NAME

gdalcompare - Compare two images.

SYNOPSIS

gdalcompare [--help] [--help-general]


               [-dumpdiffs] [-skip_binary] [-skip_overviews]


               [-skip_geolocation] [-skip_geotransform]


               [-skip_metadata] [-skip_rpc] [-skip_srs]


               [-sds] <golden_file> <new_file>

DESCRIPTION

gdalcompare compares two GDAL supported datasets and reports the differences. In addition to reporting differences to the standard output the script will also return the difference count in its exit value.

Image pixels, and various metadata are checked. There is also a byte by byte comparison done which will count as one difference. So if it is only important that the GDAL visible data is identical a difference count of 1 (the binary difference) should be considered acceptable.

NOTE:

gdalcompare is a Python utility, and is only available if GDAL Python bindings are available.

--help: Show this help message and exit

--help-general: Gives a brief usage message for the generic GDAL commandline options and exit.

-dumpdiffs

Added in version 3.8.

Whether to output the difference in pixel content in a TIFF file in the current directory.

-skip_binary

Added in version 3.8.

Whether to skip exact comparison of binary content.

-skip_overviews

Added in version 3.8.

Whether to skip comparison of overviews.

-skip_geolocation

Added in version 3.8.

Whether to skip comparison of GEOLOCATION metadata domain.

-skip_geotransform

Added in version 3.8.

Whether to skip comparison of geotransform matrix.

-skip_metadata

Added in version 3.8.

Whether to skip comparison of metadata

-skip_rpc

Added in version 3.8.

Whether to skip comparison of Rational Polynomial Coefficients (RPC) metadata domain.

-skip_srs

Added in version 3.8.

Whether to skip comparison of spatial reference systems (SRS).

-sds: If this flag is passed the script will compare all subdatasets that are part of the dataset, otherwise subdatasets are ignored.

<golden_file>: The file that is considered correct, referred to as the golden file.

<new_file>: The file being compared to the golden file, referred to as the new file.

Note that the gdalcompare script (like all the other scripts) can also be called as a library from python code: from osgeo_utils import gdalcompare. The primary entry point is gdalcompare.compare_db() which takes a golden gdal.Dataset and a new gdal.Dataset as arguments and returns a difference count (excluding the binary comparison). The gdalcompare.compare_sds() entry point can be used to compare subdatasets.

EXAMPLES

gdalcompare -dumpdiffs N.tiff S.tiff; echo $?
Files differ at the binary level.
Band 1 checksum difference:


  Golden: 36694


  New:    40645


  Pixels Differing: 1509


  Maximum Pixel Difference: 255.0


  Wrote Diffs to: 1.tif
Differences Found: 2
2
gdalcompare N.tiff N.tiff; echo $?
Differences Found: 0
0

AUTHOR

Frank Warmerdam <warmerdam@pobox.com>

COPYRIGHT

1998-2025