Retrieving values at select coordinates from HDF Swath data

I would like to build a function that reports the value of an HDF swath
data variable at a specific coordinate location (over and over again for
different files). Since swath data has different pixel locations (and
sizes) for every file, so I cannot simply report the value of a
predefined grid location.

I have 2 methods in mind that would both work: 1) I can grid the data
first, and then report the value from known (i,j) location, or 2) I can
index the lat2d and lon2d attributes, calculate the distance of each
pixel from my coordinate of interest, and then pick the value from the
pixel that is closest.

Option 1 can lead to slight variance in data values, and seems too
intensive for such a simple need. Option 2 would be less intensive, and
more accurate, but I'm hoping someone might know of a simpler method?

In other words, is there a way for NCL to find a grid point location in
swath data that falls over a specific coordinate so that a single value
can be reported?

Thank you for your insight!
-Farren
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Received on Fri Apr 6 16:35:12 2012