening(&eErr);
            if (eErr != OGRERR_NONE)
            {
                dfSemiMajor = 0.0;
                dfInvFlattening = 0.0;
            }
        }
    }

    /* -------------------------------------------------------------------- */
    /*      Get the Datum so we can special case a few PCS codes.           */
    /* -------------------------------------------------------------------- */
    int nDatum = KvUserDefined;

    if (poSRS->GetAuthorityName("PROJCS|GEOGCS|DATUM") != nullptr &&
        EQUAL(poSRS->GetAuthorityName("PROJCS|GEOGCS|DATUM"), "EPSG"))
        nDatum = atoi(poSRS->GetAuthorityCode("PROJCS|GEOGCS|DATUM"));
    else if (poSRS->GetAuthorityName("GEOGCS|DATUM") != nullptr &&
             EQUAL(poSRS->GetAuthorityName("GEOGCS|DATUM"), "EPSG"))
        nDatum = atoi(poSRS->GetAuthorityCode("GEOGCS|DATUM"));
    else if (poSRS->GetAttrValue("DATUM") != nullptr)
        nDatum =
            OGCDatumName2EPSGDatumCode(psGTIF, poSRS->GetAttrValue("DATUM"));

    /* -------------------------------------------------------------------- */
    /*      Get the GCS if possible.                                        */
    /* -------------------------------------------------------------------- */
    int nGCS = KvUserDefined;

    if (poSRS->GetAuthorityName("PROJCS|GEOGCS") != nullptr &&
        EQUAL(poSRS->GetAuthorityName("PROJCS|GEOGCS"), "EPSG"))
        nGCS = atoi(poSRS->GetAuthorityCode("PROJCS|GEOGCS"));
    else if (poSRS->GetAuthorityName("GEOGCS") != nullptr &&
             EQUAL(poSRS->GetAuthorityName("GEOGCS"), "EPSG"))
        nGCS = atoi(poSRS->GetAuthorityCode("GEOGCS"));

    int nVerticalCSKeyValue = 0;
    bool hasEllipsoidHeight = !poSRS->IsCompound() && poSRS->IsGeographic() &&
                              poSRS->GetAxesCount() == 3;
    if (nGCS == 4937 && eVersion >= GEOTIFF_VERSION_1_1)
    {
        // Workaround a bug of PROJ 6.3.0
        // See https://github.com/OSGeo/PROJ/pull/1880
        // EPSG:4937 = ETRS89 3D
        hasEllipsoidHeight = true;
        nVerticalCSKeyValue = nGCS;
        nGCS = 4258;  // ETRS89 2D
    }
    else if (nGCS != KvUserDefined)
    {
        OGRSpatialReference oGeogCRS;
        if (oGeogCRS.importFromEPSG(nGCS) == OGRERR_NONE &&
            oGeogCRS.IsGeographic() && oGeogCRS.GetAxesCount() == 3)
        {
            hasEllipsoidHeight = true;
            if (eVersion >= GEOTIFF_VERSION_1_1)
            {
                const auto candidate_nVerticalCSKeyValue = nGCS;
                nGCS = KvUserDefined;

                // In case of a geographic 3D CRS, find the corresponding
                // geographic 2D CRS
                auto ctx = static_cast<PJ_CONTEXT *>(
                    GTIFGetPROJContext(psGTIF, true, nullptr));
                const auto type = PJ_TYPE_GEOGRAPHIC_2D_CRS;
                auto list = proj_create_from_name(ctx, "EPSG",
                                                  oGeogCRS.GetName(), &type, 1,
                                                  false,  // exact match
                                                  1,  // result set limit size,
                                                  nullptr);
                if (list && proj_list_get_count(list) == 1)
                {
                    auto crs2D = proj_list_get(ctx, list, 0);
                    if (crs2D)
                    {
                        const char *pszCode = proj_get_id_code(crs2D, 0);
                        if (pszCode)
                        {
                            nVerticalCSKeyValue = candidate_nVerticalCSKeyValue;
                            nGCS = atoi(pszCode);
                        }
                        proj_destroy(crs2D);
                    }
                }
                proj_list_destroy(list);
            }
        }
    }

    // Deprecated way of encoding ellipsoidal height
    if (hasEllipsoidHeight && nVerticalCSKeyValue == 0)
    {
        if (nGCS == 4979 || nDatum == 6326 || nSpheroid == 7030)
        {
            nVerticalCSKeyValue = 5030;  // WGS_84_ellipsoid
            if (nGCS == 4979 || nDatum == 6326)
            {
                nGCS = 4326;
            }
        }
        else if (nDatum >= 6001 && nDatum <= 6033)
        {
            nVerticalCSKeyValue = nDatum - 1000;
        }
        else if (nSpheroid >= 7001 && nSpheroid <= 7033)
        {
            nVerticalCSKeyValue = nSpheroid - 2000;
        }
    }

    if (nGCS > 32767)
        nGCS = KvUserDefined;

    /* -------------------------------------------------------------------- */
    /*      Get the linear units.                                           */
    /* -------------------------------------------------------------------- */
    const char *pszLinearUOMNameTmp = nullptr;
    const double dfLinearUOM = poSRS->GetLinearUnits(&pszLinearUOMNameTmp);
    const std::string osLinearUOMName(pszLinearUOMNameTmp ? pszLinearUOMNameTmp
                                                          : "");
    int nUOMLengthCode = 9001;  // Meters.

    if (poSRS->GetAuthorityName("PROJCS|UNIT") != nullptr &&
        EQUAL(poSRS->GetAuthorityName("PROJCS|UNIT"), "EPSG") &&
        poSRS->GetAttrNode("PROJCS|UNIT") != poSRS->GetAttrNode("GEOGCS|UNIT"))
        nUOMLengthCode = atoi(poSRS->GetAuthorityCode("PROJCS|UNIT"));
    else if (EQUAL(osLinearUOMName.c_str(), SRS_UL_FOOT) ||
             fabs(dfLinearUOM - GTIFAtof(SRS_UL_FOOT_CONV)) < 0.0000001)
        nUOMLengthCode = 9002;  // International foot.
    else if (EQUAL(osLinearUOMName.c_str(), SRS_UL_US_FOOT) ||
             std::abs(dfLinearUOM - GTIFAtof(SRS_UL_US_FOOT_CONV)) < 0.0000001)
        nUOMLengthCode = 9003;  // US survey foot.
    else if (fabs(dfLinearUOM - 1.0) > 0.00000001)
        nUOMLengthCode = KvUserDefined;

    /* -------------------------------------------------------------------- */
    /*      Get some authority values.                                      */
    /* -------------------------------------------------------------------- */
    int nPCS = KvUserDefined;

    if (poSRS->GetAuthorityName("PROJCS") != nullptr &&
        EQUAL(poSRS->GetAuthorityName("PROJCS"), "EPSG"))
    {
        nPCS = atoi(poSRS->GetAuthorityCode("PROJCS"));
        if (nPCS > 32767)
            nPCS = KvUserDefined;
    }

    /* -------------------------------------------------------------------- */
    /*      Handle the projection transformation.                           */
    /* -------------------------------------------------------------------- */
    bool bWritePEString = false;
    bool bUnknownProjection = false;

    const OGRSpatialReference *poSRSCompatibleOfWKT1 = poSRS;
#if PROJ_AT_LEAST_VERSION(6, 3, 0)
    OGRSpatialReference oSRSCompatibleOfWKT1;
    if (poSRS->IsProjected() && !poSRS->IsCompound() &&
        poSRS->GetAxesCount() == 3)
    {
        oSRSCompatibleOfWKT1 = *poSRS;
        oSRSCompatibleOfWKT1.DemoteTo2D(nullptr);
        poSRSCompatibleOfWKT1 = &oSRSCompatibleOfWKT1;
        bWritePEString = true;
    }
#endif

    const char *pszProjection =
        poSRSCompatibleOfWKT1->GetAttrValue("PROJECTION");
    if (nPCS != KvUserDefined)
    {
        // If ESRI_PE flavor is explicitly required, then for EPSG:3857
        // we will have to write a completely non-standard definition
        // that requires not setting GTModelTypeGeoKey to ProjectedCSTypeGeoKey.
        if (eFlavor == GEOTIFF_KEYS_ESRI_PE && nPCS == 3857)
        {
            bWritePEString = true;
        }
        else
        {
            GTIFKeySet(psGTIF, GTModelTypeGeoKey, TYPE_SHORT, 1,
                       ModelTypeProjected);
            GTIFKeySet(psGTIF, ProjectedCSTypeGeoKey, TYPE_SHORT, 1, nPCS);
        }
    }
    else if (poSRSCompatibleOfWKT1->IsGeocentric())
    {
        GTIFKeySet(psGTIF, GTModelTypeGeoKey, TYPE_SHORT, 1,
                   ModelTypeGeocentric);
    }
    else if (pszProjection == nullptr)
    {
        if (poSRSCompatibleOfWKT1->IsGeographic())
            GTIFKeySet(psGTIF, GTModelTypeGeoKey, TYPE_SHORT, 1,
                       ModelTypeGeographic);
        // Otherwise, presumably something like LOCAL_CS.
    }
    else if (EQUAL(pszProjection, SRS_PT_ALBERS_CONIC_EQUAL_AREA))
    {
        GTIFKeySet(psGTIF, GTModelTypeGeoKey, TYPE_SHORT, 1,
                   ModelTypeProjected);
        GTIFKeySet(psGTIF, ProjectedCSTypeGeoKey, TYPE_SHORT, 1, KvUserDefined);
        GTIFKeySet(psGTIF, ProjectionGeoKey, TYPE_SHORT, 1, KvUserDefined);

        GTIFKeySet(psGTIF, ProjCoordTransGeoKey, TYPE_SHORT, 1,
                   CT_AlbersEqualArea);

        GTIFKeySet(psGTIF, ProjStdParallelGeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_STANDARD_PARALLEL_1, 0.0));

        GTIFKeySet(psGTIF, ProjStdParallel2GeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_STANDARD_PARALLEL_2, 0.0));

        GTIFKeySet(psGTIF, ProjNatOriginLatGeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_LATITUDE_OF_CENTER, 0.0));

        GTIFKeySet(psGTIF, ProjNatOriginLongGeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_LONGITUDE_OF_CENTER, 0.0));

        GTIFKeySet(
            psGTIF, ProjFalseEastingGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetProjParm(SRS_PP_FALSE_EASTING, 0.0));

        GTIFKeySet(
            psGTIF, ProjFalseNorthingGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetProjParm(SRS_PP_FALSE_NORTHING, 0.0));
    }

    else if (poSRSCompatibleOfWKT1->GetUTMZone() != 0)
    {
        GTIFKeySet(psGTIF, GTModelTypeGeoKey, TYPE_SHORT, 1,
                   ModelTypeProjected);

        int bNorth = 0;
        const int nZone = poSRSCompatibleOfWKT1->GetUTMZone(&bNorth);

        if (nDatum == Datum_North_American_Datum_1983 && nZone >= 3 &&
            nZone <= 22 && bNorth && nUOMLengthCode == 9001)
        {
            nPCS = 26900 + nZone;

            GTIFKeySet(psGTIF, ProjectedCSTypeGeoKey, TYPE_SHORT, 1, nPCS);
        }
        else if (nDatum == Datum_North_American_Datum_1927 && nZone >= 3 &&
                 nZone <= 22 && bNorth && nUOMLengthCode == 9001)
        {
            nPCS = 26700 + nZone;

            GTIFKeySet(psGTIF, ProjectedCSTypeGeoKey, TYPE_SHORT, 1, nPCS);
        }
        else if (nDatum == Datum_WGS84 && nUOMLengthCode == 9001)
        {
            if (bNorth)
                nPCS = 32600 + nZone;
            else
                nPCS = 32700 + nZone;

            GTIFKeySet(psGTIF, ProjectedCSTypeGeoKey, TYPE_SHORT, 1, nPCS);
        }
        else
        {
            const int nProjection = nZone + (bNorth ? 16000 : 16100);
            GTIFKeySet(psGTIF, ProjectedCSTypeGeoKey, TYPE_SHORT, 1,
                       KvUserDefined);

            GTIFKeySet(psGTIF, ProjectionGeoKey, TYPE_SHORT, 1, nProjection);
        }
    }

    else if (EQUAL(pszProjection, SRS_PT_TRANSVERSE_MERCATOR))
    {
        GTIFKeySet(psGTIF, GTModelTypeGeoKey, TYPE_SHORT, 1,
                   ModelTypeProjected);
        GTIFKeySet(psGTIF, ProjectedCSTypeGeoKey, TYPE_SHORT, 1, KvUserDefined);
        GTIFKeySet(psGTIF, ProjectionGeoKey, TYPE_SHORT, 1, KvUserDefined);

        GTIFKeySet(psGTIF, ProjCoordTransGeoKey, TYPE_SHORT, 1,
                   CT_TransverseMercator);

        GTIFKeySet(psGTIF, ProjNatOriginLatGeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_LATITUDE_OF_ORIGIN, 0.0));

        GTIFKeySet(psGTIF, ProjNatOriginLongGeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_CENTRAL_MERIDIAN, 0.0));

        GTIFKeySet(
            psGTIF, ProjScaleAtNatOriginGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetNormProjParm(SRS_PP_SCALE_FACTOR, 1.0));

        GTIFKeySet(
            psGTIF, ProjFalseEastingGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetProjParm(SRS_PP_FALSE_EASTING, 0.0));

        GTIFKeySet(
            psGTIF, ProjFalseNorthingGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetProjParm(SRS_PP_FALSE_NORTHING, 0.0));
    }

    else if (EQUAL(pszProjection, SRS_PT_TRANSVERSE_MERCATOR_SOUTH_ORIENTED))
    {
        GTIFKeySet(psGTIF, GTModelTypeGeoKey, TYPE_SHORT, 1,
                   ModelTypeProjected);
        GTIFKeySet(psGTIF, ProjectedCSTypeGeoKey, TYPE_SHORT, 1, KvUserDefined);
        GTIFKeySet(psGTIF, ProjectionGeoKey, TYPE_SHORT, 1, KvUserDefined);

        GTIFKeySet(psGTIF, ProjCoordTransGeoKey, TYPE_SHORT, 1,
                   CT_TransvMercator_SouthOriented);

        GTIFKeySet(psGTIF, ProjNatOriginLatGeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_LATITUDE_OF_ORIGIN, 0.0));

        GTIFKeySet(psGTIF, ProjNatOriginLongGeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_CENTRAL_MERIDIAN, 0.0));

        GTIFKeySet(
            psGTIF, ProjScaleAtNatOriginGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetNormProjParm(SRS_PP_SCALE_FACTOR, 1.0));

        GTIFKeySet(
            psGTIF, ProjFalseEastingGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetProjParm(SRS_PP_FALSE_EASTING, 0.0));

        GTIFKeySet(
            psGTIF, ProjFalseNorthingGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetProjParm(SRS_PP_FALSE_NORTHING, 0.0));
    }

    else if (EQUAL(pszProjection, SRS_PT_MERCATOR_2SP) ||
             EQUAL(pszProjection, SRS_PT_MERCATOR_1SP))

    {
        GTIFKeySet(psGTIF, GTModelTypeGeoKey, TYPE_SHORT, 1,
                   ModelTypeProjected);
        GTIFKeySet(psGTIF, ProjectedCSTypeGeoKey, TYPE_SHORT, 1, KvUserDefined);
        GTIFKeySet(psGTIF, ProjectionGeoKey, TYPE_SHORT, 1, KvUserDefined);

        GTIFKeySet(psGTIF, ProjCoordTransGeoKey, TYPE_SHORT, 1, CT_Mercator);

        GTIFKeySet(psGTIF, ProjNatOriginLatGeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_LATITUDE_OF_ORIGIN, 0.0));

        GTIFKeySet(psGTIF, ProjNatOriginLongGeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_CENTRAL_MERIDIAN, 0.0));

        if (EQUAL(pszProjection, SRS_PT_MERCATOR_2SP))
            GTIFKeySet(psGTIF, ProjStdParallel1GeoKey, TYPE_DOUBLE, 1,
                       poSRSCompatibleOfWKT1->GetNormProjParm(
                           SRS_PP_STANDARD_PARALLEL_1, 0.0));
        else
            GTIFKeySet(psGTIF, ProjScaleAtNatOriginGeoKey, TYPE_DOUBLE, 1,
                       poSRSCompatibleOfWKT1->GetNormProjParm(
                           SRS_PP_SCALE_FACTOR, 1.0));

        GTIFKeySet(
            psGTIF, ProjFalseEastingGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetProjParm(SRS_PP_FALSE_EASTING, 0.0));

        GTIFKeySet(
            psGTIF, ProjFalseNorthingGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetProjParm(SRS_PP_FALSE_NORTHING, 0.0));
    }

    else if (EQUAL(pszProjection, SRS_PT_OBLIQUE_STEREOGRAPHIC))
    {
        GTIFKeySet(psGTIF, GTModelTypeGeoKey, TYPE_SHORT, 1,
                   ModelTypeProjected);
        GTIFKeySet(psGTIF, ProjectedCSTypeGeoKey, TYPE_SHORT, 1, KvUserDefined);
        GTIFKeySet(psGTIF, ProjectionGeoKey, TYPE_SHORT, 1, KvUserDefined);

        GTIFKeySet(psGTIF, ProjCoordTransGeoKey, TYPE_SHORT, 1,
                   CT_ObliqueStereographic);

        GTIFKeySet(psGTIF, ProjNatOriginLatGeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_LATITUDE_OF_ORIGIN, 0.0));

        GTIFKeySet(psGTIF, ProjNatOriginLongGeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_CENTRAL_MERIDIAN, 0.0));

        GTIFKeySet(
            psGTIF, ProjScaleAtNatOriginGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetNormProjParm(SRS_PP_SCALE_FACTOR, 1.0));

        GTIFKeySet(
            psGTIF, ProjFalseEastingGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetProjParm(SRS_PP_FALSE_EASTING, 0.0));

        GTIFKeySet(
            psGTIF, ProjFalseNorthingGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetProjParm(SRS_PP_FALSE_NORTHING, 0.0));
    }

    else if (EQUAL(pszProjection, SRS_PT_STEREOGRAPHIC))
    {
        GTIFKeySet(psGTIF, GTModelTypeGeoKey, TYPE_SHORT, 1,
                   ModelTypeProjected);
        GTIFKeySet(psGTIF, ProjectedCSTypeGeoKey, TYPE_SHORT, 1, KvUserDefined);
        GTIFKeySet(psGTIF, ProjectionGeoKey, TYPE_SHORT, 1, KvUserDefined);

        GTIFKeySet(psGTIF, ProjCoordTransGeoKey, TYPE_SHORT, 1,
                   CT_Stereographic);

        GTIFKeySet(psGTIF, ProjCenterLatGeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_LATITUDE_OF_ORIGIN, 0.0));

        GTIFKeySet(psGTIF, ProjCenterLongGeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_CENTRAL_MERIDIAN, 0.0));

        GTIFKeySet(
            psGTIF, ProjScaleAtNatOriginGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetNormProjParm(SRS_PP_SCALE_FACTOR, 1.0));

        GTIFKeySet(
            psGTIF, ProjFalseEastingGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetProjParm(SRS_PP_FALSE_EASTING, 0.0));

        GTIFKeySet(
            psGTIF, ProjFalseNorthingGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetProjParm(SRS_PP_FALSE_NORTHING, 0.0));
    }

    else if (EQUAL(pszProjection, SRS_PT_POLAR_STEREOGRAPHIC))
    {
        GTIFKeySet(psGTIF, GTModelTypeGeoKey, TYPE_SHORT, 1,
                   ModelTypeProjected);
        GTIFKeySet(psGTIF, ProjectedCSTypeGeoKey, TYPE_SHORT, 1, KvUserDefined);
        GTIFKeySet(psGTIF, ProjectionGeoKey, TYPE_SHORT, 1, KvUserDefined);

        GTIFKeySet(psGTIF, ProjCoordTransGeoKey, TYPE_SHORT, 1,
                   CT_PolarStereographic);

        GTIFKeySet(psGTIF, ProjNatOriginLatGeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_LATITUDE_OF_ORIGIN, 0.0));

        GTIFKeySet(psGTIF, ProjStraightVertPoleLongGeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_CENTRAL_MERIDIAN, 0.0));

        GTIFKeySet(
            psGTIF, ProjScaleAtNatOriginGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetNormProjParm(SRS_PP_SCALE_FACTOR, 1.0));

        GTIFKeySet(
            psGTIF, ProjFalseEastingGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetProjParm(SRS_PP_FALSE_EASTING, 0.0));

        GTIFKeySet(
            psGTIF, ProjFalseNorthingGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetProjParm(SRS_PP_FALSE_NORTHING, 0.0));
    }

    else if (EQUAL(pszProjection, SRS_PT_HOTINE_OBLIQUE_MERCATOR))
    {
        GTIFKeySet(psGTIF, GTModelTypeGeoKey, TYPE_SHORT, 1,
                   ModelTypeProjected);
        GTIFKeySet(psGTIF, ProjectedCSTypeGeoKey, TYPE_SHORT, 1, KvUserDefined);
        GTIFKeySet(psGTIF, ProjectionGeoKey, TYPE_SHORT, 1, KvUserDefined);

        GTIFKeySet(psGTIF, ProjCoordTransGeoKey, TYPE_SHORT, 1,
                   CT_ObliqueMercator);

        GTIFKeySet(psGTIF, ProjCenterLatGeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_LATITUDE_OF_CENTER, 0.0));

        GTIFKeySet(psGTIF, ProjCenterLongGeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_LONGITUDE_OF_CENTER, 0.0));

        GTIFKeySet(psGTIF, ProjAzimuthAngleGeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(SRS_PP_AZIMUTH, 0.0));

        GTIFKeySet(psGTIF, ProjRectifiedGridAngleGeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_RECTIFIED_GRID_ANGLE, 0.0));

        GTIFKeySet(
            psGTIF, ProjScaleAtCenterGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetNormProjParm(SRS_PP_SCALE_FACTOR, 1.0));

        GTIFKeySet(
            psGTIF, ProjFalseEastingGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetProjParm(SRS_PP_FALSE_EASTING, 0.0));

        GTIFKeySet(
            psGTIF, ProjFalseNorthingGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetProjParm(SRS_PP_FALSE_NORTHING, 0.0));
    }

    else if (EQUAL(pszProjection,
                   SRS_PT_HOTINE_OBLIQUE_MERCATOR_AZIMUTH_CENTER))
    {
        GTIFKeySet(psGTIF, GTModelTypeGeoKey, TYPE_SHORT, 1,
                   ModelTypeProjected);
        GTIFKeySet(psGTIF, ProjectedCSTypeGeoKey, TYPE_SHORT, 1, KvUserDefined);
        GTIFKeySet(psGTIF, ProjectionGeoKey, TYPE_SHORT, 1, KvUserDefined);

        GTIFKeySet(psGTIF, ProjCoordTransGeoKey, TYPE_SHORT, 1,
                   CT_HotineObliqueMercatorAzimuthCenter);

        GTIFKeySet(psGTIF, ProjCenterLatGeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_LATITUDE_OF_CENTER, 0.0));

        GTIFKeySet(psGTIF, ProjCenterLongGeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_LONGITUDE_OF_CENTER, 0.0));

        GTIFKeySet(psGTIF, ProjAzimuthAngleGeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(SRS_PP_AZIMUTH, 0.0));

        GTIFKeySet(psGTIF, ProjRectifiedGridAngleGeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_RECTIFIED_GRID_ANGLE, 0.0));

        GTIFKeySet(
            psGTIF, ProjScaleAtCenterGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetNormProjParm(SRS_PP_SCALE_FACTOR, 1.0));

        GTIFKeySet(
            psGTIF, ProjFalseEastingGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetProjParm(SRS_PP_FALSE_EASTING, 0.0));

        GTIFKeySet(
            psGTIF, ProjFalseNorthingGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetProjParm(SRS_PP_FALSE_NORTHING, 0.0));
    }

    else if (EQUAL(pszProjection, "Laborde_Oblique_Mercator"))
    {
        GTIFKeySet(psGTIF, GTModelTypeGeoKey, TYPE_SHORT, 1,
                   ModelTypeProjected);
        GTIFKeySet(psGTIF, ProjectedCSTypeGeoKey, TYPE_SHORT, 1, KvUserDefined);
        GTIFKeySet(psGTIF, ProjectionGeoKey, TYPE_SHORT, 1, KvUserDefined);

        GTIFKeySet(psGTIF, ProjCoordTransGeoKey, TYPE_SHORT, 1,
                   CT_ObliqueMercator_Laborde);

        GTIFKeySet(psGTIF, ProjCenterLatGeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_LATITUDE_OF_CENTER, 0.0));

        GTIFKeySet(psGTIF, ProjCenterLongGeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_LONGITUDE_OF_CENTER, 0.0));

        GTIFKeySet(psGTIF, ProjAzimuthAngleGeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(SRS_PP_AZIMUTH, 0.0));

        GTIFKeySet(
            psGTIF, ProjScaleAtCenterGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetNormProjParm(SRS_PP_SCALE_FACTOR, 1.0));

        GTIFKeySet(
            psGTIF, ProjFalseEastingGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetProjParm(SRS_PP_FALSE_EASTING, 0.0));

        GTIFKeySet(
            psGTIF, ProjFalseNorthingGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetProjParm(SRS_PP_FALSE_NORTHING, 0.0));
    }

    else if (EQUAL(pszProjection, SRS_PT_CASSINI_SOLDNER))
    {
        GTIFKeySet(psGTIF, GTModelTypeGeoKey, TYPE_SHORT, 1,
                   ModelTypeProjected);
        GTIFKeySet(psGTIF, ProjectedCSTypeGeoKey, TYPE_SHORT, 1, KvUserDefined);
        GTIFKeySet(psGTIF, ProjectionGeoKey, TYPE_SHORT, 1, KvUserDefined);

        GTIFKeySet(psGTIF, ProjCoordTransGeoKey, TYPE_SHORT, 1,
                   CT_CassiniSoldner);

        GTIFKeySet(psGTIF, ProjNatOriginLatGeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_LATITUDE_OF_ORIGIN, 0.0));

        GTIFKeySet(psGTIF, ProjNatOriginLongGeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_CENTRAL_MERIDIAN, 0.0));

        GTIFKeySet(
            psGTIF, ProjFalseEastingGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetProjParm(SRS_PP_FALSE_EASTING, 0.0));

        GTIFKeySet(
            psGTIF, ProjFalseNorthingGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetProjParm(SRS_PP_FALSE_NORTHING, 0.0));
    }

    else if (EQUAL(pszProjection, SRS_PT_EQUIDISTANT_CONIC))
    {
        GTIFKeySet(psGTIF, GTModelTypeGeoKey, TYPE_SHORT, 1,
                   ModelTypeProjected);
        GTIFKeySet(psGTIF, ProjectedCSTypeGeoKey, TYPE_SHORT, 1, KvUserDefined);
        GTIFKeySet(psGTIF, ProjectionGeoKey, TYPE_SHORT, 1, KvUserDefined);

        GTIFKeySet(psGTIF, ProjCoordTransGeoKey, TYPE_SHORT, 1,
                   CT_EquidistantConic);

        GTIFKeySet(psGTIF, ProjStdParallel1GeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_STANDARD_PARALLEL_1, 0.0));

        GTIFKeySet(psGTIF, ProjStdParallel2GeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_STANDARD_PARALLEL_2, 0.0));

        GTIFKeySet(psGTIF, ProjNatOriginLatGeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_LATITUDE_OF_CENTER, 0.0));

        GTIFKeySet(psGTIF, ProjNatOriginLongGeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_LONGITUDE_OF_CENTER, 0.0));

        GTIFKeySet(
            psGTIF, ProjFalseEastingGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetProjParm(SRS_PP_FALSE_EASTING, 0.0));

        GTIFKeySet(
            psGTIF, ProjFalseNorthingGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetProjParm(SRS_PP_FALSE_NORTHING, 0.0));
    }

    else if (EQUAL(pszProjection, SRS_PT_POLYCONIC))
    {
        GTIFKeySet(psGTIF, GTModelTypeGeoKey, TYPE_SHORT, 1,
                   ModelTypeProjected);
        GTIFKeySet(psGTIF, ProjectedCSTypeGeoKey, TYPE_SHORT, 1, KvUserDefined);
        GTIFKeySet(psGTIF, ProjectionGeoKey, TYPE_SHORT, 1, KvUserDefined);

        GTIFKeySet(psGTIF, ProjCoordTransGeoKey, TYPE_SHORT, 1, CT_Polyconic);

        GTIFKeySet(psGTIF, ProjNatOriginLatGeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_LATITUDE_OF_ORIGIN, 0.0));

        GTIFKeySet(psGTIF, ProjNatOriginLongGeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_CENTRAL_MERIDIAN, 0.0));

        GTIFKeySet(
            psGTIF, ProjScaleAtNatOriginGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetNormProjParm(SRS_PP_SCALE_FACTOR, 1.0));

        GTIFKeySet(
            psGTIF, ProjFalseEastingGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetProjParm(SRS_PP_FALSE_EASTING, 0.0));

        GTIFKeySet(
            psGTIF, ProjFalseNorthingGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetProjParm(SRS_PP_FALSE_NORTHING, 0.0));
    }

    else if (EQUAL(pszProjection, SRS_PT_AZIMUTHAL_EQUIDISTANT))
    {
        GTIFKeySet(psGTIF, GTModelTypeGeoKey, TYPE_SHORT, 1,
                   ModelTypeProjected);
        GTIFKeySet(psGTIF, ProjectedCSTypeGeoKey, TYPE_SHORT, 1, KvUserDefined);
        GTIFKeySet(psGTIF, ProjectionGeoKey, TYPE_SHORT, 1, KvUserDefined);

        GTIFKeySet(psGTIF, ProjCoordTransGeoKey, TYPE_SHORT, 1,
                   CT_AzimuthalEquidistant);

        GTIFKeySet(psGTIF, ProjCenterLatGeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_LATITUDE_OF_CENTER, 0.0));

        GTIFKeySet(psGTIF, ProjCenterLongGeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_LONGITUDE_OF_CENTER, 0.0));

        GTIFKeySet(
            psGTIF, ProjFalseEastingGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetProjParm(SRS_PP_FALSE_EASTING, 0.0));

        GTIFKeySet(
            psGTIF, ProjFalseNorthingGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetProjParm(SRS_PP_FALSE_NORTHING, 0.0));
    }

    else if (EQUAL(pszProjection, SRS_PT_MILLER_CYLINDRICAL))
    {
        GTIFKeySet(psGTIF, GTModelTypeGeoKey, TYPE_SHORT, 1,
                   ModelTypeProjected);
        GTIFKeySet(psGTIF, ProjectedCSTypeGeoKey, TYPE_SHORT, 1, KvUserDefined);
        GTIFKeySet(psGTIF, ProjectionGeoKey, TYPE_SHORT, 1, KvUserDefined);

        GTIFKeySet(psGTIF, ProjCoordTransGeoKey, TYPE_SHORT, 1,
                   CT_MillerCylindrical);

        GTIFKeySet(psGTIF, ProjCenterLatGeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_LATITUDE_OF_CENTER, 0.0));

        GTIFKeySet(psGTIF, ProjCenterLongGeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_LONGITUDE_OF_CENTER, 0.0));

        GTIFKeySet(
            psGTIF, ProjFalseEastingGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetProjParm(SRS_PP_FALSE_EASTING, 0.0));

        GTIFKeySet(
            psGTIF, ProjFalseNorthingGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetProjParm(SRS_PP_FALSE_NORTHING, 0.0));
    }

    else if (EQUAL(pszProjection, SRS_PT_EQUIRECTANGULAR))
    {
        GTIFKeySet(psGTIF, GTModelTypeGeoKey, TYPE_SHORT, 1,
                   ModelTypeProjected);
        GTIFKeySet(psGTIF, ProjectedCSTypeGeoKey, TYPE_SHORT, 1, KvUserDefined);
        GTIFKeySet(psGTIF, ProjectionGeoKey, TYPE_SHORT, 1, KvUserDefined);

        GTIFKeySet(psGTIF, ProjCoordTransGeoKey, TYPE_SHORT, 1,
                   CT_Equirectangular);

        GTIFKeySet(psGTIF, ProjCenterLatGeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_LATITUDE_OF_ORIGIN, 0.0));

        GTIFKeySet(psGTIF, ProjCenterLongGeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_CENTRAL_MERIDIAN, 0.0));

        GTIFKeySet(psGTIF, ProjStdParallel1GeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_STANDARD_PARALLEL_1, 0.0));

        GTIFKeySet(
            psGTIF, ProjFalseEastingGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetProjParm(SRS_PP_FALSE_EASTING, 0.0));

        GTIFKeySet(
            psGTIF, ProjFalseNorthingGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetProjParm(SRS_PP_FALSE_NORTHING, 0.0));
    }

    else if (EQUAL(pszProjection, SRS_PT_GNOMONIC))
    {
        GTIFKeySet(psGTIF, GTModelTypeGeoKey, TYPE_SHORT, 1,
                   ModelTypeProjected);
        GTIFKeySet(psGTIF, ProjectedCSTypeGeoKey, TYPE_SHORT, 1, KvUserDefined);
        GTIFKeySet(psGTIF, ProjectionGeoKey, TYPE_SHORT, 1, KvUserDefined);

        GTIFKeySet(psGTIF, ProjCoordTransGeoKey, TYPE_SHORT, 1, CT_Gnomonic);

        GTIFKeySet(psGTIF, ProjCenterLatGeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_LATITUDE_OF_ORIGIN, 0.0));

        GTIFKeySet(psGTIF, ProjCenterLongGeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_CENTRAL_MERIDIAN, 0.0));

        GTIFKeySet(
            psGTIF, ProjFalseEastingGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetProjParm(SRS_PP_FALSE_EASTING, 0.0));

        GTIFKeySet(
            psGTIF, ProjFalseNorthingGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetProjParm(SRS_PP_FALSE_NORTHING, 0.0));
    }

    else if (EQUAL(pszProjection, SRS_PT_LAMBERT_AZIMUTHAL_EQUAL_AREA))
    {
        GTIFKeySet(psGTIF, GTModelTypeGeoKey, TYPE_SHORT, 1,
                   ModelTypeProjected);
        GTIFKeySet(psGTIF, ProjectedCSTypeGeoKey, TYPE_SHORT, 1, KvUserDefined);
        GTIFKeySet(psGTIF, ProjectionGeoKey, TYPE_SHORT, 1, KvUserDefined);

        GTIFKeySet(psGTIF, ProjCoordTransGeoKey, TYPE_SHORT, 1,
                   CT_LambertAzimEqualArea);

        GTIFKeySet(psGTIF, ProjCenterLatGeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_LATITUDE_OF_CENTER, 0.0));

        GTIFKeySet(psGTIF, ProjCenterLongGeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_LONGITUDE_OF_CENTER, 0.0));

        GTIFKeySet(
            psGTIF, ProjFalseEastingGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetProjParm(SRS_PP_FALSE_EASTING, 0.0));

        GTIFKeySet(
            psGTIF, ProjFalseNorthingGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetProjParm(SRS_PP_FALSE_NORTHING, 0.0));
    }

    else if (EQUAL(pszProjection, SRS_PT_ORTHOGRAPHIC))
    {
        GTIFKeySet(psGTIF, GTModelTypeGeoKey, TYPE_SHORT, 1,
                   ModelTypeProjected);
        GTIFKeySet(psGTIF, ProjectedCSTypeGeoKey, TYPE_SHORT, 1, KvUserDefined);
        GTIFKeySet(psGTIF, ProjectionGeoKey, TYPE_SHORT, 1, KvUserDefined);

        GTIFKeySet(psGTIF, ProjCoordTransGeoKey, TYPE_SHORT, 1,
                   CT_Orthographic);

        GTIFKeySet(psGTIF, ProjCenterLatGeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_LATITUDE_OF_ORIGIN, 0.0));

        GTIFKeySet(psGTIF, ProjCenterLongGeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_CENTRAL_MERIDIAN, 0.0));

        GTIFKeySet(
            psGTIF, ProjFalseEastingGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetProjParm(SRS_PP_FALSE_EASTING, 0.0));

        GTIFKeySet(
            psGTIF, ProjFalseNorthingGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetProjParm(SRS_PP_FALSE_NORTHING, 0.0));
    }

    else if (EQUAL(pszProjection, SRS_PT_NEW_ZEALAND_MAP_GRID))
    {
        GTIFKeySet(psGTIF, GTModelTypeGeoKey, TYPE_SHORT, 1,
                   ModelTypeProjected);
        GTIFKeySet(psGTIF, ProjectedCSTypeGeoKey, TYPE_SHORT, 1, KvUserDefined);
        GTIFKeySet(psGTIF, ProjectionGeoKey, TYPE_SHORT, 1, KvUserDefined);

        GTIFKeySet(psGTIF, ProjCoordTransGeoKey, TYPE_SHORT, 1,
                   CT_NewZealandMapGrid);

        GTIFKeySet(psGTIF, ProjNatOriginLatGeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_LATITUDE_OF_ORIGIN, 0.0));

        GTIFKeySet(psGTIF, ProjNatOriginLongGeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_CENTRAL_MERIDIAN, 0.0));

        GTIFKeySet(
            psGTIF, ProjFalseEastingGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetProjParm(SRS_PP_FALSE_EASTING, 0.0));

        GTIFKeySet(
            psGTIF, ProjFalseNorthingGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetProjParm(SRS_PP_FALSE_NORTHING, 0.0));
    }

    else if (EQUAL(pszProjection, SRS_PT_ROBINSON))
    {
        GTIFKeySet(psGTIF, GTModelTypeGeoKey, TYPE_SHORT, 1,
                   ModelTypeProjected);
        GTIFKeySet(psGTIF, ProjectedCSTypeGeoKey, TYPE_SHORT, 1, KvUserDefined);
        GTIFKeySet(psGTIF, ProjectionGeoKey, TYPE_SHORT, 1, KvUserDefined);

        GTIFKeySet(psGTIF, ProjCoordTransGeoKey, TYPE_SHORT, 1, CT_Robinson);

        GTIFKeySet(psGTIF, ProjCenterLongGeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_LONGITUDE_OF_CENTER, 0.0));

        GTIFKeySet(
            psGTIF, ProjFalseEastingGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetProjParm(SRS_PP_FALSE_EASTING, 0.0));

        GTIFKeySet(
            psGTIF, ProjFalseNorthingGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetProjParm(SRS_PP_FALSE_NORTHING, 0.0));
    }

    else if (EQUAL(pszProjection, SRS_PT_SINUSOIDAL))
    {
        GTIFKeySet(psGTIF, GTModelTypeGeoKey, TYPE_SHORT, 1,
                   ModelTypeProjected);
        GTIFKeySet(psGTIF, ProjectedCSTypeGeoKey, TYPE_SHORT, 1, KvUserDefined);
        GTIFKeySet(psGTIF, ProjectionGeoKey, TYPE_SHORT, 1, KvUserDefined);

        GTIFKeySet(psGTIF, ProjCoordTransGeoKey, TYPE_SHORT, 1, CT_Sinusoidal);

        GTIFKeySet(psGTIF, ProjCenterLongGeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_LONGITUDE_OF_CENTER, 0.0));

        GTIFKeySet(
            psGTIF, ProjFalseEastingGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetProjParm(SRS_PP_FALSE_EASTING, 0.0));

        GTIFKeySet(
            psGTIF, ProjFalseNorthingGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetProjParm(SRS_PP_FALSE_NORTHING, 0.0));
    }

    else if (EQUAL(pszProjection, SRS_PT_VANDERGRINTEN))
    {
        GTIFKeySet(psGTIF, GTModelTypeGeoKey, TYPE_SHORT, 1,
                   ModelTypeProjected);
        GTIFKeySet(psGTIF, ProjectedCSTypeGeoKey, TYPE_SHORT, 1, KvUserDefined);
        GTIFKeySet(psGTIF, ProjectionGeoKey, TYPE_SHORT, 1, KvUserDefined);

        GTIFKeySet(psGTIF, ProjCoordTransGeoKey, TYPE_SHORT, 1,
                   CT_VanDerGrinten);

        GTIFKeySet(psGTIF, ProjCenterLongGeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_CENTRAL_MERIDIAN, 0.0));

        GTIFKeySet(
            psGTIF, ProjFalseEastingGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetProjParm(SRS_PP_FALSE_EASTING, 0.0));

        GTIFKeySet(
            psGTIF, ProjFalseNorthingGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetProjParm(SRS_PP_FALSE_NORTHING, 0.0));
    }

    else if (EQUAL(pszProjection, SRS_PT_LAMBERT_CONFORMAL_CONIC_2SP))
    {
        GTIFKeySet(psGTIF, GTModelTypeGeoKey, TYPE_SHORT, 1,
                   ModelTypeProjected);
        GTIFKeySet(psGTIF, ProjectedCSTypeGeoKey, TYPE_SHORT, 1, KvUserDefined);
        GTIFKeySet(psGTIF, ProjectionGeoKey, TYPE_SHORT, 1, KvUserDefined);

        GTIFKeySet(psGTIF, ProjCoordTransGeoKey, TYPE_SHORT, 1,
                   CT_LambertConfConic_2SP);

        GTIFKeySet(psGTIF, ProjFalseOriginLatGeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_LATITUDE_OF_ORIGIN, 0.0));

        GTIFKeySet(psGTIF, ProjFalseOriginLongGeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_CENTRAL_MERIDIAN, 0.0));

        GTIFKeySet(psGTIF, ProjStdParallel1GeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_STANDARD_PARALLEL_1, 0.0));

        GTIFKeySet(psGTIF, ProjStdParallel2GeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_STANDARD_PARALLEL_2, 0.0));

        GTIFKeySet(
            psGTIF, ProjFalseOriginEastingGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetProjParm(SRS_PP_FALSE_EASTING, 0.0));

        GTIFKeySet(
            psGTIF, ProjFalseOriginNorthingGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetProjParm(SRS_PP_FALSE_NORTHING, 0.0));
    }

    else if (EQUAL(pszProjection, SRS_PT_LAMBERT_CONFORMAL_CONIC_1SP))
    {
        GTIFKeySet(psGTIF, GTModelTypeGeoKey, TYPE_SHORT, 1,
                   ModelTypeProjected);
        GTIFKeySet(psGTIF, ProjectedCSTypeGeoKey, TYPE_SHORT, 1, KvUserDefined);
        GTIFKeySet(psGTIF, ProjectionGeoKey, TYPE_SHORT, 1, KvUserDefined);

        GTIFKeySet(psGTIF, ProjCoordTransGeoKey, TYPE_SHORT, 1,
                   CT_LambertConfConic_1SP);

        GTIFKeySet(psGTIF, ProjNatOriginLatGeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_LATITUDE_OF_ORIGIN, 0.0));

        GTIFKeySet(psGTIF, ProjNatOriginLongGeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_CENTRAL_MERIDIAN, 0.0));

        GTIFKeySet(
            psGTIF, ProjScaleAtNatOriginGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetNormProjParm(SRS_PP_SCALE_FACTOR, 1.0));

        GTIFKeySet(
            psGTIF, ProjFalseEastingGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetProjParm(SRS_PP_FALSE_EASTING, 0.0));

        GTIFKeySet(
            psGTIF, ProjFalseNorthingGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetProjParm(SRS_PP_FALSE_NORTHING, 0.0));
    }

    else if (EQUAL(pszProjection, SRS_PT_CYLINDRICAL_EQUAL_AREA))
    {
        GTIFKeySet(psGTIF, GTModelTypeGeoKey, TYPE_SHORT, 1,
                   ModelTypeProjected);
        GTIFKeySet(psGTIF, ProjectedCSTypeGeoKey, TYPE_SHORT, 1, KvUserDefined);
        GTIFKeySet(psGTIF, ProjectionGeoKey, TYPE_SHORT, 1, KvUserDefined);

        GTIFKeySet(psGTIF, ProjCoordTransGeoKey, TYPE_SHORT, 1,
                   CT_CylindricalEqualArea);

        GTIFKeySet(psGTIF, ProjNatOriginLongGeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_CENTRAL_MERIDIAN, 0.0));

        GTIFKeySet(psGTIF, ProjStdParallel1GeoKey, TYPE_DOUBLE, 1,
                   poSRSCompatibleOfWKT1->GetNormProjParm(
                       SRS_PP_STANDARD_PARALLEL_1, 0.0));

        GTIFKeySet(
            psGTIF, ProjFalseEastingGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetProjParm(SRS_PP_FALSE_EASTING, 0.0));

        GTIFKeySet(
            psGTIF, ProjFalseNorthingGeoKey, TYPE_DOUBLE, 1,
            poSRSCompatibleOfWKT1->GetProjParm(SRS_PP_FALSE_NORTHING, 0.0));
    }
    else
    {
        bWritePEString = true;
        bUnknownProjection = true;
    }

    // Note that VERTCS is an ESRI "spelling" of VERT_CS so we assume if
    // we find it that we should try to treat this as a PE string.
    if (eFlavor == GEOTIFF_KEYS_ESRI_PE ||
        poSRS->GetAttrValue("VERTCS") != nullptr)
    {
        bWritePEString = true;
    }

    if (nPCS == KvUserDefined)
    {
        const char *pszPROJ4Ext =
            poSRS->GetExtension("PROJCS", "PROJ4", nullptr);
        if (pszPROJ4Ext &&
            strstr(pszPROJ4Ext, "+proj=merc +a=6378137 +b=6378137"))
        {
            bWritePEString = true;
        }
    }

    bWritePEString &=
        CPLTestBool(CPLGetConfigOption("GTIFF_ESRI_CITATION", "YES"));

    bool peStrStored = false;

    if (bWritePEString)
    {
        // Anything we can't map, store as an ESRI PE string with a citation
        // key.
        char *pszPEString = nullptr;
        // We cheat a bit, but if we have a custom_proj4, do not morph to ESRI
        // so as to keep the EXTENSION PROJ4 node
        const char *const apszOptionsDefault[] = {nullptr};
        const char *const apszOptionsEsri[] = {"FORMAT=WKT1_ESRI", nullptr};
        const char *const *papszOptions = apszOptionsDefault;
        if (!(bUnknownProjection &&
              poSRS->GetExtension("PROJCS", "PROJ4", nullptr) != nullptr) &&
            !(poSRS->IsProjected() && !poSRS->IsCompound() &&
              poSRS->GetAxesCount() == 3))
        {
            papszOptions = apszOptionsEsri;
        }
        poSRS->exportToWkt(&pszPEString, papszOptions);
        const int peStrLen = static_cast<int>(strlen(pszPEString));
        if (peStrLen > 0)
        {
            char *outPeStr = static_cast<char *>(
                CPLMalloc(peStrLen + strlen("ESRI PE String = ") + 1));
            strcpy(outPeStr, "ESRI PE String = ");
            strcat(outPeStr, pszPEString);
            oMapAsciiKeys[PCSCitationGeoKey] = outPeStr;
            peStrStored = true;
            CPLFree(outPeStr);
        }
        CPLFree(pszPEString);
        GTIFKeySet(psGTIF, GTModelTypeGeoKey, TYPE_SHORT, 1, KvUserDefined);

        // Not completely sure we really need to imitate ArcGIS to that point
        // but that cannot hurt.
        if (nPCS == 3857)
        {
            oMapAsciiKeys[GTCitationGeoKey] =
                "PCS Name = WGS_1984_Web_Mercator_Auxiliary_Sphere";
            GTIFKeySet(psGTIF, GeographicTypeGeoKey, TYPE_SHORT, 1, GCS_WGS_84);
            GTIFKeySet(psGTIF, GeogSemiMajorAxisGeoKey, TYPE_DOUBLE, 1,
                       6378137.0);
            GTIFKeySet(psGTIF, GeogInvFlatteningGeoKey, TYPE_DOUBLE, 1,
                       298.257223563);
        }
    }

    /* -------------------------------------------------------------------- */
    /*      Is there a false easting/northing set?  If so, write out a      */
    /*      special geokey tag to indicate that GDAL has written these      */
    /*      with the proper interpretation of the linear units.             */
    /* -------------------------------------------------------------------- */
    double dfFE = 0.0;
    double dfFN = 0.0;

    if (eVersion == GEOTIFF_VERSION_1_0 &&
        (GDALGTIFKeyGetDOUBLE(psGTIF, ProjFalseEastingGeoKey, &dfFE, 0, 1) ||
         GDALGTIFKeyGetDOUBLE(psGTIF, ProjFalseNorthingGeoKey, &dfFN, 0, 1) ||
         GDALGTIFKeyGetDOUBLE(psGTIF, ProjFalseOriginEastingGeoKey, &dfFE, 0,
                              1) ||
         GDALGTIFKeyGetDOUBLE(psGTIF, ProjFalseOriginNorthingGeoKey, &dfFN, 0,
                              1)) &&
        (dfFE != 0.0 || dfFN != 0.0) && nUOMLengthCode != 9001)
    {
        GTIFKeySet(psGTIF, ProjLinearUnitsInterpCorrectGeoKey, TYPE_SHORT, 1,
                   static_cast<short>(1));
    }

    /* -------------------------------------------------------------------- */
    /*      Write linear units information.                                 */
    /* -------------------------------------------------------------------- */
    if (poSRS->IsGeocentric())
    {
        GTIFKeySet(psGTIF, GeogLinearUnitsGeoKey, TYPE_SHORT, 1,
                   nUOMLengthCode);
        if (nUOMLengthCode == KvUserDefined)
            GTIFKeySet(psGTIF, GeogLinearUnitSizeGeoKey, TYPE_DOUBLE, 1,
                       dfLinearUOM);
    }
    else if (!poSRS->IsGeographic() &&
             (nPCS == KvUserDefined || eVersion == GEOTIFF_VERSION_1_0))
    {
        GTIFKeySet(psGTIF, ProjLinearUnitsGeoKey, TYPE_SHORT, 1,
                   nUOMLengthCode);
        if (nUOMLengthCode == KvUserDefined)
            GTIFKeySet(psGTIF, ProjLinearUnitSizeGeoKey, TYPE_DOUBLE, 1,
                       dfLinearUOM);

        // If linear units name is available and user defined, store it as
        // citation.
        if (!peStrStored && nUOMLengthCode == KvUserDefined &&
            !osLinearUOMName.empty() &&
            CPLTestBool(CPLGetConfigOption("GTIFF_ESRI_CITATION", "YES")))
        {
            SetLinearUnitCitation(oMapAsciiKeys, osLinearUOMName.c_str());
        }
    }

    /* -------------------------------------------------------------------- */
    /*      Write angular units.                                            */
    /* -------------------------------------------------------------------- */

    const char *angUnitName = "";
    if (bHasEllipsoid &&
        (nGCS == KvUserDefined || eVersion == GEOTIFF_VERSION_1_0))
    {
        double angUnitValue = poSRS->GetAngularUnits(&angUnitName);
        if (EQUAL(angUnitName, "Degree"))
            GTIFKeySet(psGTIF, GeogAngularUnitsGeoKey, TYPE_SHORT, 1,
                       Angular_Degree);
        else if (EQUAL(angUnitName, "arc-second"))
            GTIFKeySet(psGTIF, GeogAngularUnitsGeoKey, TYPE_SHORT, 1,
                       Angular_Arc_Second);
        else if (EQUAL(angUnitName, "arc-minute"))
            GTIFKeySet(psGTIF, GeogAngularUnitsGeoKey, TYPE_SHORT, 1,
                       Angular_Arc_Minute);
        else if (EQUAL(angUnitName, "grad"))
            GTIFKeySet(psGTIF, GeogAngularUnitsGeoKey, TYPE_SHORT, 1,
                       Angular_Grad);
        else if (EQUAL(angUnitName, "gon"))
            GTIFKeySet(psGTIF, GeogAngularUnitsGeoKey, TYPE_SHORT, 1,
                       Angular_Gon);
        else if (EQUAL(angUnitName, "radian"))
            GTIFKeySet(psGTIF, GeogAngularUnitsGeoKey, TYPE_SHORT, 1,
                       Angular_Radian);
        // else if (EQUAL(angUnitName, "microradian"))
        //    GTIFKeySet(psGTIF, GeogAngularUnitsGeoKey, TYPE_SHORT, 1,
        //               9109);
        else
        {
            // GeogCitationGeoKey may be rewritten if the gcs is user defined.
            oMapAsciiKeys[GeogCitationGeoKey] = angUnitName;
            GTIFKeySet(psGTIF, GeogAngularUnitSizeGeoKey, TYPE_DOUBLE, 1,
                       angUnitValue);
        }
    }

    /* -------------------------------------------------------------------- */
    /*      Try to write a citation from the main coordinate system         */
    /*      name.                                                           */
    /* -------------------------------------------------------------------- */
    if (poSRS->GetName() != nullptr &&
        ((poSRS->IsProjected() &&
          (nPCS == KvUserDefined || eVersion == GEOTIFF_VERSION_1_0)) ||
         poSRS->IsCompound() || poSRS->IsLocal() ||
         (poSRS->IsGeocentric() &&
          (nGCS == KvUserDefined || eVersion == GEOTIFF_VERSION_1_0))))
    {
        if (!(bWritePEString && nPCS == 3857))
        {
            oMapAsciiKeys[GTCitationGeoKey] = poSRS->GetName();
        }
    }

    /* -------------------------------------------------------------------- */
    /*      Try to write a GCS citation.                                    */
    /* -------------------------------------------------------------------- */
    if (nGCS == KvUserDefined || eVersion == GEOTIFF_VERSION_1_0)
    {
        const OGR_SRSNode *poGCS = poSRS->GetAttrNode("GEOGCS");

        if (poGCS != nullptr && poGCS->GetChild(0) != nullptr)
        {
            oMapAsciiKeys[GeogCitationGeoKey] = poGCS->GetChild(0)->GetValue();
        }
    }

    /* -------------------------------------------------------------------- */
    /*      Try to identify the GCS/datum, scanning the EPSG datum file for */
    /*      a match.                                                        */
    /* -------------------------------------------------------------------- */
    if (nPCS == KvUserDefined)
    {
        if (nGCS == KvUserDefined)
        {
            if (nDatum == Datum_North_American_Datum_1927)
                nGCS = GCS_NAD27;
            else if (nDatum == Datum_North_American_Datum_1983)
                nGCS = GCS_NAD83;
            else if (nDatum == Datum_WGS84 || nDatum == DatumE_WGS84)
                nGCS = GCS_WGS_84;
        }

        if (nGCS != KvUserDefined)
        {
            GTIFKeySet(psGTIF, GeographicTypeGeoKey, TYPE_SHORT, 1, nGCS);
        }
        else if (nDatum != KvUserDefined)
        {
            GTIFKeySet(psGTIF, GeographicTypeGeoKey, TYPE_SHORT, 1,
                       KvUserDefined);
            GTIFKeySet(psGTIF, GeogGeodeticDatumGeoKey, TYPE_SHORT, 1, nDatum);
        }
        else if (nSpheroid != KvUserDefined)
        {
            GTIFKeySet(psGTIF, GeographicTypeGeoKey, TYPE_SHORT, 1,
                       KvUserDefined);
            GTIFKeySet(psGTIF, GeogGeodeticDatumGeoKey, TYPE_SHORT, 1,
                       KvUserDefined);
            GTIFKeySet(psGTIF, GeogEllipsoidGeoKey, TYPE_SHORT, 1, nSpheroid);
        }
        else if (dfSemiMajor != 0.0)
        {
            GTIFKeySet(psGTIF, GeographicTypeGeoKey, TYPE_SHORT, 1,
                       KvUserDefined);
            GTIFKeySet(psGTIF, GeogGeodeticDatumGeoKey, TYPE_SHORT, 1,
                       KvUserDefined);
            GTIFKeySet(psGTIF, GeogEllipsoidGeoKey, TYPE_SHORT, 1,
                       KvUserDefined);
            GTIFKeySet(psGTIF, GeogSemiMajorAxisGeoKey, TYPE_DOUBLE, 1,
                       dfSemiMajor);
            if (dfInvFlattening == 0.0)
                GTIFKeySet(psGTIF, GeogSemiMinorAxisGeoKey, TYPE_DOUBLE, 1,
                           dfSemiMajor);
            else
                GTIFKeySet(psGTIF, GeogInvFlatteningGeoKey, TYPE_DOUBLE, 1,
                           dfInvFlattening);
        }
        else if (poSRS->GetAttrValue("DATUM") != nullptr &&
                 strstr(poSRS->GetAttrValue("DATUM"), "unknown") == nullptr &&
                 strstr(poSRS->GetAttrValue("DATUM"), "unnamed") == nullptr)

        {
            CPLError(CE_Warning, CPLE_AppDefined,
                     "Couldn't translate `%s' to a GeoTIFF datum.",
                     poSRS->GetAttrValue("DATUM"));
        }

        if (nGCS == KvUserDefined || eVersion == GEOTIFF_VERSION_1_0)
        {
            // Always set InvFlattening if it is available.
            // So that it doesn't need to calculate from SemiMinor.
            if (dfInvFlattening != 0.0)
                GTIFKeySet(psGTIF, GeogInvFlatteningGeoKey, TYPE_DOUBLE, 1,
                           dfInvFlattening);
            // Always set SemiMajor to keep the precision and in case of
            // editing.
            if (dfSemiMajor != 0.0)
                GTIFKeySet(psGTIF, GeogSemiMajorAxisGeoKey, TYPE_DOUBLE, 1,
                           dfSemiMajor);

            if (nGCS == KvUserDefined &&
                CPLTestBool(CPLGetConfigOption("GTIFF_ESRI_CITATION", "YES")))
            {
                SetGeogCSCitation(psGTIF, oMapAsciiKeys, poSRS, angUnitName,
                                  nDatum, nSpheroid);
            }
        }
    }

/* -------------------------------------------------------------------- */
/*      Do we have TOWGS84 parameters?                                  */
/* -------------------------------------------------------------------- */
#if !defined(GEO_NORMALIZE_DISABLE_TOWGS84)
    double adfTOWGS84[7] = {0.0};

    if ((nGCS == KvUserDefined || eVersion == GEOTIFF_VERSION_1_0) &&
        poSRS->GetTOWGS84(adfTOWGS84) == OGRERR_NONE)
    {
        // If we are writing a SRS with a EPSG code, and that the EPSG code
        // of the current SRS object and the one coming from the EPSG code
        // are the same, then by default, do not write them.
        bool bUseReferenceTOWGS84 = false;
        const char *pszAuthName = poSRS->GetAuthorityName(nullptr);
        const char *pszAuthCode = poSRS->GetAuthorityCode(nullptr);
        if (pszAuthName && EQUAL(pszAuthName, "EPSG") && pszAuthCode)
        {
            CPLErrorHandlerPusher oErrorHandler(CPLQuietErrorHandler);
            OGRSpatialReference oRefSRS;
            double adfRefTOWGS84[7] = {0.0};
            if (oRefSRS.importFromEPSG(atoi(pszAuthCode)) == OGRERR_NONE)
            {
                oRefSRS.AddGuessedTOWGS84();
                if (oRefSRS.GetTOWGS84(adfRefTOWGS84) == OGRERR_NONE &&
                    memcmp(adfRefTOWGS84, adfTOWGS84, sizeof(adfTOWGS84)) == 0)
                {
                    bUseReferenceTOWGS84 = true;
                }
            }
        }
        const char *pszWriteTOWGS84 =
            CPLGetConfigOption("GTIFF_WRITE_TOWGS84", "AUTO");
        if ((EQUAL(pszWriteTOWGS84, "YES") || EQUAL(pszWriteTOWGS84, "TRUE") ||
             EQUAL(pszWriteTOWGS84, "ON")) ||
            (!bUseReferenceTOWGS84 && EQUAL(pszWriteTOWGS84, "AUTO")))
        {
            if (adfTOWGS84[3] == 0.0 && adfTOWGS84[4] == 0.0 &&
                adfTOWGS84[5] == 0.0 && adfTOWGS84[6] == 0.0)
            {
                if (nGCS == GCS_WGS_84 && adfTOWGS84[0] == 0.0 &&
                    adfTOWGS84[1] == 0.0 && adfTOWGS84[2] == 0.0)
                {
                    ;  // Do nothing.
                }
                else
                    GTIFKeySet(psGTIF, GeogTOWGS84GeoKey, TYPE_DOUBLE, 3,
                               adfTOWGS84);
            }
            else
                GTIFKeySet(psGTIF, GeogTOWGS84GeoKey, TYPE_DOUBLE, 7,
                           adfTOWGS84);
        }
    }
#endif

    /* -------------------------------------------------------------------- */
    /*      Do we have vertical information to set?                         */
    /* -------------------------------------------------------------------- */
    if (poSRS->GetAttrValue("COMPD_CS|VERT_CS") != nullptr)
    {
        bool bGotVertCSCode = false;
        const char *pszValue = poSRS->GetAuthorityCode("COMPD_CS|VERT_CS");
        if (pszValue && atoi(pszValue))
        {
            bGotVertCSCode = true;
            GTIFKeySet(psGTIF, VerticalCSTypeGeoKey, TYPE_SHORT, 1,
                       atoi(pszValue));
        }

        if (eVersion == GEOTIFF_VERSION_1_0 || !bGotVertCSCode)
        {
            oMapAsciiKeys[VerticalCitationGeoKey] =
                poSRS->GetAttrValue("COMPD_CS|VERT_CS");

            pszValue = poSRS->GetAuthorityCode("COMPD_CS|VERT_CS|VERT_DATUM");
            if (pszValue && atoi(pszValue))
                GTIFKeySet(psGTIF, VerticalDatumGeoKey, TYPE_SHORT, 1,
                           atoi(pszValue));

            pszValue = poSRS->GetAuthorityCode("COMPD_CS|VERT_CS|UNIT");
            if (pszValue && atoi(pszValue))
                GTIFKeySet(psGTIF, VerticalUnitsGeoKey, TYPE_SHORT, 1,
                           atoi(pszValue));
        }
    }
    else if (eVersion >= GEOTIFF_VERSION_1_1 && nVerticalCSKeyValue != 0)
    {
        GTIFKeySet(psGTIF, VerticalCSTypeGeoKey, TYPE_SHORT, 1,
                   nVerticalCSKeyValue);
    }

    const double dfCoordinateEpoch = poSRS->GetCoordinateEpoch();
    if (dfCoordinateEpoch > 0)
    {
        GTIFKeySet(psGTIF, CoordinateEpochGeoKey, TYPE_DOUBLE, 1,
                   dfCoordinateEpoch);
    }

    /* -------------------------------------------------------------------- */
    /*      Write all ascii keys                                            */
    /* -------------------------------------------------------------------- */
    for (const auto &oIter : oMapAsciiKeys)
    {
        GTIFKeySet(psGTIF, oIter.first, TYPE_ASCII, 0, oIter.second.c_str());
    }

    return TRUE;
}

/************************************************************************/
/*                         GTIFWktFromMemBuf()                          */
/************************************************************************/

CPLErr GTIFWktFromMemBuf(int nSize, unsigned char *pabyBuffer, char **ppszWKT,
                         double *padfGeoTransform, int *pnGCPCount,
                         GDAL_GCP **ppasGCPList)
{
    OGRSpatialReferenceH hSRS = nullptr;
    if (ppszWKT)
        *ppszWKT = nullptr;
    CPLErr eErr =
        GTIFWktFromMemBufEx(nSize, pabyBuffer, &hSRS, padfGeoTransform,
                            pnGCPCount, ppasGCPList, nullptr, nullptr);
    if (eErr == CE_None)
    {
        if (hSRS && ppszWKT)
        {
            OSRExportToWkt(hSRS, ppszWKT);
        }
    }
    OSRDestroySpatialReference(hSRS);
    return eErr;
}

CPLErr GTIFWktFromMemBufEx(int nSize, unsigned char *pabyBuffer,
                           OGRSpatialReferenceH *phSRS,
                           double *padfGeoTransform, int *pnGCPCount,
                           GDAL_GCP **ppasGCPList, int *pbPixelIsPoint,
                           char ***ppapszRPCMD)

{
    char szFilename[100] = {};

    snprintf(szFilename, sizeof(szFilename), "/vsimem/wkt_from_mem_buf_%ld.tif",
             static_cast<long>(CPLGetPID()));

    /* -------------------------------------------------------------------- */
    /*      Initialization of libtiff and libgeotiff.                       */
    /* -------------------------------------------------------------------- */
    GTiffOneTimeInit();  // For RPC tag.
    LibgeotiffOneTimeInit();

    /* -------------------------------------------------------------------- */
    /*      Create a memory file from the buffer.                           */
    /* -------------------------------------------------------------------- */
    VSILFILE *fp = VSIFileFromMemBuffer(szFilename, pabyBuffer, nSize, FALSE);
    if (fp == nullptr)
        return CE_Failure;

    /* -------------------------------------------------------------------- */
    /*      Initialize access to the memory geotiff structure.              */
    /* -------------------------------------------------------------------- */
    TIFF *hTIFF = VSI_TIFFOpen(szFilename, "rc", fp);

    if (hTIFF == nullptr)
    {
        CPLError(CE_Failure, CPLE_AppDefined,
                 "TIFF/GeoTIFF structure is corrupt.");
        VSIUnlink(szFilename);
        CPL_IGNORE_RET_VAL(VSIFCloseL(fp));
        return CE_Failure;
    }

    /* -------------------------------------------------------------------- */
    /*      Get the projection definition.                                  */
    /* -------------------------------------------------------------------- */
    bool bPixelIsPoint = false;
    bool bPointGeoIgnore = false;
    unsigned short nRasterType = 0;

    GTIF *hGTIF = GTIFNew(hTIFF);
    if (hGTIF)
        GTIFAttachPROJContext(hGTIF, OSRGetProjTLSContext());

    if (hGTIF != nullptr &&
        GDALGTIFKeyGetSHORT(hGTIF, GTRasterTypeGeoKey, &nRasterType, 0, 1) ==
            1 &&
        nRasterType == static_cast<unsigned short>(RasterPixelIsPoint))
    {
        bPixelIsPoint = true;
        bPointGeoIgnore =
            CPLTestBool(CPLGetConfigOption("GTIFF_POINT_GEO_IGNORE", "FALSE"));
    }
    if (pbPixelIsPoint)
        *pbPixelIsPoint = bPixelIsPoint;
    if (ppapszRPCMD)
        *ppapszRPCMD = nullptr;

    if (phSRS)
    {
        *phSRS = nullptr;
        if (hGTIF != nullptr)
        {
            GTIFDefn *psGTIFDefn = GTIFAllocDefn();
            if (GTIFGetDefn(hGTIF, psGTIFDefn))
            {
                *phSRS = GTIFGetOGISDefnAsOSR(hGTIF, psGTIFDefn);
            }
            GTIFFreeDefn(psGTIFDefn);
        }
    }
    if (hGTIF)
        GTIFFree(hGTIF);

    /* -------------------------------------------------------------------- */
    /*      Get geotransform or tiepoints.                                  */
    /* -------------------------------------------------------------------- */
    double *padfTiePoints = nullptr;
    double *padfScale = nullptr;
    double *padfMatrix = nullptr;
    int16_t nCount = 0;

    padfGeoTransform[0] = 0.0;
    padfGeoTransform[1] = 1.0;
    padfGeoTransform[2] = 0.0;
    padfGeoTransform[3] = 0.0;
    padfGeoTransform[4] = 0.0;
    padfGeoTransform[5] = 1.0;

    *pnGCPCount = 0;
    *ppasGCPList = nullptr;

    if (TIFFGetField(hTIFF, TIFFTAG_GEOPIXELSCALE, &nCount, &padfScale) &&
        nCount >= 2)
    {
        padfGeoTransform[1] = padfScale[0];
        padfGeoTransform[5] = -std::abs(padfScale[1]);

        if (TIFFGetField(hTIFF, TIFFTAG_GEOTIEPOINTS, &nCount,
                         &padfTiePoints) &&
            nCount >= 6)
        {
            padfGeoTransform[0] =
                padfTiePoints[3] - padfTiePoints[0] * padfGeoTransform[1];
            padfGeoTransform[3] =
                padfTiePoints[4] - padfTiePoints[1] * padfGeoTransform[5];

            // Adjust for pixel is point in transform.
            if (bPixelIsPoint && !bPointGeoIgnore)
            {
                padfGeoTransform[0] -=
                    padfGeoTransform[1] * 0.5 + padfGeoTransform[2] * 0.5;
                padfGeoTransform[3] -=
                    padfGeoTransform[4] * 0.5 + padfGeoTransform[5] * 0.5;
            }
        }
    }
    else if (TIFFGetField(hTIFF, TIFFTAG_GEOTIEPOINTS, &nCount,
                          &padfTiePoints) &&
             nCount >= 6)
    {
        *pnGCPCount = nCount / 6;
        *ppasGCPList =
            static_cast<GDAL_GCP *>(CPLCalloc(sizeof(GDAL_GCP), *pnGCPCount));

        for (int iGCP = 0; iGCP < *pnGCPCount; iGCP++)
        {
            char szID[32] = {};
            GDAL_GCP *psGCP = *ppasGCPList + iGCP;

            snprintf(szID, sizeof(szID), "%d", iGCP + 1);
            psGCP->pszId = CPLStrdup(szID);
            psGCP->pszInfo = CPLStrdup("");
            psGCP->dfGCPPixel = padfTiePoints[iGCP * 6 + 0];
            psGCP->dfGCPLine = padfTiePoints[iGCP * 6 + 1];
            psGCP->dfGCPX = padfTiePoints[iGCP * 6 + 3];
            psGCP->dfGCPY = padfTiePoints[iGCP * 6 + 4];
            psGCP->dfGCPZ = padfTiePoints[iGCP * 6 + 5];
        }
    }
    else if (TIFFGetField(hTIFF, TIFFTAG_GEOTRANSMATRIX, &nCount,
                          &padfMatrix) &&
             nCount == 16)
    {
        padfGeoTransform[0] = padfMatrix[3];
        padfGeoTransform[1] = padfMatrix[0];
        padfGeoTransform[2] = padfMatrix[1];
        padfGeoTransform[3] = padfMatrix[7];
        padfGeoTransform[4] = padfMatrix[4];
        padfGeoTransform[5] = padfMatrix[5];
    }

    /* -------------------------------------------------------------------- */
    /*      Read RPC                                                        */
    /* -------------------------------------------------------------------- */
    if (ppapszRPCMD != nullptr)
    {
        *ppapszRPCMD = GTiffDatasetReadRPCTag(hTIFF);
    }

    /* -------------------------------------------------------------------- */
    /*      Cleanup.                                                        */
    /* -------------------------------------------------------------------- */
    XTIFFClose(hTIFF);
    CPL_IGNORE_RET_VAL(VSIFCloseL(fp));

    VSIUnlink(szFilename);

    if (phSRS && *phSRS == nullptr)
        return CE_Failure;

    return CE_None;
}

/************************************************************************/
/*                         GTIFMemBufFromWkt()                          */
/************************************************************************/

CPLErr GTIFMemBufFromWkt(const char *pszWKT, const double *padfGeoTransform,
                         int nGCPCount, const GDAL_GCP *pasGCPList, int *pnSize,
                         unsigned char **ppabyBuffer)
{
    OGRSpatialReference oSRS;
    if (pszWKT != nullptr)
        oSRS.importFromWkt(pszWKT);
    return GTIFMemBufFromSRS(OGRSpatialReference::ToHandle(&oSRS),
                             padfGeoTransform, nGCPCount, pasGCPList, pnSize,
                             ppabyBuffer, FALSE, nullptr);
}

CPLErr GTIFMemBufFromSRS(OGRSpatialReferenceH hSRS,
                         const double *padfGeoTransform, int nGCPCount,
                         const GDAL_GCP *pasGCPList, int *pnSize,
                         unsigned char **ppabyBuffer, int bPixelIsPoint,
                         char **papszRPCMD)

{
    char szFilename[100] = {};

    snprintf(szFilename, sizeof(szFilename), "/vsimem/wkt_from_mem_buf_%ld.tif",
             static_cast<long>(CPLGetPID()));

    /* -------------------------------------------------------------------- */
    /*      Initialization of libtiff and libgeotiff.                       */
    /* -------------------------------------------------------------------- */
    GTiffOneTimeInit();  // For RPC tag.
    LibgeotiffOneTimeInit();

    /* -------------------------------------------------------------------- */
    /*      Initialize access to the memory geotiff structure.              */
    /* -------------------------------------------------------------------- */
    VSILFILE *fpL = VSIFOpenL(szFilename, "w");
    if (fpL == nullptr)
        return CE_Failure;

    TIFF *hTIFF = VSI_TIFFOpen(szFilename, "w", fpL);

    if (hTIFF == nullptr)
    {
        CPLError(CE_Failure, CPLE_AppDefined,
                 "TIFF/GeoTIFF structure is corrupt.");
        CPL_IGNORE_RET_VAL(VSIFCloseL(fpL));
        return CE_Failure;
    }

    /* -------------------------------------------------------------------- */
    /*      Write some minimal set of image parameters.                     */
    /* -------------------------------------------------------------------- */
    TIFFSetField(hTIFF, TIFFTAG_IMAGEWIDTH, 1);
    TIFFSetField(hTIFF, TIFFTAG_IMAGELENGTH, 1);
    TIFFSetField(hTIFF, TIFFTAG_BITSPERSAMPLE, 8);
    TIFFSetField(hTIFF, TIFFTAG_SAMPLESPERPIXEL, 1);
    TIFFSetField(hTIFF, TIFFTAG_ROWSPERSTRIP, 1);
    TIFFSetField(hTIFF, TIFFTAG_PLANARCONFIG, PLANARCONFIG_CONTIG);
    TIFFSetField(hTIFF, TIFFTAG_PHOTOMETRIC, PHOTOMETRIC_MINISBLACK);

    /* -------------------------------------------------------------------- */
    /*      Get the projection definition.                                  */
    /* -------------------------------------------------------------------- */

    bool bPointGeoIgnore = false;
    if (bPixelIsPoint)
    {
        bPointGeoIgnore =
            CPLTestBool(CPLGetConfigOption("GTIFF_POINT_GEO_IGNORE", "FALSE"));
    }

    GTIF *hGTIF = nullptr;
    if (hSRS != nullptr || bPixelIsPoint)
    {
        hGTIF = GTIFNew(hTIFF);
        if (hGTIF)
            GTIFAttachPROJContext(hGTIF, OSRGetProjTLSContext());

        if (hSRS != nullptr)
            GTIFSetFromOGISDefnEx(hGTIF, hSRS, GEOTIFF_KEYS_STANDARD,
                                  GEOTIFF_VERSION_1_0);

        if (bPixelIsPoint)
        {
            GTIFKeySet(hGTIF, GTRasterTypeGeoKey, TYPE_SHORT, 1,
                       RasterPixelIsPoint);
        }

        GTIFWriteKeys(hGTIF);
        GTIFFree(hGTIF);
    }

    /* -------------------------------------------------------------------- */
    /*      Set the geotransform, or GCPs.                                  */
    /* -------------------------------------------------------------------- */

    if (padfGeoTransform[0] != 0.0 || padfGeoTransform[1] != 1.0 ||
        padfGeoTransform[2] != 0.0 || padfGeoTransform[3] != 0.0 ||
        padfGeoTransform[4] != 0.0 || std::abs(padfGeoTransform[5]) != 1.0)
    {

        if (padfGeoTransform[2] == 0.0 && padfGeoTransform[4] == 0.0)
        {
            double adfPixelScale[3] = {padfGeoTransform[1],
                                       fabs(padfGeoTransform[5]), 0.0};

            TIFFSetField(hTIFF, TIFFTAG_GEOPIXELSCALE, 3, adfPixelScale);

            double adfTiePoints[6] = {
                0.0, 0.0, 0.0, padfGeoTransform[0], padfGeoTransform[3], 0.0};

            if (bPixelIsPoint && !bPointGeoIgnore)
            {
                adfTiePoints[3] +=
                    padfGeoTransform[1] * 0.5 + padfGeoTransform[2] * 0.5;
                adfTiePoints[4] +=
                    padfGeoTransform[4] * 0.5 + padfGeoTransform[5] * 0.5;
            }

            TIFFSetField(hTIFF, TIFFTAG_GEOTIEPOINTS, 6, adfTiePoints);
        }
        else
        {
            double adfMatrix[16] = {0.0};

            adfMatrix[0] = padfGeoTransform[1];
            adfMatrix[1] = padfGeoTransform[2];
            adfMatrix[3] = padfGeoTransform[0];
            adfMatrix[4] = padfGeoTransform[4];
            adfMatrix[5] = padfGeoTransform[5];
            adfMatrix[7] = padfGeoTransform[3];
            adfMatrix[15] = 1.0;

            if (bPixelIsPoint && !bPointGeoIgnore)
            {
                adfMatrix[3] +=
                    padfGeoTransform[1] * 0.5 + padfGeoTransform[2] * 0.5;
                adfMatrix[7] +=
                    padfGeoTransform[4] * 0.5 + padfGeoTransform[5] * 0.5;
            }

            TIFFSetField(hTIFF, TIFFTAG_GEOTRANSMATRIX, 16, adfMatrix);
        }
    }

    /* -------------------------------------------------------------------- */
    /*      Otherwise write tiepoints if they are available.                */
    /* -------------------------------------------------------------------- */
    else if (nGCPCount > 0)
    {
        double *padfTiePoints =
            static_cast<double *>(CPLMalloc(6 * sizeof(double) * nGCPCount));

        for (int iGCP = 0; iGCP < nGCPCount; iGCP++)
        {

            padfTiePoints[iGCP * 6 + 0] = pasGCPList[iGCP].dfGCPPixel;
            padfTiePoints[iGCP * 6 + 1] = pasGCPList[iGCP].dfGCPLine;
            padfTiePoints[iGCP * 6 + 2] = 0;
            padfTiePoints[iGCP * 6 + 3] = pasGCPList[iGCP].dfGCPX;
            padfTiePoints[iGCP * 6 + 4] = pasGCPList[iGCP].dfGCPY;
            padfTiePoints[iGCP * 6 + 5] = pasGCPList[iGCP].dfGCPZ;
        }

        TIFFSetField(hTIFF, TIFFTAG_GEOTIEPOINTS, 6 * nGCPCount, padfTiePoints);
        CPLFree(padfTiePoints);
    }

    /* -------------------------------------------------------------------- */
    /*      Write RPC                                                       */
    /* -------------------------------------------------------------------- */
    if (papszRPCMD != nullptr)
    {
        GTiffDatasetWriteRPCTag(hTIFF, papszRPCMD);
    }

    /* -------------------------------------------------------------------- */
    /*      Cleanup and return the created memory buffer.                   */
    /* -------------------------------------------------------------------- */
    GByte bySmallImage = 0;

    TIFFWriteEncodedStrip(hTIFF, 0, reinterpret_cast<char *>(&bySmallImage), 1);
    TIFFWriteCheck(hTIFF, TIFFIsTiled(hTIFF), "GTIFMemBufFromWkt");
    TIFFWriteDirectory(hTIFF);

    XTIFFClose(hTIFF);
    CPL_IGNORE_RET_VAL(VSIFCloseL(fpL));

    /* -------------------------------------------------------------------- */
    /*      Read back from the memory buffer.  It would be preferable       */
    /*      to be able to "steal" the memory buffer, but there isn't        */
    /*      currently any support for this.                                 */
    /* -------------------------------------------------------------------- */
    GUIntBig nBigLength = 0;

    *ppabyBuffer = VSIGetMemFileBuffer(szFilename, &nBigLength, TRUE);
    *pnSize = static_cast<int>(nBigLength);

    return CE_None;
}
