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?
Thanks,
Chris Fonnesbeck
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Christopher J. Fonnesbeck ( c h r i s @ f o n n e s b e c k . o r g )
Georgia Cooperative Fish & Wildlife Research Unit, University of Georgia
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?
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Glynn Clements <glynn.clements@virgin.net>