gdal_utilitiesGDAL Utilities
- A collection of GDAL related programs.
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.
- gdaldem - Tools to analyze and visualize DEMs.
- rgb2pct - Convert a 24bit RGB image to 8bit paletted.
- pct2rgb - Convert an 8bit paletted image to 24bit RGB.
- gdal_merge - Build a quick mosaic from a set of images.
- gdal2tiles - Create a TMS tile structure, KML and simple web
viewer.
- gdal_rasterize - Rasterize vectors into raster file.
- gdaltransform - Transform coordinates.
- nearblack - Convert nearly black/white borders to exact value.
- gdal_retile - Retiles a set of tiles and/or build tiled pyramid
levels.
- 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_fillnodata - Interpolate in nodata regions.
- gdallocationinfo - Query raster at a location.
- gdalsrsinfo - Report a given SRS in different formats. (GDAL >=
1.9.0)
- gdalmove - Transform the coordinate system of a file (GDAL >=
1.10)
- gdal_edit - Edit in place various information of an existing GDAL
dataset (projection, geotransform, nodata, metadata)
- gdal_calc - Command line raster calculator with numpy syntax
- gdal_pansharpen - Perform a pansharpen operation.
- gdal-config - Get options required to build software using
GDAL.
- gdalmanage - Identify, copy, rename and delete raster.
- gdalcompare - Compare two images and report on differences.
Access an existing file to read it is generally quite simple. Just
indicate the name of the file or dataset on the command line. 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 written.
Starting with GDAL 2.3, if not specified, the format is guessed
from the extension (previously was generally GTiff for raster, or ESRI
Shapefile for vector).
- -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>' command line
option but the web page for the format is the definitive source of
information on driver creation options. See format specific documentation
for legal creation options for each format
- -a_srs
SRS
- Several utilities, (gdal_translate and gdalwarp) include the ability to
specify coordinate systems with command line 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 command line 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
4904.prj'.
- Spatial References from URLs: For example
http://spatialreference.org/ref/user/north-pacific-albers-conic-equal-area/.
- filename: The name of a file containing WKT, PROJ.4 strings, or
XML/GML coordinate system definitions can be provided.
All GDAL command line utility programs support the following
'general' options.
- --version
- Report the version of GDAL and exit.
- --formats
- 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 (i.e. supports CreateCopy); 'rw+'
is read, write and update (i.e. supports Create). A 'v' is appended for
formats supporting virtual IO (/vsimem, /vsigzip, /vsizip, etc). A 's' is
appended for formats supporting subdatasets. Note: The valid formats for
the output of gdalwarp are formats that support the Create() method
(marked as rw+), not just the CreateCopy() method.
- --format
format
- List detailed information about a single format driver. The format
should be the short name reported in the --formats list, such as
GTiff.
- --optfile
file
- Read the named file and substitute the contents into the command line
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 options.
- --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.
- --help-general
- Gives a brief usage message for the generic GDAL command line options and
exit.