Also, just as a note. The locateRecords() method returns a box in box
filter, which will generate incorrect results because some shapes will
have extents that intersect when none of the actual points do. In other
words the filter checks extents to extents, not point in polygon, etc...
. On the other hand, it is an optimized way to filter out "most" of the
shapes that don't intersect. If you have a lot of geometries you can
speed things up by first doing a box in box filter, and then further
filter out those shapes with a more rigorous intersection algorithm.
Martin
-----Original Message-----
From: Hudson Brian R Contr AFRL/IFSF [mailto:Brian.Hudson_at_rl.af.mil]
Sent: Wednesday, August 04, 2004 4:26 PM
To: Ben Podoll; openmap-users_at_bbn.com
Subject: RE: [OpenMap Users] shapefile checking bounds
Hey,
If you have a spatial index file along with the shp file it should be
pretty easy.
You can just use the locateRecords function of the SpatialIndex class.
For an example, take a look at the ShapeLayer.
Brian Hudson
-----Original Message-----
From: owner-openmap-users_at_bbn.com [mailto:owner-openmap-users_at_bbn.com]
On Behalf Of Ben Podoll
Sent: Wednesday, August 04, 2004 5:49 PM
To: openmap-users_at_bbn.com
Cc: 'Don Dietrick'
Subject: [OpenMap Users] shapefile checking bounds
My problem is fairly complex but somewhat straightforward.
I have a shapefile of National Weather Service warnings and watches.
I want to be able to take the extents that the OpenMap is viewing (i.e.
the 4 lat/lon corners) and check if any /shape/ in the shapefile
intersects. Or in other words is within their viewing area (or at least
a piece of one)?
Is there any good way anyone knows of to do this?
Ben
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Received on Wed Aug 04 2004 - 20:00:25 EDT