Re: plot irregularly gridded map data

[davidf(at)dfanning.com (David Fanning)]

Tom Spisz SRM (tom.spisz@jhuapl.edu) writes:

> I have an irregularly gridded latitude/longitude data set.  Although the
> data is in a polar (radius, azimuth) format like a radar swath, I have
> the exact lat/lon position for each point.  I cannot plot the data using
> map_image because that requires a regular grid.  I used map_patch
> successfully on small portions of the data.  Unfortunately, any attempts
> to plot larger portions of the data using map_patch result in the error:
> 
>  % TRIANGULATE: Points are co-linear, no solution.
> % Error occurred at:  MAP_PATCH         181
>   /usr/local/rsi/idl_5.2/lib/map_patch.pro
> 
> Does anyone know:
>   a) how to plot this type of "radar swath" data onto a map?
> or
>   b) how to sort the data in a way to work around the problem of
> "co-linear" points?

I've always recommended Liam Gumley's ImageMap program
for this kind of mapping. I don't think it gets much
better than that. :-)

   http://cimss.ssec.wisc.edu/~gumley/imagemap.html

Cheers,

David

-- 
David Fanning, Ph.D.
Fanning Software Consulting
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