Ticket #1384 (closed defect: fixed)
Support TIFF files with improperly scaled colortable values
|Reported by:||izzybitsie@…||Owned by:||warmerdam|
Description (last modified by hobu) (diff)
"TIFF colors maps are supposed to have colors in the range 0-65535 for each component instead of the usual 0-255 in other formats. If geotiff file has been incorrectly generated to have the colormap between 0 and 255, GDAL converts it to 0-255 values (roughly by dividing by 256) so everything ends up black. This may be a fairly common failure with tiff generators and that some applications may have special logic to look for files with all colormap values in the 0-255 range and avoid the rescaling that should happen." Explanation offered by Frank Warmerdam to problem reported in gdal-dev forum. Input image of the type mentioned can be downloaded from : http://www.mediamax.com/izzybitsie/Hosted/AS_GMSNO_00_20061122205548.tif.gz When using gdal_merge.py to mosaic several images of this type a black map is obtained as output.
Note: See TracTickets for help on using tickets.