Hi Dominic, all,
Dominic Lowe wrote:
But that's not to say the CF community shouldn't also invest time in defining
resolvable coordinate reference systems specific for our needs.
I think CF already has a pretty good handle on defining the CRS used by
a data variable in the data file. Each coordinate variable defines some
of the CRS information in its attributes and the grid mapping variable
defines the horizontal CRS to some degree. There are certainly places
that need some additions and refinement (like vertical datum). But in
other ways CF is ahead of OGC, e.g., already handling pressure and sigma
vertical coordinates.
Though not explicitly a CRS definition language, either CDL or NcML (and
knowledge of CF) could be used to export the CRS information. Do we need
to come up with a more explicit way of encoding a CRS definition?
When it comes to OGC interoperability, being able to encode the CRS
information we already have into GML seems key. [And of course,
extending the CF ability to capture some important CRS details. Oh, and
probably extending beyond grid mapping names (projection method
identifiers) our set of CRS related controlled vocabularies. But other
than that ... ;-)]
Ethan
--
Ethan R. Davis Telephone: (303) 497-8155
Software Engineer Fax: (303) 497-8690
UCAR Unidata Program Center E-mail: edavis@xxxxxxxx
P.O. Box 3000
Boulder, CO 80307-3000 http://www.unidata.ucar.edu/
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