On Fri, Jan 18, 2013 at 5:11 PM, Jonsson <amen.alya...@bordeaux.inra.fr> wrote:
> <-raster("C:\\Users\\aalyaari\\Desktop\\SM_RE01_MIR_CLF31D_20100812T000000_20100812T235959_246_001_7.nc", > varname = "Soil_Moisture") > d: > class : RasterLayer > dimensions : 586, 1383, 810438 (nrow, ncol, ncell) > resolution : 0.2603037, 0.2916659 (x, y) > extent : -180, 180, -85.4581, 85.4581 (xmin, xmax, ymin, ymax) > coord. ref. : +proj=longlat +datum=WGS84 > names : Retrieved.soil.moisture.value > zvar : Soil_Moisture > a <- spTransform(d, CRS ("+proj=longlat +ellps=WGS84 +datum=WGS84 > +no_defs")) > but I got this error: > > Error in function (classes, fdef, mtable) : > unable to find an inherited method for function ‘spTransform’ > for signature ‘"RasterLayer", "CRS"’ > And what is the error telling you? That there's no method for spTransform that applies to RasterLayers. To transform a raster from one projection to another you need to use projectRaster from the raster package. Note that generally this can involve warping a raster and interpolating the new values to get a grid of cells in the new coordinate system. But... you were trying to do this: a <- spTransform(d, CRS ("+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs")) where d was: coord. ref. : +proj=longlat +datum=WGS84 - which is a no-op. The source and destination have the same coordinate reference system. You need to tell raster what the coordinate system of the source is. See ?projection - note this doesn't change the raster or do any projection, its just to tell the system what the coordinates in the data represent - lat,long or metres or whatever.. I looked in the HDR file and saw nothing about the projection, so I don't know how to specify what you've got. Also, you didn't point us to the .nc file you used in your example. Also also, you should probably be posting to R-sig-geo. Barry ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.