On Mon, 23 Oct 2006, bertrand toupin wrote: > Hi, earlier, I used those functions to transform a lat-long database to a > Lambert Azimuthal Equal Area (LAEA) : > > Lam_proj <- project(cbind(Grille$x, Grille$y),"+proj=laea > +lat_0=latitudem_grid +lon_0=longitudem_grid +x_0=0 +y_0=0 +a=6370997 > +b=6370997 +units=m") > > > Now that my calculations is done, I'd like to show the result and I'd need to > re-transform the LAEA database to a lat-long database (since "surfm" in > Matlab needs lat-long). > > I used : project(cbind(Prev$x, Prev$y),"+proj=latlong")
?project: and see inv= That is: project(cbind(Prev$x, Prev$y), proj=paste("+proj=laea", "+lat_0=latitudem_grid +lon_0=longitudem_grid +x_0=0 +y_0=0", "+a=6370997 +b=6370997 +units=m"), inv=TRUE)) > > But I got this error message : "latitude or longitude exceeded limits" Well, yes, you gave project() LAEA coordinates in metres, and asked it to project to +proj=longlat, which would be a null-op anyway, because project() only goes to (inv=TRUE) and from longlat. If you need objects that "remember" their coordinate reference systems, use sp classes and the spTransform() methods in rgdal. Roger > > Thanks for any help! > > > > --------------------------------- > > [[alternative HTML version deleted]] > > _______________________________________________ > R-sig-Geo mailing list > R-sig-Geo@stat.math.ethz.ch > https://stat.ethz.ch/mailman/listinfo/r-sig-geo > -- 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: [EMAIL PROTECTED] _______________________________________________ R-sig-Geo mailing list R-sig-Geo@stat.math.ethz.ch https://stat.ethz.ch/mailman/listinfo/r-sig-geo