[GRASSLIST:9094] Potential Mapping

[Trevor Wiens]

I was asked by a colleague the other day about potential mapping in GRASS. I've seen the v.kernel algorithm, but AFAIK it only calculates density. Back in the old days of SPANS, there was a wonderful tool called popmap, which would let one set two buffers around a series of points. Within the first buffer the value would be set to the value of the point. Within the second buffer you could specify the decay curve to be linear, exponential, etc. In areas of overlap however, one could specify any operation (like r.mapcalc in GRASS). The beauty of this technique over kriging for instance is that one can generate a partial surface, rather than needing to generate a surface for which one might not have all the necessary data points. Further being able to generate standard deviations rather than just density can be valuable in identifying problem areas.

I'm sure there would be a way to replicate this functionality in GRASS, but I'm not sure what to recommend. As of right now, this individual still has his copy of SPANS running, but since the product is no longer developed, he is wanting another tool to do this. 

Any suggestions would be appreciated. I'm thinking that it should be possible to build a shell script to duplicate this functionality in a number of steps, but I'm not sure the best way to proceed. 

T
-- 
Trevor Wiens 
twiens at interbaun.com

The significant problems that we face cannot be solved at the same 
level of thinking we were at when we created them. 
(Albert Einstein)