Re: polygons

From: Mary Haley <haley_at_nyahnyahspammersnyahnyah>
Date: Tue, 21 Jul 2009 16:03:24 -0600 (MDT)

We've been corresponding offline about this question. Michael was able
to use the "gc_inout" function which determines if a specified point
is inside or outside of a spherical polygon.

Hopefully we'll post an example at some point.


On Sat, 18 Jul 2009, MICHAEL NOTARO wrote:

> I have a shapefile with a bunch of individual polygons and the associated
> lat/lons for many points defining each polygon. I have already been able
> to reach those values into NCL. They define the area of N. America
> covered by a specific tree specie.
> Now I want to generate a 0.25x0.25 degree grid with 1's if the tree is found
> there and 0's if the tree is not. So, basically I need to know if each 0.25 degree
> grid cell is within these polygons, meaning the tree is found there.
> Could anyone recommend a method to do this? I have some ideas but none that
> seem very satisfactory or won't take forever to run (actually I need to do this
> for 170 tree species). The main challenge is knowing if a grid cell is within a polygon
> of points and then repeating this for each grid cell and all polygons.
> Thanks, Michael
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Received on Tue Jul 21 2009 - 16:03:24 MDT

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