[postgis-users] User Friendly vs Explicit

[Norman Vine]

Mark Fenbers writes:

Our weather radars are essentially randomly spaced from each other.  The effective range of the data gleaned from the radars is 125
km.  Fortunately, the radars are usually closer than 250 km to each other in the eastern half of the United States such that there
are few, if any, "holes" with no radar coverage.  What I'm looking to do is just a simple concept.  Two adjacent radars which
overlap will have a bisecting line between them such that the line represents equal distances from one radar or the other.  Doing
this with several surrounding radars, we can come up  with an N-sided polygon around the "base" radar where N is the number of
surrounding radars.  This polygon computed by postGIS represents the region closer to the base radar than any of the other radars.
The vertices of this polygon are the intersections of the bisecting lines between each of the surrounding radars.

This is commonly referred to as the Vornoi Diagram
http://www.cs.cornell.edu/Info/People/chew/Delaunay.html

program that can compute this for you
http://www-2.cs.cmu.edu/~quake/triangle.html

HTH

Norman