[Gdal-dev] GeoTIFF and CCITTRLE compression

[Markus Neteler]

Hi,

I was asked to fix some ArcInfo generated TIF/TWF files
to Geotiff to include the projection info.

Original header:

Driver: GTiff/GeoTIFF
Size is 26508, 22992
Coordinate System is `'
Origin = (1680792.312782,5091252.448363)
Pixel Size = (0.25000000,-0.25000000)
Metadata:
  AREA_OR_POINT=Point
  TIFFTAG_SOFTWARE=Arc/Info
  TIFFTAG_XRESOLUTION=0.039000001
  TIFFTAG_YRESOLUTION=0.039000001
  TIFFTAG_RESOLUTIONUNIT=3 (pixels/cm)
Image Structure Metadata:
  COMPRESSION=CCITTRLE
Corner Coordinates:
Upper Left  ( 1680792.313, 5091252.448) 
Lower Left  ( 1680792.313, 5085504.448) 
Upper Right ( 1687419.313, 5091252.448) 
Lower Right ( 1687419.313, 5085504.448) 
Center      ( 1684105.813, 5088378.448) 
Band 1 Block=26508x3 Type=Byte, ColorInterp=Palette
  Metadata:
    NBITS=1
  Color Table (RGB with 2 entries)
    0: 255,255,255,255
    1: 0,0,0,255

Using
gdal_translate -a_srs EPSG:26591 -co COMPRESSION=CCITTRLE ...
does not quite work since CCITTRLE isn't supported (AFAIK).
Also the color table is expanded a lot to 0..255.

My questions are:
- how to compress in a similar way (since we cannot preserve CCITTRLE)?
- is the color table expansion harmful (it looks ok, but will it be
  understood everywhere)?

thanks,
Markus