[GRASS5] rasters?

[Glynn Clements]

Andrea Antonello wrote:

> we from the JGrass project have a problem with raster reading in the new GRASS 
> releases. Since end of 2005 some people reported problems with raster 
> reading.
> I'm trying to track the problem down, but I really need some help. The bux 
> happens on the raster row decompression.
> Markus already helped me with a bugfix that was made by Glynn on compression 
> of CELL files. That could one part of the problem but the bug happens to us 
> also in the FCELL case. Since the code is pretty complicated I would like to 
> collect some ideas before I dive into it, risking to get some more white 
> hairs.

What are you asking, exactly?

GRASS floating-point rasters are encoded using XDR, then (optionally)
compressed with zlib.

For data which is compressed (according to the "compressed" field in
the cellhd file), each row begins with a flag byte which indicates
whether the data for that row is actually compressed; a value of 48
(ASCII code for '0') indicates uncompressed data, 49 (ASCII code for
'1') indicates compressed data.

For uncompressed data, there is no flag byte.

-- 
Glynn Clements <glynn at gclements.plus.com>