On Thu, 5 Apr 2007, Vladimir Eremeev wrote: > > If your country or state borders are polygons or polylines, you could > convert them to desired projection using the function project from the > package rgdal. > > Latitude-longitude grid also could be added by generating desired > polylines in lat-lon and converting them to the desired projection using > project. >
Yes, the route would be to plot the image in its native projection, and project the vector data (shorelines, countries) to the same projection. Similar topics have been discussed on the R-sig-geo list, including the reading of netcdf files (which are a bit picky) with functions in the rgdal package which import the coordinate reference system directly. Please follow this up on R-sig-geo if you need more help. > > Linda Smith wrote: > > > > I have a netcdf gridded file with LCC projection. I can easily use > > image.plot to visualize it. However, as the axises are in X,Y, not Lat and > > Lon, I could not add state or country maps onto it (or lat lon > > information). > > I do have a grid2d file that describes the lat and lon for each (X,Y) > > grid, > > but the lat and lon are not regularly spaced, so I could not use > > image.plot. > > > > Does anyone know how to plot this type of gridded data so that country or > > state borders can be easily added? Thanks a lot! > > > > What do you mean by "grid2d file that describes the lat and lon for each > (X,Y) grid"? > If this are two rasters of the same size having corresponding latitude and > longitude values in each raster cell, then you could use contourLines to get > lat-lon grid. However, you, probably, will want to smooth it. > -- 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] ______________________________________________ [email protected] 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.
