[GRASSLIST:2262] Re: r.thin instability

[Glynn Clements]

Christopher Fonnesbeck wrote:

> I have been trying to run r.thin on a 30000x30000 raster in order to 
> develop a stream network, but am suffering instability problems on 3 
> different machines. On 2 linux boxes, I get an error writing a 
> temporary file, while on an OSX machine I get a bus error. All machines 
> are running GRASS 5.7 compiled from a very recent CVS. Does anyone have 
> experience with either of these errors and how to circumvent them?

r.thin tries to copy the entire map to a temporary file, using 4 bytes
per cell. For a 30000x30000 raster, this would require a 3.6Gb file. 
On a 32-bit system, handling files larger than 2Gb is problematic; you
generally have to use a separate programming interface to access such
files.

The only workaround would be to split the map into sections and thin
each section separately.

Is the MacOSX system 64-bit (i.e. is C's "long" 64 bits)? Do you still
get the bus error on smaller maps?

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