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r.out.gdalallows a user to export a GRASS raster map layer
into any GDAL supported raster map format.

For possible metaopt parameters see the 'supported formats' pages
of GDAL.
The createopt may be used to create TFW or World files ("TFW=YES",
"WORLDFILE=ON").

r.out.gdal also supports the export of multiband rasters through
a group (created e.g. with i.group), when the group's name is entered
as input.

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The set of "http://www.gdal.org/formats_list.html (supported
raster formats) written by <EM>r.out.gdal depends on the
local GDAL installation. Available may be (incomplete list):

  AAIGrid: Arc/Info ASCII Grid
  BMP: MS Windows Device Independent Bitmap
  BSB: Maptech BSB Nautical Charts
  DTED: DTED Elevation Raster
  ELAS: ELAS
  ENVI: ENVI .hdr Labelled
  FIT: FIT Image
  GIF: Graphics Interchange Format (.gif)
  GTiff: GeoTIFF
  HDF4Image: HDF4 Dataset
  HFA: Erdas Imagine Images (.img)
  JPEG2000: JPEG-2000 part 1 (ISO/IEC 15444-1)
  JPEG: JPEG JFIF
  MEM: In Memory Raster
  MFF2: Atlantis MFF2 (HKV) Raster
  MFF: Atlantis MFF Raster
  NITF: National Imagery Transmission Format
  PAux: PCI .aux Labelled
  PCIDSK: PCIDSK Database File
  PNG: Portable Network Graphics
  PNM: Portable Pixmap Format (netpbm)
  VRT: Virtual Raster
  XPM: X11 PixMap Format

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When writing out GeoTIFF format for users of ESRI software or ImageMagick,
the band interleaving should be switched to pixel interleaving using
createopt="INTERLEAVE=PIXEL".

To specify multiple options use a comma separated list
(createopt="TFW=YES,COMPRESS=DEFLATE").

Out of the GDAL data types, the closest match for GRASS CELL, FCELL and DCELL
rasters are respectively Int32, Float32 and Float64. These are not exact
equivalents, but they will preserve the max possible data range and number of
decimal places for each respective GRASS raster data type. Please keep in mind, that
not all CELL rasters will require Int32 - e.g., 0-255 CELL raster are covered
by the Byte type as well. Moreover, some GDAL-supported formats do not
support all the data types possible in GDAL and GRASS. Use
r.info to check the data type and range for your
GRASS raster, refer to specific format documentation
(http://www.gdal.org/ - GDAL website, format vendor's docs) and
e.g. the Wikipedia article
http://en.wikipedia.org/wiki/C_syntax#Typical_boundaries_of_primitive_integral_types Typical boundaries of primitive integral types
for details.

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Export the integer raster roads map to GeoTIFF format:
        r.out.gdal input=roads output=roads.tif type=UInt16

Export a DCELL raster map in GeoTIFF format suitable for ESRI software:
        r.out.gdal in=elevation.10m out=ned_elev10m.tif type=Float64 createopt="INTERLEAVE=PIXEL,TFW=YES"

Export the floating point raster elevation map to ERDAS/IMG format:
        r.out.gdal input=elevation.10m output=elev_dem10.img format=HFA type=Float32

GDAL RELATED ERROR MESSAGES

         "ERROR 6: SetColorInterpretation() not supported for this dataset.": This may
 indicate that the color table was not written properly. But usually it will be
 correct and the message can be ignored.
        "ERROR 6: SetNoDataValue() not supported for this dataset.": The selected output format
 does not support "no data". It is recommended to use a different output format.
        "Warning 1: Lost metadata writing to GeoTIFF ... too large to fit in tag.": The color table metadata
  are too large. It is recommended to use a different output format.


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 http://www.gdal.org/formats_list.html GDAL supported formats page.

        r.out.ascii,
        r.out.arc,  
        r.out.bin,
        r.out.mat,
        r.out.png,
        r.out.ppm,
        r.out.tiff

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GDAL Pages: http://www.gdal.org


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Vytautas Vebra (oliver4grass at gmail.com)

Ïîñëåäíåå èçìåíåíèå: $Date: 2007-10-11 00:27:27 -0500 (Чт, 11 окт 2007)