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>]
             [-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 interested. 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

       -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:

       • optional splitting (-split_polys)

       • optional densification (-densify)

       • optional reprojection (-t_srs)

       • optional filtering by minimum ring area (-min_ring_area)

       • optional application of convex hull (-convex_hull)

       • optional simplification (-simplify)

       • limitation of number of points (-max_points)

C API

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

EXAMPLES

       • 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

       1998-2024

                                           Feb 08, 2024                         GDAL_FOOTPRINT(1)