The projections support (read if a *.prj file is available) is quite limited. Additional sample .prj files may be sent to the maintainer, warmerdam@pobox.com.
The NODATA value for the grid read is also preserved when available. Grids are treated as signed 16bit integer unless the first scanline contains decimal values in which case the image is treated as 32bit floating point.
The AIG GIO drivers are also available for Arc/Info Binary Grid format.
NOTE: Implemented as gdal/frmts/aaigrid/aaigriddataset.cpp.
Support includes reading of an affine georeferencing transform, some projections, and a color table (.clr) if available.
This driver is implemented based on a reverse engineering of the format. See the format description for more details.
The projections support (read if a prj.adf file is available) is quite limited. Additional sample prj.adf files may be sent to the maintainer, warmerdam@pobox.com.
Note that another driver (GIO) is available for Windows platforms with ArcView installed.
NOTE: Implemented as gdal/frmts/aigrid/aigdataset.cpp.
This driver should also support GEO/NOS format as supplied by Softchart. These files normally have the extension .nos with associated .geo files containing georeferencing ... the .geo files are currently ignored.
This driver is based on work by Mike Higgins. See the frmts/bsb/bsb_read.c files for details on patents affecting BSB format.
NOTE: Implemented as gdal/frmts/bsb/bsbdataset.cpp.
This driver is known to work with CEOS data produced by Spot Image, but will have problems with many other data sources. In particular, it will only work with eight bit unsigned data.
See the separate SAR_CEOS driver for access to SAR CEOS data products.
NOTE: Implemented as gdal/frmts/ceos/ceosdataset.cpp.
NOTE: Implemented as gdal/frmts/raw/doq1dataset.cpp.
This driver was implemented by Derrick J Brashear.
NOTE: Implemented as gdal/frmts/raw/doq2dataset.cpp.
See Also: USGS DOQ Standards
NOTE: Implemented as gdal/frmts/dted/dteddataset.cpp.
This driver may be sufficient to read GTopo 30 data, and Geospot products.
NOTE: Implemented as gdal/frmts/raw/ehdrdataset.cpp.
GDAL should support reading bil, bip and bsq interleaved formats, and most pixel types are supported, including 8, 16 and 32bit signed and unsigned integers, 32bit and 64 bit floating point, and 32bit and 64bit complex floating point. There is limited support for recognising map_info keywords with the coordinate system and georeferencing. In particular, UTM and State Plane should work.
Creation Options:
The control points of the GEOLOCATION GRID ADS dataset are read if available, generally giving a good coverage of the dataset. The GCPs are in WGS84.
Virtually all key/value pairs from the MPH and SPH (primary and secondary headers) are copied through as dataset level metadata.
NOTE: Implemented as gdal/frmts/envisat/envisatdataset.cpp.
See Also: Envisat Data Products at ESA.
FITS is a format used mainly by astronomers, but it is a relatively simple format that supports arbitrary image types and multi-spectral images, and so has found its way into GDAL. FITS support is implemented in terms of the standard CFITSIO library, which you must have on your system in order for FITS support to be enabled. Both reading and writing of FITS files is supported. At the current time, no support for a georeferencing system is implemented, but WCS (World Coordinate System) support is possible in the future.
Non-standard header keywords that are present in the FITS file will be copied to the dataset's metadata when the file is opened, for access via GDAL methods. Similarly, non-standard header keywords that the user defines in the dataset's metadata will be written to the FITS file when the GDAL handle is closed.
Note to those familiar with the CFITSIO library: The automatic rescaling of data values, triggered by the presence of the BSCALE and BZERO header keywords in a FITS file, is disabled in GDAL. Those header keywords are accessible and updatable via dataset metadata, in the same was as any other header keywords, but they do not affect reading/writing of data values from/to the file.
NOTE: Implemented as gdal/frmts/fits/fitsdataset.cpp.
This driver supports georeferencing bounds, but no projection definition. New coverages can be created with a code of GIO.
Also see the AIG read-only driver available on all platforms.
NOTE: Implemented as gdal/frmts/aigrid/giodataset.cpp.
Details on the supporting code, and format can be found on the GXF-3 page.
NOTE: Implemented as gdal/frmts/gxf/gxfdataset.cpp.
These files are represented as having one 32bit floating band with elevation data. The georeferencing of the files is returned as well as the coordinate system (always lat/long on the Tokyo datum).
There is no update or creation support for this format.
NOTE: Implemented as gdal/frmts/jdem/jdemdataset.cpp.
See Also: Geographic Survey Institute (GSI) Web Site.
Reading lat/long GCPs (TOP_LEFT_CORNER, ...) is supported but there is no support for reading affine georeferencing or projection information.
Unrecognised keywords from the .hdr file are preserved as metadata.
All data types with GDAL equivelents are supported, including 8, 16, 32 and 64 bit data precisions in integer, real and complex data types. In addition tile organized files (as produced by the Atlantis SAR Processor - APP) are supported for reading.
On creation (with a format code of MFF) a simple, ungeoreferenced raster file is created.
MFF files are not normally portable between systems with different byte orders. However GDAL honours the new BYTE_ORDER keyword which can take a value of LSB (Integer -- little endian), and MSB (Motorola -- big endian). This may be manually added to the .hdr file if required.
NOTE: Implemented as gdal/frmts/raw/mffdataset.cpp.
To select an MFF2 dataset select the directory containing the attrib, and image_data files for the dataset.
Currently only the UTM projection is supported (georef.projection.name = utm), with the affine transform computed from the lat/long control points. In any event, if GCPs are available in a georef file, they are returned with the dataset.
Newly created files (with a type of MFF2) are always just raw rasters with no georeferencing information. For read, and creation all data types (real, integer and complex in bit depths of 8, 16, 32) should be supported.
NOTE: Implemented as gdal/frmts/raw/hkvdataset.cpp.
The format type for creating new files is PAux. All PCI data types (8U, 16U, 16S, and 32R) are supported. Currently georeferencing, projections, and other metadata is ignored.
NOTE: Implemented as gdal/frmts/raw/pauxdataset.cpp.
See Also: PCI's .aux Format Description
PNG files are linearly compressed, so random reading of large PNG files can be very inefficient (resulting in many restarts of decompression from the start of the file).
Text chunks are translated into metadata, typically with multiple lines per item. World files with the extensions of .wld, .tfw or .tifw will be read. Single transparency values in greyscale files will be recognised as a nodata value in GDAL. Transparent index in paletted images are preserved when the color table is read.
PNG files can be created with a type of PNG, using the CreateCopy() method, requiring a prototype to read from. Writing includes support for the various image types, and will preserve transparency/nodata values. Georeferencing .wld files are written if option WORLFFILE setted. All pixel types other than 16bit unsigned will be written as eight bit.
Creation Options:
PNG support is implemented based on the libpng reference library. More information is available at http://www.libpng.org/pub/png.
Netpbm files can be created with a type of PNM.
Creation Options:
This driver works with most Radarsat and ERS data products, including simple look complex products; however, it is unlikely to work for non-Radar CEOS products. The simplier CEOS driver is often appropriate for these.
This driver will attempt to read 15 lat/long GCPS by sampling the per-scanline CEOS superstructure information. It also captures various pieces of metadata from various header files, including:
CEOS_LOGICAL_VOLUME_ID=EERS-1-SAR-MLD CEOS_PROCESSING_FACILITY=APP CEOS_PROCESSING_AGENCY=CCRS CEOS_PROCESSING_COUNTRY=CANADA CEOS_SOFTWARE_ID=APP 1.62 CEOS_ACQUISITION_TIME=19911029162818919 CEOS_SENSOR_CLOCK_ANGLE= 90.000 CEOS_ELLIPSOID=IUGG_75 CEOS_SEMI_MAJOR= 6378.1400000 CEOS_SEMI_MINOR= 6356.7550000NOTE: Implemented as gdal/frmts/ceos2/sar_ceosdataset.cpp.
SDTS datasets consist of a number of files. Each DEM should have one file with a name like XXXCATD.DDF. This should be selected to open the dataset.
The elevation units of DEMs may be feet or meters. The GetType() method on a band will attempt to return if the units are Feet ("ft") or Meters ("m"). NOTE: Implemented as gdal/frmts/sdts/sdtsdataset.cpp.
The 7.5 minute (UTM grid) USGS DEM files will generally have regions of missing data around the edges, and these are properly marked with a nodata value. Elevation values in USGS DEM files may be in meters or feet, and this will be indicated by the return value of GDALRasterBand::GetUnitType() (either "m" or "ft").
Note that USGS DEM files are represented as one big tile. This may cause cache thrashing problems if the GDAL tile cache size is small. It will also result in a substantial delay when the first pixel is read as the whole file will be ingested.
Some of the code for implementing usgsdemdataset.cpp was derived from VTP code by Ben Discoe. See the Virtual Terrain project for more information on VTP.
NOTE: Implemented as gdal/frmts/sdts/usgsdemdataset.cpp.
The XPM support does not support georeferecing (not available from XPM files) nor does it support XPM files with more than one character per pixel. New XPM files must be colormapped or greyscale, and colortables will be reduced to about 70 colors automatically.
NOTE: Implemented as gdal/frmts/xpm/xpmdataset.cpp.