Roman, Have you tried combinations of the functions 'edge', and 'distance' (and perhaps adjacency, if the 'amount' is expressed in cells rather than distance). Robert
On Thu, Nov 18, 2010 at 5:58 AM, Roman Luštrik <roman.lust...@gmail.com> wrote: > Dear list, > > I've been searching around and I continue to do so, but in the mean time I'm > seeking your advice on how to improve my approach. > > I'm using raster package and I'm trying to find cells around (let's call it > a buffer) and inside a polygon. These subsetted cells are used for > calculations later on. I'm basically trying to "grow" a polygon by a certain > specified amount. > > I have created a raster with values derived as 1:ncell(my.object), where > each value actually represents cell number and in a sense, position. This is > the playground for my polygon. > > So far, I've approached this by: > - find cell values inside the polygon (former raster::polygonValues) > - find cell values within the buffer of SpatialLines object (made from the > above polygon) (former raster::lineValues) > - find unique cell values from the above results > > The problem is that finding buffers around each cell on a line (second step) > is pretty RAM greedy. Would there be a more efficient way of "growing" a > polygon, preferably without using external software? > > > Cheers, > Roman > > > > -- > In God we trust, all others bring data. > > [[alternative HTML version deleted]] > > _______________________________________________ > R-sig-Geo mailing list > R-sig-Geo@stat.math.ethz.ch > https://stat.ethz.ch/mailman/listinfo/r-sig-geo > _______________________________________________ R-sig-Geo mailing list R-sig-Geo@stat.math.ethz.ch https://stat.ethz.ch/mailman/listinfo/r-sig-geo
