Hi Etienne and others interested in NetCDF driver, I did some work on WMS display of NetCDF files generated by GDAL today, and it gave me a chance to play around with & think about how to handle the Datum issue as described at http://trac.osgeo.org/gdal/wiki/NetCDF_Improvements#Datumissues .
Here's a first cut suggestion of how GDAL should behave when writing a new NetCDF file using gdal_translate: * Keep saving the current datum info, with names e.g. WGS84, as part of the WKT that GDAL saves in it's special "spatial_ref" attribute. * But _also_ save the actual spheroid parameters for the datum in use in attributes CF-1 can read, e.g. semi_major_axis, semi_minor_axis, and inverse_flattening. Then on import, GDAL would look for its "spatial_ref" by default as authoritative for datum info, but could use the CF-1 as a backup. This would parallel the way projection parameters are handled in the NetCDF driver, i.e. writing WKT in the 'spatial_ref' attribute, but also writes duplicate CF-1 convention ones if possible to help with display of the file in NetCDF tools and things like THREDDS. Perhaps this could be a passable option to the driver whether you write the duplicate CF-1 datum info or not, with default to on. (That is, unless the CF conventions have plan to support named datums coming up imminently?) cheers, Patrick. _______________________________________________ gdal-dev mailing list gdal-dev@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/gdal-dev