Jerry Nelson writes:
I am looking for a way to calculate the distance to the nearest road (or
other feature) for each pixel in a large raster. I can get this roughly with
r.buffer, but it takes a LONG time, presumably because it looks at each
pixel for each of the buffer distances. Does one of the other routines
do this?
Jerry,
r.cost does the same job if you take a cost input map filled with 1's (or
the value of your map's x-y resolution) and make a copy of your roads map
to be used as 'starting point' map. However, r.cost takes even more time
than r.buffer.... My experience with both programs is that the execution
time increases considerably if the maximum distance is very high.
So there's no easy solution to this one, just let your
machine run over the weekend. Good luck!
Philip Verhagen
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