`gdal raster scale`

Added in version 3.11.

Scale the values of the bands of a raster dataset

Synopsis

Usage: gdal raster scale [OPTIONS] <INPUT> <OUTPUT>

Scale the values of the bands of a raster dataset.

Positional arguments:
  -i, --input <INPUT>                                      Input raster dataset [required]
  -o, --output <OUTPUT>                                    Output raster dataset [required]

Common Options:
  -h, --help                                               Display help message and exit
  --json-usage                                             Display usage as JSON document and exit
  --config <KEY>=<VALUE>                                   Configuration option [may be repeated]
  --progress                                               Display progress bar

Options:
  -f, --of, --format, --output-format <OUTPUT-FORMAT>      Output format ("GDALG" allowed)
  --co, --creation-option <KEY>=<VALUE>                    Creation option [may be repeated]
  --overwrite                                              Whether overwriting existing output is allowed
  --ot, --datatype, --output-data-type <OUTPUT-DATA-TYPE>  Output data type. OUTPUT-DATA-TYPE=Byte|Int8|UInt16|Int16|UInt32|Int32|UInt64|Int64|CInt16|CInt32|Float16|Float32|Float64|CFloat32|CFloat64
  -b, --band <BAND>                                        Select band to restrict the scaling (1-based index)
  --src-min <SRC-MIN>                                      Minimum value of the source range
  --src-max <SRC-MAX>                                      Maximum value of the source range
  --dst-min <DST-MIN>                                      Minimum value of the destination range
  --dst-max <DST-MAX>                                      Maximum value of the destination range
  --exponent <EXPONENT>                                    Exponent to apply non-linear scaling with a power function
  --no-clip                                                Do not clip input values to [srcmin, srcmax]

Advanced Options:
  --if, --input-format <INPUT-FORMAT>                      Input formats [may be repeated]
  --oo, --open-option <KEY>=<VALUE>                        Open options [may be repeated]

Description

gdal raster scale can be used to rescale the input pixels values from the range --src-min to --src-max to the range --dst-min to --dst-max. It is also often necessary to reset the output datatype with the --ot switch. If omitted the output range is from the minimum value to the maximum value allowed for integer data types (for example from 0 to 255 for Byte output) or from 0 to 1 for floating-point data types. If omitted the input range is automatically computed from the source dataset. 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 gdal raster edit --stats {source_dataset} priorly to precompute statistics, for formats that support serializing statistics computations (GeoTIFF, VRT...) Source values are clipped to the range defined by srcmin and srcmax, unless --no-clip is set.

By default, the scaling is applied to all bands. It is possible to restrict it to a single band with --band and leave values of other bands unmodified.

This command is the reverse operation of gdal raster unscale.

This subcommand is also available as a potential step of gdal raster pipeline

Standard options

-f, --of, --format, --output-format <OUTPUT-FORMAT>: Which output raster format to use. Allowed values may be given by gdal --formats | grep raster | grep rw | sort

--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.

May be repeated.

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.

--overwrite: Allow program to overwrite existing target file or dataset. Otherwise, by default, gdal errors out if the target file or dataset already exists.

--ot, --datatype, --output-data-type <OUTPUT-DATA-TYPE>: Output data type among Byte, Int8, UInt16, Int16, UInt32, Int32, UInt64, Int64, CInt16, CInt32, Float32, Float64, CFloat32, CFloat64.

-b, --band <BAND>: Index (starting at 1) of the band to which the scaling must be only applied.

--src-min <SRCMIN>: Minimum value of the source range. If not specified, it will be calculated from the input dataset. This option must be used together with --src-max.

--src-max <SRCMAX>: Maximum value of the source range. If not specified, it will be calculated from the source dataset. This option must be used together with --src-min.

--dst-min <DSTMIN>: Minimum value of the output range. This option must be used together with --dst-max.

--dst-max <DSTMAX>: Maximum value of the output range. This option must be used together with --dst-min.

--exponent <EXPONENT>

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 --src-min / --src-max / --dst-min / --dst-max options.

The scaled value Dst is calculated from the source value Src with the following formula:

\[{Dst} = \left( {Dst}_{max} - {Dst}_{min} \right) \times \operatorname{max} \left( 0, \operatorname{min} \left( 1, \left( \frac{{Src} - {Src}_{min}}{{Src}_{max}-{Src}_{min}} \right)^{exp\_val} \right) \right) + {Dst}_{min}\]

Note

gdal raster unscale assumes linear scaling, and this cannot unscale values back to the original ones.

--no-clip: Disable clipping input values to the source range. Note that using this option with non-linear scaling with a non-integer exponent will cause input values lower than the minimum value of the source range to be mapped to not-a-number.

GDALG output (on-the-fly / streamed dataset)

This program supports serializing the command line as a JSON file using the GDALG output format. The resulting file can then be opened as a raster dataset using the GDALG: GDAL Streamed Algorithm driver, and apply the specified pipeline in a on-the-fly / streamed way.

Examples

Example 1: Rescale linearly values of a UInt16 dataset from [0,4095] to a Byte dataset [0,255]

$ gdal raster scale --datatype Byte --src-min 0 --src-max 4095 uint16.tif byte.tif --overwrite

gdal raster scale