Re: testing if a point is inside a polygon
- To: mathgroup at smc.vnet.net
- Subject: [mg96429] Re: testing if a point is inside a polygon
- From: mark mcclure <mcmcclur at unca.edu>
- Date: Fri, 13 Feb 2009 03:45:02 -0500 (EST)
- References: <gmp0mt$btn$1@smc.vnet.net>
On Feb 9, 5:31 am, Mitch Murphy <mi... at lemma.ca> wrote: > is there a way to test whether a point is inside apolygon? ie. > PointInsidePolygonQ[point_,polygon_] -> True or False Of course, we can write our own program to do just about anything we want. If you want to know whether there is a built in function "InPolygon", the answer is no. If you want to if there are freely available packages that include this functionality, the answer is yes: CompG: http://library.wolfram.com/infocenter/MathSource/5712/ and IMTEK: http://www.imtek.de/simulation//mathematica/IMSweb/ Curiously, the functionality is clearly "in Mathematica", it's just not exposed. You can see that a point in polygon is implemented by playing with the following: Graphics[Tooltip[Polygon[ {{0, 0}, {2, 0}, {2, 1}, {1, 1}, {1, 2}, {0, 2}}], "in polygon"]] In fact, there must be a large computational geometry library contained in the Mathematica kernel to support the extensive graphics routines. Hopefully, that functionality will be exposed in the not too distant future. Mark McClure