There is a very nice algorithm in Preparata and Shamos ("Computational
Geometry"). I, for one, would love to have a PDL::PlanarGeometry package
built, to treat 2xN PDLs as collections of points on the plane. Nice
algorithms to start with would include:
- area
- hull
- Voronoi
- delaunay
- polygon union
- polygon intersection
- polygon clean
On May 2, 2012, at 12:33 PM, Steven Lembark wrote:
>
> The nice people at Oracle implement all of their OpenGIS
> "contained within" geometry operators using bounding boxes
> only. This makes it impossible to select non-rectangular
> areas from a map.
>
> Google has gotten me nowhere looking for a PDL geometric
> operator library that (ideally) works on OpenGIS format
> data (WKB, WKT) or at least implements a "contains"
> operator suitable for a point and polygon.
>
> I am not trying to plot anything, just get a boolean
> outcome for, say, which state contains a given lat+long
> or which hospital is closesest to a given point.
>
> Checking CPAN for PDL+GIS gives me PDL::GIS::Proj, which
> isn't about GIS and is also pretty much dead.
>
> Q: Any suggestions for an implemention for selecting
> which of a (largeish) list of polygons contain a
> given point?
>
> thanks
>
> --
> Steven Lembark 3646 Flora Pl
> Workhorse Computing St Louis, MO 63110
> [email protected] +1 888 359 3508
>
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