#168: Addition of grid mapping for radar and lidar data in radial coordinates
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Reporter: mikedixon | Owner: cf-conventions@…
Type: enhancement | Status: new
Priority: medium | Milestone:
Component: cf-conventions | Version:
Resolution: | Keywords: radar lidar grid mapping
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Comment (by jonathan):
Dear Mike
Thanks for pasting in the proposal. That's very helpful.
> I don't really follow your assertion that the mapping of a radar return
to a location in space is dependent on measured and variable physical
quantities.
That was what I understood by your text, "The location in space,
especially in the vertical, is dependent on the propagation of the energy
through the atmosphere. Vertical gradients of the index of refraction lead
to complexities in determining the height of the target." That sounds like
some physics is needed to work out the xyz locations, not just geometry -
I agree that geometry is needed too, of course. Did I misunderstand this?
To be consistent with CF it would be good to include the latitude,
longitude and height coordinates in the file, as well as the polar
coordinates. That makes the data more easily usable by generic
applications. It's the reason why CF requires 2D latitude and longitude
auxiliary coordinate variables for data variables which are on map
projection planes. Auxiliary coordinates can be understood without a
grid_mapping. The grid_mapping additionally provides the information to
compute the relationship between the grid coordinates (the polar
coordinates, in your case) and the geolocated (auxiliary) coordinates, for
software which is able to do that. Perhaps that's your aim. Are your
grid_mapping attributes specifying the location of the radar/lidar source?
What else is needed to compute the geolocated coordinates from the polar
coordinates?
Best wishes
Jonathan
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Ticket URL: <https://cf-trac.llnl.gov/trac/ticket/168#comment:8>
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