Lat/Lon to Polar: Revisited


With all these great examples of dynamic map projections, it reminded me of something I tried a couple of years ago. I have several netCDF terrain files that are read into VisAD as ((Longitude, Latitude) -> Altitude). I have an EarthLocationTuple (radar site) that is located in the (lat/lon) center of each terrain file.

I can use Radar"X"DCoordinateSystem to get an az/ran for each lat/lon gridpoint of my terrain file. I would like to create a corresponding set of ((Range, Azimuth)->Altitude) netCDF files for each of the original terrain files. Doing this would hopefully speed up many calculations - or at least simplfy my code by eliminating the lat/lon -> az/ran conversion.

My problem is that I don't know how to construct the data set so that VisAD can read/plot the az/ran data. I am unsure whether to try to create the domain [either (Range, Azimuth) or (Azimuth, Range)] as a Gridded2DSet, Irregular2DSet, or what. I have tried both. The Gridded2DSet fails saying that I do not have a valid grid (apparently when azimuth goes from 359 -> 0 degrees). The Irregular2DSet takes way to long and runs out of heap space (even when I set it to 512 Mb). So I guess my main question is how do I construct my domain set to be a valid grid composed of radar-centric polar coordinates - if it is even possible?

Also, I assume that I would set my ScalarMaps to Display.Radius (Range) and Display.Longitude (Azimuth), but do I set my RealTypes (Range and Azimuth) to RealType.Radius and RealType.Longitude also?

Thanks so much for any insight anyone can provide!


Kevin L. Manross        [KD5MYD] <><          (405)-366-0557
CIMMS Research Associate               kevin.manross@xxxxxxxx

"My opinions are my own and not representative of CIMMS, NSSL,
NOAA or any affiliates"

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