Dear List, I need to carry out an IDW interpolation of precipitation values within a basin. I want to obtain the mean value in each one of the subcatchments, which are defined as polygons in a shapefile.
I would like to know: How can I transform the subcatchments polygons (class "SpatialPolygonsDataFrame" ) into a "data.frame" that can be used by the "block" parameter of the "krige" function ? So far, I've tried: 1) SubCatchments.shp <- readShapePoly(SubCatchmentsShp.fname, proj4string=p4s) 2) centroids <- coordinates(SubCatchments.shp) 3) pp.idw.block <- krige(value~1, locations=centroids, block=SubCatchments.shp) Steps 1 and 2 are ok, but in step 3 I get the error: Error en function (classes, fdef, mtable) : unable to find an inherited method for function "krige", for signature "formula", "matrix" because "SubCatchments.shp" class is "SpatialPolygonsDataFrame' and not 'data.frame' Any help will be appreciated. Thanks in advance, Mauricio -- ============================================= Linux user #454569 -- Ubuntu user #17469 ============================================= "A journey of a thousand miles begins with a single step" (Lao Tse) _______________________________________________ R-sig-Geo mailing list R-sig-Geo@stat.math.ethz.ch https://stat.ethz.ch/mailman/listinfo/r-sig-geo