[GRASSLIST:4604] Re: different CELL integer types?

[Glynn Clements]

William K wrote:

> Disappointing.  I understand not being able to change the existing 
> format, but what about adding 1 and 2 byte signed cell formats?  When 
> dealing with elevation data this can save everyone a lot of storage 
> space (and probably speed up disk access some).

That's one of the objectives for my planned next-generation raster I/O
system. But that won't be happening soon.

For the time being, in the most recent 5.3 CVS version, you may be
able to reduce disk space further by setting the environment variable
GRASS_INT_ZLIB (to anything). That will cause newly-created integer
raster maps to use zlib (gzip) compression rather than RLE
compression. However, such maps won't be readable with older versions
of GRASS.

Alternatively, you could shift the elevations so that the stored
values are never negative, and create a reclass map to correct the
elevations.

-- 
Glynn Clements <glynn.clements at virgin.net>