P.S. The solution I just posted assumes the earth is a sphere, not an ellipsoid (which would be more accurate).
> These are projected, not geographical coordinates, unfortunately. The case > for calculating areas on an ellipsoid is much harder, I'm afraid. > > Roger On Wed, Apr 28, 2010 at 4:16 AM, Roger Bivand <roger.biv...@nhh.no> wrote: > On Wed, 28 Apr 2010, Paul Hiemstra wrote: > >> Tim Erbrecht wrote: >>> >>> Dear all, >>> >>> >>> having data in a SpatialGridDataFrame with geographic coordinates, is >>> there a simple method to calculate the spatial area for each cell? I wasn't >>> able to find anything in the list archives ... >>> >>> >>> Thanks and best regards >>> >>> Tim >>> >>> ------------------------------------------------------------------------ >>> >>> _______________________________________________ >>> R-sig-Geo mailing list >>> R-sig-Geo@stat.math.ethz.ch >>> https://stat.ethz.ch/mailman/listinfo/r-sig-geo >>> >> with the meuse dataset: >> >> library(sp) >> data(meuse.grid) >> gridded(meuse.grid) = ~x+y >> fullgrid(meuse.grid) = TRUE >> bla = gridparameters(meuse.grid) >> area = bla$cellsize[1] * bla$cellsize[2] >> area > > These are projected, not geographical coordinates, unfortunately. The case > for calculating areas on an ellipsoid is much harder, I'm afraid. > > Roger > >> >> cheers, >> Paul >> >> > > -- > 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 > _______________________________________________ R-sig-Geo mailing list R-sig-Geo@stat.math.ethz.ch https://stat.ethz.ch/mailman/listinfo/r-sig-geo
