ossimGeoidEgm96 Class Reference

#include <ossimGeoidEgm96.h>

Inheritance diagram for ossimGeoidEgm96:

Public Member Functions
	ossimGeoidEgm96 ()
	ossimGeoidEgm96 (const ossimFilename &grid_file, ossimByteOrder byteOrder=OSSIM_BIG_ENDIAN)
virtual	~ossimGeoidEgm96 ()
virtual bool	open (const ossimFilename &grid_file, ossimByteOrder byteOrder=OSSIM_BIG_ENDIAN)
virtual ossimString	getShortName () const
virtual double	offsetFromEllipsoid (const ossimGpt &gpt)
double	geoidToEllipsoidHeight (double lat, double lon, double geoidHeight)
double	ellipsoidToGeoidHeight (double lat, double lon, double ellipsoidHeight)
Public Member Functions inherited from ossimGeoid
	ossimGeoid ()
Public Member Functions inherited from ossimObject
	ossimObject ()
virtual	~ossimObject ()
virtual ossimObject *	dup () const
virtual ossimString	getLongName () const
virtual ossimString	getDescription () const
virtual ossimString	getClassName () const
virtual RTTItypeid	getType () const
virtual bool	canCastTo (ossimObject *obj) const
virtual bool	canCastTo (const RTTItypeid &id) const
virtual bool	canCastTo (const ossimString &parentClassName) const
virtual bool	saveState (ossimKeywordlist &kwl, const char *prefix=0) const
virtual bool	loadState (const ossimKeywordlist &kwl, const char *prefix=0)
virtual std::ostream &	print (std::ostream &out) const
	Generic print method. More...
virtual bool	isEqualTo (const ossimObject &obj, ossimCompareType compareType=OSSIM_COMPARE_FULL) const
virtual void	accept (ossimVisitor &visitor)
Public Member Functions inherited from ossimReferenced
	ossimReferenced ()
	ossimReferenced (const ossimReferenced &)
ossimReferenced &	operator= (const ossimReferenced &)
void	ref () const
	increment the reference count by one, indicating that this object has another pointer which is referencing it. More...
void	unref () const
	decrement the reference count by one, indicating that a pointer to this object is referencing it. More...
void	unref_nodelete () const
	decrement the reference count by one, indicating that a pointer to this object is referencing it. More...
int	referenceCount () const
Public Member Functions inherited from ossimErrorStatusInterface
	ossimErrorStatusInterface ()
virtual	~ossimErrorStatusInterface ()
virtual ossimErrorCode	getErrorStatus () const
virtual ossimString	getErrorStatusString () const
virtual void	setErrorStatus (ossimErrorCode error_status) const
virtual void	setErrorStatus () const
virtual void	clearErrorStatus () const
bool	hasError () const
virtual std::ostream &	print (std::ostream &out) const
	Outputs theErrorStatus as an ossimErrorCode and an ossimString. More...

Protected Attributes
std::vector< float >	theGeoidHeightBuffer
float *	theGeoidHeightBufferPtr
Protected Attributes inherited from ossimErrorStatusInterface
ossimErrorCode	theErrorStatus

Additional Inherited Members
Protected Member Functions inherited from ossimGeoid
virtual	~ossimGeoid ()
Protected Member Functions inherited from ossimReferenced
virtual	~ossimReferenced ()

Detailed Description

Definition at line 30 of file ossimGeoidEgm96.h.

Constructor & Destructor Documentation

ossimGeoidEgm96() [1/2]

ossimGeoidEgm96::ossimGeoidEgm96

(

)

Definition at line 33 of file ossimGeoidEgm96.cpp.

   :theGeoidHeightBufferPtr(0)
{
}

ossimGeoidEgm96() [2/2]

ossimGeoidEgm96::ossimGeoidEgm96	(	const ossimFilename &	grid_file,
		ossimByteOrder	byteOrder = OSSIM_BIG_ENDIAN
	)

Definition at line 38 of file ossimGeoidEgm96.cpp.

References ossim::byteOrder(), ossimErrorStatusInterface::getErrorStatus(), open(), ossimErrorCodes::OSSIM_OK, and theGeoidHeightBuffer.

   :theGeoidHeightBufferPtr(0)
{
   open(grid_file, byteOrder);
   if (getErrorStatus() != ossimErrorCodes::OSSIM_OK)
   {
      theGeoidHeightBuffer.clear();
   }
}

~ossimGeoidEgm96()

ossimGeoidEgm96::~ossimGeoidEgm96 ( )

virtual

Definition at line 49 of file ossimGeoidEgm96.cpp.

{
}

Member Function Documentation

ellipsoidToGeoidHeight()

double ossimGeoidEgm96::ellipsoidToGeoidHeight	(	double	lat,
		double	lon,
		double	ellipsoidHeight
	)

Definition at line 304 of file ossimGeoidEgm96.cpp.

References ossim::isnan(), and offsetFromEllipsoid().

{
   ossimGpt gpt(lat, lon);
   double height = offsetFromEllipsoid(gpt);
   if (!ossim::isnan(height))
   {
      return (ellipsoidHeight - height);
   }
   return height; // nan
}

geoidToEllipsoidHeight()

double ossimGeoidEgm96::geoidToEllipsoidHeight	(	double	lat,
		double	lon,
		double	geoidHeight
	)

Definition at line 291 of file ossimGeoidEgm96.cpp.

References ossim::isnan(), and offsetFromEllipsoid().

{
   ossimGpt gpt(lat, lon);
   double height = offsetFromEllipsoid(gpt);
   if (!ossim::isnan(height))
   {
      height += geoidHeight;
   }
   return height;
}

getShortName()

ossimString ossimGeoidEgm96::getShortName ( ) const

virtual

Reimplemented from ossimObject.

Definition at line 53 of file ossimGeoidEgm96.cpp.

{
   return "geoid1996";
}

offsetFromEllipsoid()

double ossimGeoidEgm96::offsetFromEllipsoid ( const ossimGpt &  gpt )

virtual

Returns

The offset from the ellipsoid to the geoid or ossim::nan() (IEEE NAN) if grid does not contain the point.

Implements ossimGeoid.

Definition at line 170 of file ossimGeoidEgm96.cpp.

References ossimGpt::changeDatum(), ossimDatumFactory::instance(), ossim::nan(), and theGeoidHeightBufferPtr.

Referenced by ellipsoidToGeoidHeight(), and geoidToEllipsoidHeight().

{
   double offset = ossim::nan();
   ossimGpt savedGpt = gpt;
   if(ossimDatumFactory::instance()->wgs84())
   {
      savedGpt.changeDatum(ossimDatumFactory::instance()->wgs84());
   }
   
   if (!theGeoidHeightBufferPtr)
   {
      if(traceDebug())
      {
         ossimNotify(ossimNotifyLevel_FATAL)
            << "ossimGeoidEgm96::offsetFromEllipsoid, "
            << "Object not initialized!\n";
      }

      return offset;
   }
   
   long    Index;
   double DeltaX, DeltaY;
   double ElevationSE, ElevationSW, ElevationNE, ElevationNW;
   double LatitudeDD, LongitudeDD;
   double OffsetX, OffsetY;
   double PostX, PostY;
   double UpperY, LowerY;

   LatitudeDD  = savedGpt.latd();
   
   // Check for wrap.
   if (LatitudeDD < -90.0)
   {
      LatitudeDD = -180.0 - LatitudeDD;
   }
   else if (LatitudeDD > 90.0)
   {
      LatitudeDD = 180.0 - LatitudeDD;
   }

   if ( (LatitudeDD < -90.0) || LatitudeDD > 90.0)
   {
      if(traceDebug())
      {
         // Latitude out of range
         ossimNotify(ossimNotifyLevel_FATAL)
            << "FATAL: " << "ossimGeoidEgm96::offsetFromEllipsoid, "
            << "Point out of range:  " << savedGpt << "\n";
      }
      return offset;
   }
   
   LongitudeDD = savedGpt.lond();

   // Check for wrap.
   if (LongitudeDD < -180)
   {
      LongitudeDD = LongitudeDD + 360.0;
   }
   else if (LongitudeDD > 180.0)
   {
      LongitudeDD = LongitudeDD - 360.0;
   }

   if ( (LongitudeDD < -180.0) || (LongitudeDD > 180.0) )
   {
      // Longitude out of range
      if(traceDebug())
      {
         ossimNotify(ossimNotifyLevel_FATAL)
            << "FATAL: " << "ossimGeoidEgm96::offsetFromEllipsoid, "
            << "Point out of range:  " << savedGpt << "\n";
      }
      return offset;
   }
   
   // Compute X and Y Offsets into Geoid Height Array:
   
   if (LongitudeDD < 0.0)
   {
      OffsetX = ( LongitudeDD + 360.0 ) * ScaleFactor;
   }
   else
   {
      OffsetX = LongitudeDD * ScaleFactor;
   }
   OffsetY = ( 90.0 - LatitudeDD ) * ScaleFactor;
   
   //---
   // Find Four Nearest Geoid Height Cells for specified Latitude,
   // Longitude;  Assumes that (0,0) of Geoid Height Array is at
   // Northwest corner:
   //---
   PostX = floor( OffsetX );
   if ((PostX + 1) == NumbGeoidCols)
      PostX--;
   PostY = floor( OffsetY );
   if ((PostY + 1) == NumbGeoidRows)
      PostY--;
   
   Index = (long)(PostY * NumbGeoidCols + PostX);
   ElevationNW = theGeoidHeightBufferPtr[ Index ];
   ElevationNE = theGeoidHeightBufferPtr[ Index+ 1 ];
   
   Index = (long)((PostY + 1) * NumbGeoidCols + PostX);
   ElevationSW = theGeoidHeightBufferPtr[ Index ];
   ElevationSE = theGeoidHeightBufferPtr[ Index + 1 ];
   
   //Perform Bi-Linear Interpolation to compute Height above Ellipsoid:
   DeltaX = OffsetX - PostX;
   DeltaY = OffsetY - PostY;
   
   UpperY = ElevationNW + DeltaX * ( ElevationNE - ElevationNW );
   LowerY = ElevationSW + DeltaX * ( ElevationSE - ElevationSW );
   
   offset = UpperY + DeltaY * ( LowerY - UpperY );
   
   return offset;
}

open()

bool ossimGeoidEgm96::open ( const ossimFilename &  grid_file, ossimByteOrder  byteOrder = OSSIM_BIG_ENDIAN  )

virtual

Implements ossimGeoid.

Definition at line 58 of file ossimGeoidEgm96.cpp.

Referenced by ossimGeoidEgm96().

{
   static const char MODULE[] = "ossimGeoidEgm96::open";

   if (traceDebug())
   {
      ossimNotify(ossimNotifyLevel_DEBUG) << MODULE << " Entered...\n";
   }

   if(theGeoidHeightBuffer.size() != NumbGeoidElevs)
   {
      theGeoidHeightBuffer.resize(NumbGeoidElevs);
      theGeoidHeightBufferPtr = &theGeoidHeightBuffer.front();
   }
   
   // int   ItemsRead = 0;
   long  ElevationsRead = 0;
   // long  ItemsDiscarded = 0;
   long  num = 0;

   ossimFilename grid = grid_file;
   if (grid_file.isDir())
   {
      grid = grid_file.dirCat("egm96.grd");
   }

   if (traceDebug())
   {
      ossimNotify(ossimNotifyLevel_DEBUG) << MODULE << " Grid file:" << grid << "\n";
   }
   
   // Open the File READONLY, or Return Error Condition:
   std::ifstream gridHeightFile(grid.c_str(), std::ios::in|std::ios::binary);
//   FILE* GeoidHeightFile;

   if ( gridHeightFile.fail())
   {
      if(traceDebug())
      {
         ossimNotify(ossimNotifyLevel_WARN) << MODULE << " could not open file "
                                            << grid.c_str() << "\n";
      }
      setErrorStatus();
      return false;
   }
  
   // Skip the Header Line:
   ossimEndian oe;
   bool swap_bytes = (ossim::byteOrder() != byteOrder) ? true : false;
   while ( (num < NumbHeaderItems)&&(!gridHeightFile.fail()))
   {      
      float f;
      gridHeightFile.read( (char*)(&f), 4);
      if (swap_bytes) oe.swap(f);
      theGeoidHeightBuffer[num] = f;
      ++num;
   }
   // Determine if header read properly, or NOT:
   if ((!ossim::almostEqual(theGeoidHeightBuffer[0], (float)-90.0)) ||
       (!ossim::almostEqual(theGeoidHeightBuffer[1], (float)90.0)) ||
       (!ossim::almostEqual(theGeoidHeightBuffer[2], (float)0.0)) ||
       (!ossim::almostEqual(theGeoidHeightBuffer[3],(float)360.0))||
       (!ossim::almostEqual(theGeoidHeightBuffer[4],(float)(1.0 / ScaleFactor ))) ||
       (!ossim::almostEqual(theGeoidHeightBuffer[5],(float)( 1.0 / ScaleFactor ))) ||
       gridHeightFile.fail())
   {
      if(traceDebug())
      {
         ossimNotify(ossimNotifyLevel_WARN) << MODULE << " bad header file "
                                            << grid.c_str() << "\n";
      }
      setErrorStatus();
      return false;
  }

   // Extract elements from the file:
   num = 0;
   while ( (num < NumbGeoidElevs)&&(!gridHeightFile.fail()) )
   {
//       if (feof( GeoidHeightFile )) break;
//       if (ferror( GeoidHeightFile )) break;
      
      float f;
      gridHeightFile.read( (char*)(&f), 4);
      if (swap_bytes) oe.swap(f);
      theGeoidHeightBuffer[num] = f;
      ++ElevationsRead;
      ++num;
   }

//    fclose(GeoidHeightFile);
   
   // Determine if all elevations of file read properly, or NOT:
   if (ElevationsRead != NumbGeoidElevs)
   {
      setErrorStatus();
      ossimSetError("ossimGeoidEgm96::open",
                    ossimErrorCodes::OSSIM_ERROR,
                    "Bad grid file...%s", grid.c_str());
     return false;
  }

   if (traceDebug())
   {
      ossimNotify(ossimNotifyLevel_DEBUG)
         << "Opened geoid grid:  " << grid.c_str() << std::endl;
   }
   
   return true;
}

Member Data Documentation

theGeoidHeightBuffer

std::vector<float> ossimGeoidEgm96::theGeoidHeightBuffer

protected

Definition at line 60 of file ossimGeoidEgm96.h.

Referenced by ossimGeoidEgm96().

theGeoidHeightBufferPtr

float* ossimGeoidEgm96::theGeoidHeightBufferPtr

mutableprotected

Definition at line 61 of file ossimGeoidEgm96.h.

Referenced by offsetFromEllipsoid().

---

The documentation for this class was generated from the following files:

• ossimGeoidEgm96.h
• ossimGeoidEgm96.cpp