RE: [OpenMap Users] Speeding Up isPointInPolygon

From: Sutphin, William B CIV NUWC NWPT <william.sutphin_at_navy.mil>
Date: Wed, 2 Jun 2010 15:24:41 -0400

Thanks

Creating the BoundingCirle would have to be done every iteration of the simulation, correct? Because the location of the polygon moves as the sim progresses.

Do you mean by "bunch of polys" multiple polygons composing a single check? I have a single polygon for each track, and lots of independent tracks moving over a bunch of victims.


Bill Sutphin
Naval Undersea Warfare Center, Division Newport
Bldg 1351, Room 211C
Newport, RI 02841
(401) 832-5813
DSN 432-5813

 

> -----Original Message-----
> From: Don Dietrick [mailto:dfdietrick_at_gmail.com]
> Sent: Wednesday, June 02, 2010 7:59
> To: Sutphin, William B CIV NUWC NWPT
> Cc: openmap-users_at_bbn.com
> Subject: Re: [OpenMap Users] Speeding Up isPointInPolygon
>
> Hi Bill,
>
> Are you doing a BoundingCircle check before calling isPointInPoly?
> You can create a BoundingCircle that encapsulates the poly,
> and then call BoundingCircle.intersects(pnt, 0) on that
> representative BoundingCircle.
>
> If you have a bunch of polys, you can load them into a
> ExtentIndex (there's an ExtentIndexImpl) that will do the
> testing for you, and it does filtering on the front end to
> save the expensive checks for later.
>
> All of these classes are in the geo package.
>
> Hope this helps,
>
> Don
>
> On Wed, Jun 2, 2010 at 7:25 AM, Sutphin, William B CIV NUWC
> NWPT <william.sutphin_at_navy.mil> wrote:
> > Hi
> >
> > I am doing a simulation that builds a beam pattern as a
> shape, moves the beam pattern around the surface and counts
> things inside.  The beam pattern is usually a "V" shape
> (depending on the horizontal beam width angle) and five
> degree segments that make the closing arc.  Profiling the
> application shows a lot of time spent figuring out if things
> are inside the polygon or not.
> >
> > Is there anyway I can speed this up?  I'm open to all ideas
> including accepting a little less accuracy in the "is inside"
> detections.  Also am not adverse to hacking the method to
> pass in more reusable objects.  A lot of things tend to be
> way out of the shape, so some early detection ideas might be
> good to avoid isPointInPolygon altogether.
> >
> > Thanks
> >
> > Bill Sutphin
> >
> >
>

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Received on Wed Jun 02 2010 - 15:34:04 EDT