[Wrf-users] Converting polar projection to mercator

[Don Morton]

I know this isn't directly relevant to WRF, but it seems like an
area that might be of interest to others and, besides, I could use
some guidance! :)

I'm currently running 2 48-hour forecasts per day for the Alaska
region ( http://weather.arsc.edu ), using polar stereographic
projection.  We're very interested - and I've already started a
student in this direction - of taking some of the output graphics
and using them as time-series overlays in a GoogleEarth and/or
NASA World Wind environment.  However, these overlays need
to be in  a mercator-like projection (you define the E and W
longitudes and the N and S latitudes).

I naively thought that it would be kind of trivial to take my wrfout
netCDF files (polar projection) and generate output in a mercator
projection via something like RIP, but now I'm thinking I was way
too optimistic.  I'm not very well versed on projections, but
theoretically (again, I'm being naive) it seems like all you need to
do is apply some sort of mathematical transformation from one
grid to another, though I can see where this might get hairy,
because your grid points would be different and you'd have to
interpolate, etc.,

Does anybody know of a way I might be able to do these conversions?
I stumbled across McIDAS, but it appears to me that this is probably
pretty costly?

Thanks,

Don Morton

-- 
Don Morton
Department of Computer Science
The University of Montana - Missoula
http://www.cs.umt.edu/~morton/