spTransform cannot reproject a grid - this will (usually) requires destructive resampling of the data to a completely new grid. There are functions in the raster package to do this: projectRaster.
I think this would work, but there may be important details that you will need to investigate: raster.eugrd025 <- raster(eugrd025) eugrd025EFDC <- projectRaster(raster.eugrd025, CRSobj=CRS(projection(eugrd025EFDC_SPDF))) On Fri, Jul 2, 2010 at 1:40 AM, Agustin Lobo <alobolis...@gmail.com> wrote: > Hi! > > I use spTransform to reproject: > >> class(eugrd025) > [1] "SpatialGrid" > attr(,"package") > [1] "sp" > >> projection(eugrd025) > [1] "+proj=longlat +ellps=WGS84" > >> eugrd025EFDC <- spTransform(eugrd025, >> CRSobj=CRS(projection(eugrd025EFDC_SPDF))) > >> projection(eugrd025EFDC) > [1] "+proj=laea +lat_0=52 +lon_0=10 +x_0=4321000 +y_0=3210000 > +ellps=GRS80 +units=m +no_defs" > > This is good, but: >> class(eugrd025EFDC) > [1] "SpatialPoints" > attr(,"package") > [1] "sp" > > Why is the class changed to SpatialPoints? I need a grid object for >> eugrd025EFDCr <- raster(eugrd025EFDC) >> Br025 <- resample(Br,eugrd025EFDCr) > > don't I? > > I also have the problem that the CRS of eugrd025EFDCr is not conserved: >> projection(Br) > [1] "+proj=laea +lat_0=52 +lon_0=10 +x_0=4321000 +y_0=3210000 > +ellps=GRS80 +units=m +no_defs" > >> projection(eugrd025EFDC) > [1] "+proj=laea +lat_0=52 +lon_0=10 +x_0=4321000 +y_0=3210000 > +ellps=GRS80 +units=m +no_defs" > >> projection(eugrd025EFDCr) > [1] "NA" > > which I fix with >> projection(eugrd025EFDCr) <- CRS(projection(eugrd025EFDC)) > > and repeat >> Br025 <- resample(Br,eugrd025EFDCr) > > Anyway, I get a much coarser raster than I want: >> dim(Br025) > [1] 10 10 1 > > because >> dim(eugrd025EFDCr) > [1] 10 10 1 > > While it should be 180x100: > >> summary(eugrd025EFDC) > Object of class SpatialPoints > Coordinates: > min max > s1 2498538 6561151 > s2 1327858 4313263 > Is projected: TRUE > proj4string : > [+proj=laea +lat_0=52 +lon_0=10 +x_0=4321000 +y_0=3210000 +ellps=GRS80 > +units=m +no_defs] > Number of points: 18000 >> dim(Br025) > [1] 10 10 1 > >> summary(eugrd025) > Object of class SpatialGrid > Coordinates: > min max > coords.x1 -10.125 34.875 > coords.x2 34.875 59.875 > Is projected: FALSE > proj4string : [+proj=longlat +ellps=WGS84] > Number of points: 2 > Grid attributes: > cellcentre.offset cellsize cells.dim > 1 -10 0.25 180 > 2 35 0.25 100 > > Is eugrd025EFDCr wrong because class(eugrd025EFDC) has been changed > from SpatialGrid to SpatialPoints? > > Agus > > _______________________________________________ > 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
