On Thu, 26 Aug 2010, dkod wrote:
Roger Thank you for your quick and helpful response. I now have image/plot() working. I need some help in how to go from rectangular grid representation to a mercator (or other) projection. Since my source grid is 2 degree long/lat based, I'd like to use a projection. How do I get a proper projection? Here's the line I used: gr_sp <- SpatialGrid(grid=grd, proj4string = CRS(as.character(NA)))
No, much more work needed. If the input is in decimal degrees, geographical coordinates, and a known datum, you must warp (interpolate) to a planar projection. You might do this by projecting the input as a SpatialPointsDataFrame from +proj=longlat and known +datum to your target projection, then interpolate using your chosen interpolator to a grid defined in the target projection. A grid in geographical coordinates will effectively never be a grid in projected coordinates.
Roger
Sorry for such a basic question.
-- 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.biv...@nhh.no _______________________________________________ R-sig-Geo mailing list R-sig-Geo@stat.math.ethz.ch https://stat.ethz.ch/mailman/listinfo/r-sig-geo
