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#107: CF Data Model 1.7 -----------------------------+---------------------------------------------- Reporter: markh | Owner: [email protected] Type: task | Status: new Priority: medium | Milestone: Component: cf-conventions | Version: Resolution: | Keywords: -----------------------------+---------------------------------------------- Comment (by jonblower): Replying to [comment:26 jonathan]: > The `grid_mapping` is so-called because of its original purpose, which is still its main purpose, of providing the mapping between 2D curvilinear (longitude, latitude) coordinates and the two horizontal dimensions of the grid (map projection coordinates or rotated lon-lat). Hi Jonathan - To my understanding it is the "coordinates" attribute that points to the curvilinear coordinates. The "grid_mapping" attribute points to something that looks like the definition of a projection (roughly speaking, the mathematical origins of the curvilinear coordinates, not the coordinates themselves), although we also use it for things that aren't projections, like rotated-pole CRSs. I wasn't keen on the idea of using "transform" because mostly one is not describing the transformation but a reference system. E.g. See the British National Grid example in the CF document. This (correctly) just describes the basis of the coordinate system but does not describe how to transform it to other systems. My view is that CRS is the most generic name for these descriptions and might be the most appropriate term to use in a data model. (This does not preclude, of course, the cases in which you really do have a transformation, but these are generally fairly complicated and hard to serialize and, as Jim says above, may not exist at all.) Best wishes, on -- Ticket URL: <https://cf-pcmdi.llnl.gov/trac/ticket/107#comment:28> CF Metadata <http://cf-pcmdi.llnl.gov/> CF Metadata This message came from the CF Trac system. To unsubscribe, without unsubscribing to the regular cf-metadata list, send a message to "[email protected]" with "unsubscribe cf-metadata" in the body of your message.
