Provided by: gdal-bin_3.5.1+dfsg-1build1_amd64 
NAME
gdal_calc - Command line raster calculator with numpy syntax.
SYNOPSIS
gdal_calc.py --calc=expression --outfile=out_filename [-A filename]
[--A_band=n] [-B...-Z filename] [other_options]
DESCRIPTION
Command line raster calculator with numpy syntax. Use any basic arithmetic supported by
numpy arrays such as +, -, *, and \ along with logical operators such as >. Note that all
files must have the same dimensions (unless extent option is used), but no projection
checking is performed (unless projectionCheck option is used).
--help Show this help message and exit
-h The same as --help.
--calc=expression
Calculation in numpy syntax using +, -, /, *, or any numpy array functions (i.e.
log10()). Multiple --calc options can be listed to produce a multiband file (GDAL
>= 3.2).
-A <filename>
Input gdal raster file, you can use any letter (a-z, A-Z). (lower case supported
since GDAL 3.3)
A letter may be repeated, or several values (separated by space) can be provided
(GDAL >= 3.3). Since GDAL 3.5, wildcard exceptions (using ?, *) are supported for
all shells/platforms. The effect will be to create a 3-dim numpy array. In such a
case, the calculation formula must use this input as a 3-dim array and must return
a 2D array (see examples below). In case the calculation does not return a 2D
array an error would be generated.
--A_band=<n>
Number of raster band for file A (default 1).
--outfile=<filename>
Output file to generate or fill.
--NoDataValue=<value>
Output NoDataValue (default datatype specific value). To indicate not setting a
NoDataValue use --NoDataValue=none (GDAL >= 3.3)
NOTE:
Using the Python API: None value will indicate default datatype specific value.
'none' value will indicate not setting a NoDataValue.
--hideNoData
New in version 3.3.
Ignores the input bands NoDataValue. By default, the input bands NoDataValue are
not participating in the calculation. By setting this setting - no special
treatment will be performed on the input NoDataValue. and they will be
participating in the calculation as any other value. The output will not have a
set NoDataValue, unless you explicitly specified a specific value by setting
--NoDataValue=<value>.
--type=<datatype>
Output datatype, must be one of [Int32, Int16, Float64, UInt16, Byte, UInt32,
Float32].
NOTE:
Despite the datatype set using --type, when doing intermediate aritmethic
operations using operands of the same type, the operation result will honor the
original datatype. This may lead into unexpected results in the final result.
--format=<gdal_format>
GDAL format for output file.
--color-table=<filename>
Allows specifying a filename of a color table (or a ColorTable object) (with
Palette Index interpretation) to be used for the output raster. Supported formats:
txt (i.e. like gdaldem, but color names are not supported), qlr, qml (i.e. exported
from QGIS)
--extent=<option>
New in version 3.3.
This option determines how to handle rasters with different extents. This option
is mutually exclusive with the projwin option, which is used for providing a custom
extent.
For all the options below the pixel size (resolution) and SRS (Spatial Reference
System) of all the input rasters must be the same.
ignore (default) - only the dimensions of the rasters are compared. if the
dimensions do not agree the operation will fail.
fail - the dimensions and the extent (bounds) of the rasters must agree, otherwise
the operation will fail.
union - the extent (bounds) of the output will be the minimal rectangle that
contains all the input extents.
intersect - the extent (bounds) of the output will be the maximal rectangle that is
contained in all the input extents.
--projwin <ulx> <uly> <lrx> <lry>
New in version 3.3.
This option provides a custom extent for the output, it is mutually exclusive with
the extent option.
--projectionCheck
New in version 3.3.
By default, no projection checking will be performed. By setting this option, if
the projection is not the same for all bands then the operation will fail.
--creation-option=<option>
Passes a creation option to the output format driver. Multiple options may be
listed. See format specific documentation for legal creation options for each
format.
--co=<option>
The same as creation-option.
--allBands=[a-z, A-Z]
Process all bands of given raster (a-z, A-Z). Requires a single calc for all bands.
--overwrite
Overwrite output file if it already exists. Overwriting must be understood here as
deleting and recreating the file from scratch. Note that if this option is not
specified and the output file already exists, it will be updated in place.
--debug
Print debugging information.
--quiet
Suppress progress messages.
PYTHON OPTIONS
New in version 3.3.
The following options are available by using function the python interface of gdal_calc.
They are not available using the command prompt.
user_namespace
A dictionary of custom functions or other names to be available for use in the Calc
expression.
return_ds
If enabled, the output dataset would be returned from the function and not closed.
color_table
Allows specifying a ColorTable object (with Palette Index interpretation) to be
used for the output raster.
EXAMPLE
Add two files together:
gdal_calc.py -A input1.tif -B input2.tif --outfile=result.tif --calc="A+B"
Average of two layers:
gdal_calc.py -A input1.tif -B input2.tif --outfile=result.tif --calc="(A+B)/2"
NOTE:
In the previous example, beware that if A and B inputs are of the same datatype, for
example integers, you may need to force the conversion of one of the operands before
the division operation.
gdal_calc.py -A input.tif -B input2.tif --outfile=result.tif --calc="(A.astype(numpy.float64) + B) / 2"
Add three files together (two options with the same result):
gdal_calc.py -A input1.tif -B input2.tif -C input3.tif --outfile=result.tif --calc="A+B+C"
New in version 3.3.
gdal_calc.py -A input1.tif -A input2.tif -A input3.tif --outfile=result.tif --calc="numpy.sum(A,axis=0)".
Average of three layers (two options with the same result):
gdal_calc.py -A input1.tif -B input2.tif -C input3.tif --outfile=result.tif --calc="(A+B+C)/3"
New in version 3.3.
gdal_calc.py -A input1.tif input2.tif input3.tif --outfile=result.tif --calc="numpy.average(a,axis=0)".
Maximum of three layers (two options with the same result):
gdal_calc.py -A input1.tif -B input2.tif -C input3.tif --outfile=result.tif --calc="numpy.max((A,B,C),axis=0)"
New in version 3.3.
gdal_calc.py -A input1.tif input2.tif input3.tif --outfile=result.tif --calc="numpy.max(A,axis=0)"
Set values of zero and below to null:
gdal_calc.py -A input.tif --outfile=result.tif --calc="A*(A>0)" --NoDataValue=0
Using logical operator to keep a range of values from input:
gdal_calc.py -A input.tif --outfile=result.tif --calc="A*logical_and(A>100,A<150)"
Work with multiple bands:
gdal_calc.py -A input.tif --A_band=1 -B input.tif --B_band=2 --outfile=result.tif --calc="(A+B)/2" --calc="B*logical_and(A>100,A<150)"
AUTHOR
Chris Yesson <chris dot yesson at ioz dot ac dot uk>, Etienne Tourigny <etourigny dot dev
at gmail dot com>
COPYRIGHT
1998-2022
Jun 30, 2022 GDAL_CALC(1)