Dear Etienne
Thanks for your helpful email, and sorry for slow response.
> Ok you mean that we could add new projections easily to the CF
> standard? That's great to know.
Yes, you could do this with a trac ticket, like ticket 72, which proposes to
add the geos projection. See
https://cf-pcmdi.llnl.gov/trac/query
> I'm not sure I understand your question - do you mean to ask if these
> additions to CF would be sufficient to describe most WKT definitions
> in pure CF metadata (without the WKT)?
Yes, that's what I mean. I'm interested to know how many other elements of WKT
are used in the cases you deal with.
> It seems that
> for many applications (especially at the scale most netcdf files are
> used for), TOWGS84 parameters are sufficient. A named datum would be
> nice, but there are quite a few different ways to identify datums (OGC
> vs ESRI).
OK. If they are standardised lists, we could provide attributes to store
them in.
> Here is a small compilation of the compatabilities between WKT (as
> GDAL sees it) and CF-1.5 projections, there are a few
> problems/unknowns with some projections:
> http://trac.osgeo.org/gdal/wiki/NetCDF_ProjectionTestingStatus
If you identify errors or inadequacies with CF definitions from your detailed
analysis, you could propose they be corrected, again with a CF trac ticket, in
this case as a "defect" rather than an addition to the standard.
> The following page lists WKT parameters:
> http://www.geoapi.org/2.0/javadoc/org/opengis/referencing/doc-files/WKT.html
Yes, this is a useful page.
> There are a few other parameters like VERT_CS, COMPD_CS and VERT_DATUM
> that some users may need.
The VERT_CS and VERT_DATUM appear to be names (in the Newlyn example). Are
these names standardised?
Best wishes and thanks for your help
Jonathan
Received on Tue Dec 13 2011 - 08:42:38 GMT
