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Re^3: Speeding up point-in-polygon

by explorer (Chaplain)
on Jul 24, 2006 at 10:39 UTC ( #563231=note: print w/ replies, xml ) Need Help??


in reply to Re^2: Speeding up point-in-polygon
in thread Speeding up point-in-polygon

If you can reduce the data to cartesian coords. and the entire zone can reside into RAM, PDL is the faster solution.

Example: If $zone is a piddle of bytes with an 1 where the point's coords, you can retrieve the coords of points into polygon's box limits with:

$area = $zone->slice("$xmin:$xmax,$ymin:$ymax"); $coord_points = wichND( $area );
Now, you will have the coords of all points into the $area:
@x_coords = list $coord_points->slice("(0),:"); @y_coords = list $coord_points->slice("(1),:");
This is the fast clipping method if you can reduce the data universe to cartesian coords.

And PDL is a C compiled library.


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