Dear Jonathan, It depends. In the best case you can change the resolution of raster2 with 'aggregate' or 'disaggregate' (or a combination); and change its extent with 'expand' or 'crop'.
In other cases, for example if the origin of the rasters also differ, it may be necessary to resort to 'resample' to change the origin (and perhaps cells size and extent at the same time). Some raster algebra will actually work for rasters with different extents, as long as they overlap at least partly, and their origin and resolution are the same (the extent of the raster returned is the intersect of the input rasters) Robert On Mon, May 24, 2010 at 7:35 PM, Jonathan Greenberg <greenb...@ucdavis.edu> wrote: > R-sig-geo'ers: > > Given two rasters of differing resolutions, extents, and cell sizes, > what is the most efficient way to do some level of raster algebra on > the files, e.g.: > > raster1=raster(file1) > raster2=raster(file2) > > I would like to add raster1 + raster2 and have the output be the > extent, cell size and projection of file1. My understanding is > raster()'s map algebra requires the same size/projection of the > inputs, correct? Thanks! > > --j > _______________________________________________ R-sig-Geo mailing list R-sig-Geo@stat.math.ethz.ch https://stat.ethz.ch/mailman/listinfo/r-sig-geo
