SpatialPixel and SpatialPoints Overlay output
On Fri, 26 Oct 2007, Michal Gallay wrote:
Hello R User's, I am struggling with overlaying 2 rasters datasets. Both were ASCII grids and loaded via read.asciigrid. One as SpatialPixelDataFrame and another converted to SpatialPointsDataFrame. The are shifted with respect to each other and the aim is to get the values from raster1 in the overaly region with raster2. However, the overaly does not give the values which are in raster1 at data, but the values' order(position in the vector). Could anyone advise why is that? Is there a simple way how to actually clip them according to the overlay region?
In general (not just in this context, but for many non-spatial objects too), use the [ operator: raster1 at data[o,] to extract the values as a data frame for the o indices returned by overlay(), or (most likely) raster1 at data[o, 1] as a vector. Roger
Thank you very much. Regards, Michal
Roger Bivand Economic Geography Section, Department of Economics, Norwegian School of Economics and Business Administration, Helleveien 30, N-5045 Bergen, Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43 e-mail: Roger.Bivand at nhh.no