This will affect all GRASS 5 versions later than beta10 (CVS was updated Jan 18 2001)
Because of the UNISYS patent (http://www.unisys.com/unisys/lzw/) on the LZW compression algorithm, on January 18 2001, GRASS 5 library code no longer uses this method to compress floating point rasters and G3D files. Unfortunately, this creates an incompatible change for persons using earlier versions of GRASS 5.0 (GRASS 5 beta1 to beta10 users).
Note: This LZW removal does NOT affect
How to migrate your GRASS 5 floating point raster maps:
Generally the conversion is a two-step procedure (see below for one step):
How to migrate your GRASS 5 G3D raster voxel maps:
The GRASS 5.0 Development Team apologizes for this inconvenience.
We provide two ways to convert your data:
1. Two-step conversion: Requires old and new GRASS.
fp_uncompress.sh: uncompress all
raster maps. Save and run within your old GRASS 5:
This scripts will decompress all maps within a location.
Run this within all locations you have!
Finished with all GRASS 5 locations you have? O.k., now upgrade to the non-LZW GRASS 5 (beta11 or later as well as GRASS CVS version).
fp_recompress.sh: recompress all
raster maps with DEFLATE. Save and run within new GRASS 5:
This scripts will compress back all maps within a location in
That’s it. Welcome to the patent-free GRASS 5.
2. One-step conversion: Does not require old GRASS, simply run in new GRASS 5beta11 (or later). So you don’t need the old GRASS 5:
r.lzw2z changes the compression on-the-fly within the new GRASS 5.0beta11 (or later):
Proceed to Download latest GRASS 5.0.x
So: Did you read above? Did you download r.lzw2z or the fp_*.sh scripts if you are already using GRASS 5? If so, please proceed:
Jan 18 2001, © GRASS Development Team, last update: June 12, 2001