Hi there, I posted to this list a while back in the context that a few of us are working on better import/export capability of projected raster data into NetCDF CF-1 from the GDAL open source library - notes on our work are at http://trac.osgeo.org/gdal/wiki/NetCDF_exportUpdateChanges . These changes should make it through to the trunk of GDAL pretty soon.
So as well as letting people on this list know in case this is of general interest - we'd also really appreciate any help from people who are up with, or have examples of, some of the less common projections that CF-1 allows you to encode. Leaving aside the current discussions of possibilities of WKT and Datum support - we aimed to get as good a coverage of current CF-1.5 projections and their attributes as possible. This Wiki page gives a summary of status of where the projection support is at: http://trac.osgeo.org/gdal/wiki/NetCDF_ProjectionTestingStatus In particular, the Polar Stereographic CF-1 attributes have been a bit hard to 'map' to the CF-1 equivalents: If you look at http://www.remotesensing.org/geotiff/proj_list/polar_stereographic.html, there is a 'latitude of natural origin', but the CF-1.5 version specified that 'latitude_of_projection_origin' must be either +90 or -90 (to encode the pole). So I'm wondering if the CF-1 'standard_parallel' for this projection is the equivalent here? There were also issues with a few of the 'variants' of CF-1 projections, e.g. those that say you can used either a standard_parallel or scale_factor - listed at the bottom of the Wiki page linked above. In general my testing process has involved seeing if the exported projected rasters passes both the CF-checker, and also can be loaded and projected in the correct location in IDV, which uses NetCDF Java's on the backend and thus their implementation of CF-1 projection handling. I have attached our main testing sample to that Wiki page in both it's original UTM SRS, and also a Tarball of files exported in all the CF-1 projections so far. thanks, Patrick. BTW: I did look at the FGDC "Content Standard for Digital Geospatial Metadata" document referenced on the CF-1.5 App F page, but apart from specifying the attribute names for each projection, it didn't seem to help much with relating them to other map projection definition systems. ==== Patrick Sunter Victorian Partnership for Advanced Computing Senior Computational Scientist _______________________________________________ CF-metadata mailing list [email protected] http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
