Dear Justin > sea_floor_depth_below_reference_datum (positive down) looks fine to me.
Isn't this the same thing: > bathymetry_below_reference_datum (postive down) "bathymetry" means sea-floor depth, doesn't it? For consistency with other stdnames, in particular height_above_reference_ellipsoid sea_surface_height_above_reference_ellipsoid this one > topography_above_reference_datum (postive up) should be surface_height_above_reference_datum I think. > Furthermore, I'd also propose that any of these 3 would be required > to have metadata with them (e.g. NetCDF attribute) which > specifically defines the reference datum. This metadata would be > called "VerticalDatum" (IOOS uses this) and would have a syntax like > the following for NAVD88: > urn:ogc:def:datum:epsg::5103 We did talk quite a lot about this when Phil Bentley proposed the extensions which we adopted for grid_mapping to describe the ellipsoid etc. The discussion stalled because we didn't really understand what "vertical datum" means! As you and I have been discussing separately, if NAVD88 is a geoid, I think we should call it a geoid in the standard name, and we should extend grid_mapping so it can identify the geoid by name, perhaps also giving a URN as you say. Unlike the ref ellipsoid, the geoid cannot be specified by metadata, as it's too complicated! best wishes Jonathan _______________________________________________ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata