Hi All
Are there any plans to replace the lzw compression algorithm in Grass with
something that is not patented?
Since Grass is a free software product, users publishing maps and graphics
and announcing they were made in Grass may risk to receive a $5000 bill
from Unisys, who owns the patent to LZW. Or am I just paranoid ...
Morten Hulden
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Morten Hulden wrote:
Hi All
Are there any plans to replace the lzw compression algorithm in Grass with
something that is not patented?
Since Grass is a free software product, users publishing maps and graphics
and announcing they were made in Grass may risk to receive a $5000 bill
from Unisys, who owns the patent to LZW. Or am I just paranoid ...
Morten Hulden
I do not think you are paranoid. The problem is at least real. Just in case
on http://www.gnu.org/philosophy/gif.html there is a deep discussion on
this topic and pointers to alternative free compression algorithms.
But I also think that due to its diffusion it will be difficult to get rid of
LZW.
Should think about that.
Luca
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--
--> Luca Palmeri - Dip. Proc. Chimici dell'Ingengeria
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--> Think holistic @ the end of the 2nd millenium <--
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On Tue, Nov 09, 1999 at 06:21:47PM +0100, Luca Palmeri wrote:
Morten Hulden wrote:
> Are there any plans to replace the lzw compression algorithm in Grass with
> something that is not patented?
Where exactly uses GRASS LZW compression?
We have to identify this first.
> Since Grass is a free software product, users publishing maps and graphics
> and announcing they were made in Grass may risk to receive a $5000 bill
> from Unisys, who owns the patent to LZW. Or am I just paranoid ...
I do not think you are paranoid. The problem is at least real.
I agree.
Bernhard
--
Research Assistant, Geog Dept UM-Milwaukee, USA. (www.uwm.edu/~bernhard)
Free Software Projects and Consulting (intevation.net)
Association for a Free Informational Infrastructure (ffii.org)
Bernhard Reiter wrote:
On Tue, Nov 09, 1999 at 06:21:47PM +0100, Luca Palmeri wrote:
> Morten Hulden wrote:
> > Are there any plans to replace the lzw compression algorithm in Grass with
> > something that is not patented?
Where exactly uses GRASS LZW compression?
We have to identify this first.
One place I can recall right now is r.in.tiff that requires the tiff to be in
compressed in LZW.
I do not know about the internal compression algorithm for raster maps
Luca
--
--> Luca Palmeri - Dip. Proc. Chimici dell'Ingengeria
Universita' di Padova TEL: +390498275527 -------
------------------------- FAX: +390498275528 -------
--> Think holistic @ the end of the 2nd millenium <--
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On Tue, 9 Nov 1999, Bernhard Reiter wrote:
Where exactly uses GRASS LZW compression?
We have to identify this first.
Running this in grass src directory
find . -type f -name "*\.[ch]" -exec grep -l lzw {} \;
will show at least these files have something to do with lzw
./include/gisdefs.h
./libes/g3d/G3d_intern.h
./libes/g3d/fpcompress.c
./libes/g3d/g3ddefaults.c
./libes/g3d/g3dopen.c
./libes/g3d/headerinfo.c
./libes/gis/G.h
./libes/gis/closecell.c
./libes/gis/get_row.c
./libes/gis/lzw.c
./libes/gis/put_row.c
./libes/gis/G_dump.c
./raster/r.tiff/tools/lzwcodes.c
./raster/r.tiff/tools/pal2rgb.c
./raster/r.tiff/tools/ras2tiff.c
./raster/r.tiff/tools/sgisv.c
./raster/r.tiff/tools/tiffcp.c
./raster/r.tiff/tools/tiffmedian.c
Morten Hulden
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On Tue, Nov 09, 1999 at 11:13:48PM +0100, Morten Hulden wrote:
On Tue, 9 Nov 1999, Bernhard Reiter wrote:
> Where exactly uses GRASS LZW compression?
> We have to identify this first.
Running this in grass src directory
find . -type f -name "*\.[ch]" -exec grep -l lzw {} \;
will show at least these files have something to do with lzw
./include/gisdefs.h
./libes/g3d/G3d_intern.h
./libes/g3d/fpcompress.c
./libes/g3d/g3ddefaults.c
./libes/g3d/g3dopen.c
./libes/g3d/headerinfo.c
./libes/gis/G.h
./libes/gis/closecell.c
./libes/gis/get_row.c
./libes/gis/lzw.c
./libes/gis/put_row.c
./libes/gis/G_dump.c
This can't be that hard to fix. 
But it might mean that we need to change some dataformats.
./raster/r.tiff/tools/lzwcodes.c
./raster/r.tiff/tools/pal2rgb.c
./raster/r.tiff/tools/ras2tiff.c
./raster/r.tiff/tools/sgisv.c
./raster/r.tiff/tools/tiffcp.c
./raster/r.tiff/tools/tiffmedian.c
Okay, we can't change the tiff stuff, but we might let that handle
the tiff library somehow.
--
Research Assistant, Geog Dept UM-Milwaukee, USA. (www.uwm.edu/~bernhard)
Free Software Projects and Consulting (intevation.net)
Association for a Free Informational Infrastructure (ffii.org)