What is your budget/level of need? I would export the polygons to mif/mid ( http://www.mp2kmag.com/importersub01.asp ) and then attempt this in a GIS software package.

My tool of choice is MapInfo ($1500) but there are some cheaper ones like Caliper's Maptitude and Manifold.

There may be a way to do this with MapPoint and VB/C only -- certainly with raw GIS algorithms/math, but I don't really have a suggestion there but if I had to do it, I'd explore freegis.org first, also the Ed William's Aviation Formulary.

(for all suggestions use Google, I think they will take you right there).

Eric

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