[GRASS-user] Projection Units and Values Negatively Affect r.topidx Results

[Rich Shepard]

   I discovered what I believe is a problem with the projection units on my
source DEM. They're in International Feet so the projection listing shows
32.something. That's the feet equivalent of 10m. What I'd like to learn is
how to change that value to 10.0 and the PROJ_UNITS to meters.

   When I run r.topidx with the supposed-10m DEM it completes in less than a
minute; 'g.region -p' shows me 2-million-plus cells. However, when I try to
run r.topidx on the 5m DEM there are 111-million-plus cells and it would
take at least 12 hours to complete. I suspect that the nominal 10m DEM is
actually computed as 32m resolution, not 32ft resolution.

   The disparity between the two is too great. There should be 4 times as
many cells at 5m resolution as there are at 10m.

   How can I change the base DEM from 32 feet to 10 metres? I know that I can
change the PROJ_UNITS value manually.

TIA,

Rich