<FONT face="Default Sans Serif,Verdana,Arial,Helvetica,sans-serif" size=2><DIV>Greetings</DIV><DIV>I'm using R 2.8 with recent (last month) versions of the packages I need to use at present.</DIV><DIV> </DIV><DIV>I'm interested in examining hierarchical spatio-temporal patterns in a data set. The data consist of 94 points (X, Y, UTM coordinates) at which catch rates for a fish were recorded and there are also estimates of prey available for these fish at the same locations. I have reason to believe that the relationships between predators and prey varies with spatial scale (nested processes).</DIV><DIV> </DIV><DIV>To test this hypothesis, I'd like to generate subsets of the points that are separated by distance ranges (1-50 km, 51-100 km, etc) so I can run Sncf (package ncf) on the subsets.</DIV><DIV> </DIV><DIV>I cannot find a way to do this with R code. Getting a distance matrix is easy. Using that to help generate a series of distance-based subsets is something I cannot figure out (without manually entering a list of all the point pairs).</DIV><DIV> </DIV><DIV>Any suggestions would be appreciated.</DIV><DIV>Dave Warner <BR></DIV><DIV>David Warner<BR>Research Fishery Biologist<BR>USGS Great Lakes Science Center<BR>1451 Green Road<BR>Ann Arbor MI 48105<BR>734.214.9392<BR></DIV></FONT>