# gdal_translate

Converts raster data between different formats.

## Synopsis

    gdal_translate [--help-general]
        [-ot {Byte/Int8/Int16/UInt16/UInt32/Int32/UInt64/Int64/Float32/Float64/
                CInt16/CInt32/CFloat32/CFloat64}] [-strict]
        [-if format]* [-of format]
        [-b band]* [-mask band] [-expand {gray|rgb|rgba}]
        [-outsize xsize[%]|0 ysize[%]|0] [-tr xres yres]
        [-ovr level|AUTO|AUTO-n|NONE]
        [-r {nearest,bilinear,cubic,cubicspline,lanczos,average,rms,mode}]
        [-unscale] [-scale[_bn] [src_min src_max [dst_min dst_max]]]* [-exponent[_bn] exp_val]*
        [-srcwin xoff yoff xsize ysize] [-epo] [-eco]
        [-projwin ulx uly lrx lry] [-projwin_srs srs_def]
        [-a_srs srs_def] [-a_coord_epoch <epoch>]
        [-a_ullr ulx uly lrx lry] [-a_nodata value]
        [-a_scale value] [-a_offset value]
        [-nogcp] [-gcp pixel line easting northing [elevation]]*
        |-colorinterp{_bn} {red|green|blue|alpha|gray|undefined}]
        |-colorinterp {red|green|blue|alpha|gray|undefined},...]
        [-mo "META-TAG=VALUE"]* [-q] [-sds]
        [-co "NAME=VALUE"]* [-stats] [-norat] [-noxmp]
        [-oo NAME=VALUE]*
        src_dataset dst_dataset

## Description

The gdal_translate utility can be used to convert raster data between different formats, potentially performing some operations like subsettings, resampling, and rescaling pixels in the process.

-ot <type>

  Force the output image bands to have a specific data type supported by the driver, which may be one of the following: `Byte`, `Int8`, `UInt16`, `Int16`, `UInt32`, `Int32`, `UInt64`, `Int64`, `Float32`, `Float64`, `CInt16`, `CInt32`, `CFloat32` or `CFloat64`.

-strict

  Don’t be forgiving of mismatches and lost data when translating to the output format.

-if <format>

  Format/driver name to be attempted to open the input file(s). It is generally not necessary to specify it, but it can be used to skip automatic driver detection, when it fails to select the appropriate driver. This option can be repeated several times to specify several candidate drivers.

  New in version 3.2.

-of <format>

  Select the output format. Starting with GDAL 2.3, if not specified, the format is guessed from the extension (previously was GTiff). Use the short format name.

-b <band>

  Select an input band band for output. Bands are numbered from 1. Multiple `-b` switches may be used to select a set of input bands to write to the output file, or to reorder bands. band can also be set to “mask,1” (or just “mask”) to mean the mask band of the first band of the input dataset.

-mask <band>

  Select an input band band to create output dataset mask band. Bands are numbered from 1. band can be set to “none” to avoid copying the global mask of the input dataset if it exists. Otherwise it is copied by default (“auto”), unless the mask is an alpha channel, or if it is explicitly used to be a regular band of the output dataset (“-b mask”). band can also be set to “mask,1” (or just “mask”) to mean the mask band of the 1st band of the input dataset.

-expand gray|rgb|rgba

  To expose a dataset with 1 band with a color table as a dataset with 3 (RGB) or 4 (RGBA) bands. Useful for output drivers such as JPEG, JPEG2000, MrSID, ECW that don’t support color indexed datasets. The ‘gray’ value enables to expand a dataset with a color table that only contains gray levels to a gray indexed dataset.

-outsize <xsize>[%]|0 <ysize>[%]|0

  Set the size of the output file. Outsize is in pixels and lines unless ‘%’ is attached in which case it is as a fraction of the input image size. If one of the 2 values is set to 0, its value will be determined from the other one, while maintaining the aspect ratio of the source dataset.

-tr <xres> <yres>

  set target resolution. The values must be expressed in georeferenced units. Both must be positive values. This is mutually exclusive with `-outsize` and `-a_ullr`.

-ovr <level|AUTO|AUTO-n|NONE>

  New in version 3.6.

  To specify which overview level of source file must be used. The default choice, AUTO, will select the overview level whose resolution is the closest to the target resolution. Specify an integer value (0-based, i.e. 0=1st overview level) to select a particular level. Specify AUTO-n where n is an integer greater or equal to 1, to select an overview level below the AUTO one. Or specify NONE to force the base resolution to be used (can be useful if overviews have been generated with a low quality resampling method, and a higher quality resampling method is specified with `-r`.

  When `-ovr` is specified to an integer value, and none of `-outsize` and `-tr` is specified, the size of the overview will be used as the output size.

  When `-ovr` is specified, values of `-srcwin`, when specified, should be expressed as pixel offset and size of the full resolution source dataset. Similarly when using `-outsize` with percentage values, they refer to the size of the full resolution source dataset.

-r {nearest (default),bilinear,cubic,cubicspline,lanczos,average,rms,mode}

  Select a resampling algorithm.

  `nearest` applies a nearest neighbour (simple sampling) resampler

  `average` computes the average of all non-NODATA contributing pixels. Starting with GDAL 3.1, this is a weighted average taking into account properly the weight of source pixels not contributing fully to the target pixel.

  `rms` computes the root mean squared / quadratic mean of all non-NODATA contributing pixels (GDAL >= 3.3)

  `bilinear` applies a bilinear convolution kernel.

  `cubic` applies a cubic convolution kernel.

  `cubicspline` applies a B-Spline convolution kernel.

  `lanczos` applies a Lanczos windowed sinc convolution kernel.

  `mode` selects the value which appears most often of all the sampled points.

-scale [src_min src_max [dst_min dst_max]]

  Rescale the input pixels values from the range src_min to src_max to the range dst_min to dst_max. If omitted the output range is 0 to 255. If omitted the input range is automatically computed from the source dataset, in its whole (not just the window of interest potentially specified with `-srcwin` or `-projwin`). This may be a slow operation on a large source dataset, and if using it multiple times for several gdal_translate invocation, it might be beneficial to call `gdalinfo -stats {source_dataset}` priorly to precompute statistics, for formats that support serializing statistics computations (GeoTIFF, VRT…) Note that the values specified after `-scale` are only used to compute a scale and offset to apply to the input raster values. In particular, `src_min` and `src_max` are not used to clip input values. `-scale` can be repeated several times (if specified only once, it also applies to all bands of the output dataset), so as to specify per band parameters. It is also possible to use the “-scale_bn” syntax where bn is a band number (e.g. “-scale_2” for the 2nd band of the output dataset) to specify the parameters of one or several specific bands.

-exponent <exp_val>

  To apply non-linear scaling with a power function. exp_val is the exponent of the power function (must be positive). This option must be used with the -scale option. If specified only once, -exponent applies to all bands of the output image. It can be repeated several times so as to specify per band parameters. It is also possible to use the “-exponent_bn” syntax where bn is a band number (e.g. “-exponent_2” for the 2nd band of the output dataset) to specify the parameters of one or several specific bands.

-unscale

  Apply the scale/offset metadata for the bands to convert scaled values to unscaled values. It is also often necessary to reset the output datatype with the `-ot` switch. The unscaled value is computed from the scaled raw value with the following formula:

  \[{unscaled\_value} = {scaled\_value} * {scale} + {offset}\]

-srcwin <xoff> <yoff> <xsize> <ysize>

  Selects a subwindow from the source image for copying based on pixel/line location.

-projwin <ulx> <uly> <lrx> <lry>

  Selects a subwindow from the source image for copying (like `-srcwin`) but with the corners given in georeferenced coordinates (by default expressed in the SRS of the dataset. Can be changed with `-projwin_srs`).

  Note

  In GDAL 2.1.0 and 2.1.1, using -projwin with coordinates not aligned with pixels will result in a sub-pixel shift. This has been corrected in later versions. When selecting non-nearest neighbour resampling, starting with GDAL 2.1.0, sub-pixel accuracy is however used to get better results.

-projwin_srs <srs_def>

  Specifies the SRS in which to interpret the coordinates given with `-projwin`. The <srs_def> may be any of the usual GDAL/OGR forms, complete WKT, PROJ.4, EPSG:n or a file containing the WKT.

  Warning

  This does not cause reprojection of the dataset to the specified SRS.

-epo

  (Error when Partially Outside) If this option is set, `-srcwin` or `-projwin` values that falls partially outside the source raster extent will be considered as an error. The default behavior is to accept such requests, when they were considered as an error before.

-eco

  (Error when Completely Outside) Same as `-epo`, except that the criterion for erroring out is when the request falls completely outside the source raster extent.

-a_srs <srs_def>

  Override the projection for the output file.

  The coordinate reference systems that can be passed are anything supported by the OGRSpatialReference.SetFromUserInput() call, which includes EPSG Projected, Geographic or Compound CRS (i.e. EPSG:4296), a well known text (WKT) CRS definition, PROJ.4 declarations, or the name of a .prj file containing a WKT CRS definition.

  Note

  No reprojection is done.

-a_coord_epoch <epoch>

  New in version 3.4.

  Assign a coordinate epoch, linked with the output SRS. Useful when the output SRS is a dynamic CRS.

-a_scale <value>

  Set band scaling value (no modification of pixel values is done)

  New in version 2.3.

-a_offset<value>

  Set band offset value (no modification of pixel values is done)

  New in version 2.3.

-a_ullr <ulx> <uly> <lrx> <lry>

  Assign/override the georeferenced bounds of the output file. This assigns georeferenced bounds to the output file, ignoring what would have been derived from the source file. So this does not cause reprojection to the specified SRS.

-a_nodata <value>

  Assign a specified nodata value to output bands. It can be set to `none` to avoid setting a nodata value to the output file if one exists for the source file. Note that, if the input dataset has a nodata value, this does not cause pixel values that are equal to that nodata value to be changed to the value specified with this option.

-colorinterp_X <red|green|blue|alpha|gray|undefined>

  Override the color interpretation of band X (where X is a valid band number, starting at 1)

  New in version 2.3.

-colorinterp <red|green|blue|alpha|gray|undefined[,red|green|blue|alpha|gray|undefined]*>

  Override the color interpretation of all specified bands. For example -colorinterp red,green,blue,alpha for a 4 band output dataset.

  New in version 2.3.

-mo META-TAG=VALUE

  Passes a metadata key and value to set on the output dataset if possible.

-co <NAME=VALUE>

  Many formats have one or more optional creation options that can be used to control particulars about the file created. For instance, the GeoTIFF driver supports creation options to control compression, and whether the file should be tiled.

  The creation options available vary by format driver, and some simple formats have no creation options at all. A list of options supported for a format can be listed with the –formats command line option but the documentation for the format is the definitive source of information on driver creation options. See Raster drivers format specific documentation for legal creation options for each format.

-nogcp

  Do not copy the GCPs in the source dataset to the output dataset.

-gcp <pixel> <line> <easting> <northing> <elevation>

  Add the indicated ground control point to the output dataset. This option may be provided multiple times to provide a set of GCPs.

-q

  Suppress progress monitor and other non-error output.

-sds

  Copy all subdatasets of this file to individual output files. Use with formats like HDF that have subdatasets.

-stats

  Force (re)computation of statistics.

-norat

  Do not copy source RAT into destination dataset.

-noxmp

  Do not copy the XMP metadata in the source dataset to the output dataset when driver is able to copy it.

  New in version 3.2.

-oo NAME=VALUE

  Dataset open option (format specific)

<src_dataset>

  The source dataset name. It can be either file name, URL of data source or subdataset name for multi-dataset files.

<dst_dataset>

  The destination file name.

## Nodata / source validity mask handling during resampling

Masked values, either identified through a nodata value metadata set on the source band, a mask band, an alpha band will not be used during resampling (when using `-outsize` or `-tr`).

The details of how it is taken into account depends on the resampling kernel:

- for nearest resampling, for each target pixel, one of the potential contributing source pixels is selected (in an implementation specific way). Its value is used as it, be it valid or invalid.

- for bilinear, cubic, cubicspline and lanczos, for each target pixel, the weights of contributing source pixels is set to zero to ignore them when they are masked. There is an extra specificity for cubic: given that some of the weights in the kernel are negative, such strategy could lead to strong overshoot/undershoot when there is an alternance of valid and invalid pixels. Consequently, if any of the horizontal or vertical direction, if the maximum number of valid source pixels in each dimension is less than the radius of the resampling kernel, the target pixel is considered as nodata.

- for the other resampling methods, source pixels contributing to the target pixel are ignored if masked. Only the valid ones are taken into account. If there are none, the target pixel is considered as nodata.

## C API

This utility is also callable from C with `GDALTranslate()`.

New in version 2.1.

## Examples

    gdal_translate -of GTiff -co "TILED=YES" utm.tif utm_tiled.tif

To create a JPEG-compressed TIFF with internal mask from a RGBA dataset

    gdal_translate rgba.tif withmask.tif -b 1 -b 2 -b 3 -mask 4 -co COMPRESS=JPEG -co PHOTOMETRIC=YCBCR --config GDAL_TIFF_INTERNAL_MASK YES

To create a RGBA dataset from a RGB dataset with a mask

    gdal_translate withmask.tif rgba.tif -b 1 -b 2 -b 3 -b mask