Can one read multiple data variables (datavars) to one netCDF-derived Raster*? Can one write* from several Raster*'s to several datavars in one netCDF file? What I mean, why I ask:
I have a netCDF file with several datavars. One datavar (concentrations) is of primary interest, but I will need several of the other datavars to do subsequent computations on the concentrations datavar. The concs datavar is 3D (vertical level, latitude, longitude) but the others are either 2D (surface pressure, dims=(lat, lon)) or 1D (coefficients, dim=level). (There is only one timestep.) I also need to crop the horizontal extent of the datavars >= 2D in the file. This is easy with raster::crop(Raster*, ...), but it seems one can only construct a Raster* with one datavar per netCDF file: http://cran.r-project.org/web/packages/raster/raster.pdf > raster Create a RasterLayer object ... > Details ... > If x represents a NetCDF file, the following additional variable is > recognized: > varname: character. The variable name, such as ’tasmax’ or ’pr’. If > not supplied and the file has multiple variables are a guess will be > made (and reported) Am I missing something? If not, I'd like to know: 1. Must I create and crop separate Raster*s for each datavar? 2. Can I at least create/crop separate Raster*s for each of the dimensionalities: i.e., put the 3D datavars in one Raster* and put the 2D datavars in another Raster*? 3. A subsequent processor (apparently) finds it advantageous to have all the datavars in one netCDF file. Can one write from multiple Raster* to multiple datavars in a single netCDF file? An optimistic reading of raster.pdf suggests this is supported via the sequence [writeStart, writeValues, writeStop], but I'd appreciate confirmation. TIA, Tom Roche <[email protected]> _______________________________________________ R-sig-Geo mailing list [email protected] https://stat.ethz.ch/mailman/listinfo/r-sig-geo
