[GRASSLIST:561] Working with r.surf.contour .....

Antonio G. - Geotronix nightnavigator at libero.it
Sun Jun 29 11:12:06 EDT 2003


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Hi.

I'm playing with r.surf.contour to see which is an acceptable resolution
for my DTM's without having to wait days for it to complete.
I noticed that if I create a 5 meter cell raster from v.to.rast I can
change resolution to a 10 m cell in g.region after creating the raster
contour line map and before creating the DEM. Obviously the DEM is 10 m
celled. However it looks real bad. Then I looked at the same iso contour
raster map (5m) I had created before, with the new resolution set to
10m. What I noticed was that the contour line where discontinous so
probably that is not a good way to work.

What I seem to understand is that if I create a 5^2 meter cell contour
rster map then I cannot change resolution before creating the DEM. The
DEM must also be at 5^2 resolution. Right?

However 5^2m cells take too much CPU time for creating a DEM and 10^2
cells create reaster contour maps that have the contours overlapping. I
presume this is no good as r.surf.contour assigns elevation in arbitrary
mode. Must I try various options in between 5 to 10 meters?
5 m is slow, 10 is fast but bad quality. Maybe 7.5 m is good compromise?

Bye

PS. Can I use r.surf.contour with the bash & carachter to send process
in background so that I can still continue working in v.digit?
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