GDAL_FOOTPRINT(1) GDAL GDAL_FOOTPRINT(1)

NAME

gdal_footprint - Compute footprint of a raster.

SYNOPSIS

gdal_footprint [--help] [--help-general]
[-b <band>]... [-combine_bands union|intersection]
[-oo <NAME>=<VALUE>]... [-ovr <index>]
[-srcnodata "<value>[ <value>]..."]
[-t_cs pixel|georef] [-t_srs <srs_def>] [-split_polys]
[-convex_hull] [-densify <value>] [-simplify <value>]
[-min_ring_area <value>] [-max_points <value>|unlimited]
[-of <ogr_format>] [-lyr_name <dst_layername>]
[-location_field_name <field_name>] [-no_location]
[-write_absolute_path]
[-dsco <name>=<value>]... [-lco <name>=<value>]... [-overwrite] [-q]
<src_filename> <dst_filename>

DESCRIPTION

The gdal_footprint utility can be used to compute the footprint of a
raster file, taking into account nodata values (or more generally the
mask band attached to the raster bands), and generating
polygons/multipolygons corresponding to areas where pixels are valid,
and write to an output vector file.

The nearblack utility may be run as a pre-processing step to generate
proper mask bands.

--help Show this help message and exit

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

-b <band>
Band(s) of interest. Between 1 and the number of bands of the
raster. May be specified multiple times. If not specified,
all bands are taken into account. The way multiple bands are
combined is controlled by -combine_bands

-combine_bands union|intersection
Defines how the mask bands of the selected bands are combined
to generate a single mask band, before being vectorized. The
default value is union: that is a pixel is valid if it is
valid at least for one of the selected bands. intersection
means that a pixel is valid only ifit is valid for all
selected bands.

-ovr <index>
To specify which overview level of source file must be used,
when overviews are available on the source raster. By default
the full resolution level is used. The index is 0-based, that
is 0 means the first overview level. This option is mutually
exclusive with -srcnodata.

-srcnodata "<value>[ <value>]..."
Set nodata values for input bands (different values can be
supplied for each band). If a single value is specified, it
applies to all selected bands. If more than one value is
supplied, there should be as many values as the number of
selected bands, and all values should be quoted to keep them
together as a single operating system argument. If the option
is not specified, the intrinsic mask band of each selected
bands will be used.

-t_cs pixel|georef
Target coordinate system. By default if the input dataset is
georeferenced, georef is implied, that is the footprint
geometry will be expressed as coordinates in the CRS of the
raster (or the one specified with -t_srs). If specifying
pixel, the coordinates of the footprint geometry are column
and line indices.

-t_srs <srs_def>
Target CRS of the output file. The <srs_def> may be any of
the usual GDAL/OGR forms, complete WKT, PROJ.4, EPSG:n or a
file containing the WKT. Specifying this option implies -t_cs
georef The footprint is reprojected from the CRS of the source
raster to the specified CRS.

-split_polys
When specified, multipolygons are split as several features
each with one single polygon.

-convex_hull
When specified, the convex hull of (multi)polygons is
computed.

-densify <value>
The specified value of this option is the maximum distance
between 2 consecutive points of the output geometry. The unit
of the distance is in pixels if -t_cs equals pixel, or
otherwise in georeferenced units of the source raster. This
option is applied before the reprojection implied by -t_srs.

-simplify <value>
The specified value of this option is the tolerance used to
merge consecutive points of the output geometry using the
OGRGeometry::Simplify() method. The unit of the distance is
in pixels if -t_cs equals pixel, or otherwise in georeferenced
units of the target vector dataset. This option is applied
after the reprojection implied by -t_srs.

-min_ring_area <value>
Minimum value for the area of a ring The unit of the area is
in square pixels if -t_cs equals pixel, or otherwise in
georeferenced units of the target vector dataset. This option
is applied after the reprojection implied by -t_srs

-max_points <value>|unlimited
Maximum number of points of each output geometry (not counting
the closing point of each ring, which is always identical to
the first point). The default value is 100. unlimited can be
used to remove that limitation.

-q Suppress progress monitor and other non-error output.

-oo <NAME>=<VALUE>
Dataset open option (format specific)

-of <ogr_format>
Select the output format. Use the short format name. Guessed
from the file extension if not specified

-location_field_name <field_name>
New in version 3.9.0.


Specifies the name of the field in the resulting vector
dataset where the path of the input dataset will be stored.
The default field name is "location". To prevent writing the
path of the input dataset, use -no_location

-no_location
New in version 3.9.0.


Turns off the writing of the path of the input dataset as a
field in the output vector dataset.

-write_absolute_path
New in version 3.9.0.


Enables writing the absolute path of the input dataset. By
default, the filename is written in the location field exactly
as specified on the command line.

-lco <NAME>=<VALUE>
Layer creation option (format specific)

-dsco <NAME>=<VALUE>
Dataset creation option (format specific)

-lyr_name <value>
Name of the target layer. footprint if not specified.

-overwrite
Overwrite the target layer if it exists.

<src_filename>
The source raster file name.

<dst_filename>
The destination vector file name. If the file and the output
layer exist, the new footprint is appended to them, unless
-overwrite is used.

Post-vectorization geometric operations are applied in the following
order:

+o optional splitting (-split_polys)

+o optional densification (-densify)

+o optional reprojection (-t_srs)

+o optional filtering by minimum ring area (-min_ring_area)

+o optional application of convex hull (-convex_hull)

+o optional simplification (-simplify)

+o limitation of number of points (-max_points)

C API

This utility is also callable from C with GDALFootprint().

EXAMPLES

+o Compute the footprint of a GeoTIFF file as a GeoJSON file using WGS
84 longitude, latitude coordinates

gdal_footprint -t_srs EPSG:4326 input.tif output.geojson

AUTHOR

Even Rouault <even.rouault@spatialys.com>

COPYRIGHT

1998-2025

January 8, 2025 GDAL_FOOTPRINT(1)