Sorry, I seem to have managed to get an empty message through yesterday.
I wanted to point out to John Wu that he should use a site list and
s.menu for his ground truth, but I saw several other messages giving the
same advice.
I also wanted to ask some attention for retrieving information from raster
maps within a certain radius from a point. Althought r.buffer usually does
the job, this may not be the case when you want information for individual
points; if they're closer to each other than the specified radius, the
buffer zones will overlap, not giving unique information within this radius.
I solved this in a script that did the following:
- read the site list one at a time
- run r.los with the site location as coordinate and the maximum distance
  as the radius on an empty raster-map
- r.mapcalc this map to a MASK that includes all of the 'viewshed'
- then run r.stats to get the data out of the rastermap

It seems a bit akward this way, and you get hundreds of line-of-sight maps
in your mapset. Has anyone ever thought about implementing a 'radius' option
in s.menu? The neighborhood-option (which gives a square area around a site)
is to me highly insatisfactory!

Philip Verhagen
Stichting RAAP
Plantage Muidergracht 14
NL-1018TV Amsterdam


