Man Linux: Main Page and Category List


       gdal_utilities - GDAL Utilities The following utility programs are
       distributed with GDAL.

       · gdalinfo - report information about a file.
       · gdal_translate - Copy a raster file, with control of output format.
       · gdaladdo - Add overviews to a file.
       · gdalwarp - Warp an image into a new coordinate system.
       · gdaltindex - Build a MapServer raster tileindex.
       · gdalbuildvrt - Build a VRT from a list of datasets.
       · gdal_contour - Contours from DEM.
       · - Convert a 24bit RGB image to 8bit paletted.
       · - Convert an 8bit paletted image to 24bit RGB.
       · - Build a quick mosaic from a set of images.
       · - Create a TMS tile structure, KML and simple web
       · gdal_rasterize - Rasterize vectors into raster file.
       · gdaltransform - Transform coordinates.
       · nearblack - Convert nearly black/white borders to exact value.
       · - Retiles a set of tiles and/or build tiled pyramid
       · gdal_grid - Create raster from the scattered data.
       · gdal_proximity - Compute a raster proximity map.
       · gdal_polygonize - Generate polygons from raster.
       · gdal_sieve - Raster Sieve filter.
       · gdal-config - Get options required to build software using GDAL.

Creating New Files

       Access an existing file to read it is generally quite simple. Just
       indicate the name of the file or dataset on the commandline. However,
       creating a file is more complicated. It may be necessary to indicate
       the the format to create, various creation options affecting how it
       will be created and perhaps a coordinate system to be assigned. Many of
       these options are handled similarly by different GDAL utilities, and
       are introduced here.
       -of format
           Select the format to create the new file as. The formats are
           assigned short names such as GTiff (for GeoTIFF) or HFA (for Erdas
           Imagine). The list of all format codes can be listed with the
           --formats switch. Only formats list as ’(rw)’ (read-write) can be
       Many utilities default to creating GeoTIFF files if a format is not
       specified. File extensions are not used to guess output format, nor are
       extensions generally added by GDAL if not indicated in the filename by
       the user.
       -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.
       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 ’--format <format>’ commandline
       option but the web page for the format is the definitive source of
       information on driver creation options.
       -a_srs SRS
           Several utilities, (gdal_translate and gdalwarp) include the
           ability to specify coordinate systems with commandline options like
           -a_srs (assign SRS to output), -s_srs (source SRS) and -t_srs
           (target SRS).
       These utilities allow the coordinate system (SRS = spatial reference
       system) to be assigned in a variety of formats.
       · NAD27/NAD83/WGS84/WGS72: These common geographic (lat/long)
         coordinate systems can be used directly by these names.

       · EPSG:n: Coordinate systems (projected or geographic) can be selected
         based on their EPSG codes, for instance EPSG:27700 is the British
         National Grid. A list of EPSG coordinate systems can be found in the
         GDAL data files gcs.csv and pcs.csv.

       · PROJ.4 Definitions: A PROJ.4 definition string can be used as a
         coordinate system. For instance ’+proj=utm +zone=11 +datum=WGS84’.
         Take care to keep the proj.4 string together as a single argument to
         the command (usually by double quoting).

       · OpenGIS Well Known Text: The Open GIS Consortium has defined a
         textual format for describing coordinate systems as part of the
         Simple Features specifications. This format is the internal working
         format for coordinate systems used in GDAL. The name of a file
         containing a WKT coordinate system definition may be used a
         coordinate system argument, or the entire coordinate system itself
         may be used as a commandline option (though escaping all the quotes
         in WKT is quite challenging).

       · ESRI Well Known Text: ESRI uses a slight variation on OGC WKT format
         in their ArcGIS product (ArcGIS .prj files), and these may be used in
         a similar manner to WKT files, but the filename should be prefixed
         with ESRI::. For example ’ESRI::NAD 1927 StatePlane Wyoming West FIPS

       · Spatial References from URLs: For example
         equal-area/. See this blog entry for more reference.

General Command Line Switches

       All GDAL command line utility programs support the following ’general’
           Report the version of GDAL and exit.
           List all raster formats supported by this GDAL build (read-only and
           read-write) and exit. The format support is indicated as follows:
           ’ro’ is read-only driver; ’rw’ is read or write (ie. supports
           CreateCopy); ’rw+’ is read, write and update (ie. supports Create).
       --format format
           List detailed information about a single format driver. The format
           should be the short name reported in the --formats list, such as
       --optfile file
           Read the named file and substitute the contents into the
           commandline options list. Lines beginning with # will be ignored.
           Multi-word arguments may be kept together with double quotes.
       --config key value
           Sets the named configuration keyword to the given value, as opposed
           to setting them as environment variables. Some common configuration
           keywords are GDAL_CACHEMAX (memory used internally for caching in
           megabytes) and GDAL_DATA (path of the GDAL ’data’ directory).
           Individual drivers may be influenced by other configuration
       --debug value
           Control what debugging messages are emitted. A value of ON will
           enable all debug messages. A value of OFF will disable all debug
           messages. Another value will select only debug messages containing
           that string in the debug prefix code.
           Gives a brief usage message for the generic GDAL commandline
           options and exit.