I'm not sure if this is what you are doing, but I have done something similar I think.
When I want to use the centroid geometry of a polygon, what I do is load the layer into postgis, create a new geometry field called "points_geom" or something like that, and write a stand alone program to find the centroid of each feature, adn insert that geometry into the new geometry field. I usually use Java since it has a really nice PostGIS object library Hope this helps -Adam On Thu, May 28, 2009 at 11:01 AM, Varun saraf <[email protected]> wrote: > Hi, > > I know mapserver uses a point-in-polygon method to find a feature > given a set of co-ordinates, but can it do the same thing reversed? > For example. Each polygon I draw has a number associated with it which > is in a "dbf" file with the same name as the "shp" file that mapserver > uses to draw the polygons. My current map file allows me to fetch that > unique number whenever I pass the co-ordinates of any point inside > that polygon (mapserver uses the point-in-polygon method to fetch me > the polygonID). The query I use is > > > http://127.0.0.1:8123/cgi-bin/mapserv.exe?&map=C:/ms4w/apps/workshop-5.0/testMap.map&mode=query&mapxy=-77.098617 > 38.87795 > > where mapxy keeps changing based on the user's click. The html > template I send just has the variable name [polygonID] which helps me > get the polygon ID of the point I specify in the mapxy variable. Now, > is there a way in which I can send this polygonID to mapserver and get > hold of any point (perhaps the centroid) inside of this polygon? Can > someone point me in the right direction here? > > Thanks a lot. > > -Varun > _______________________________________________ > mapserver-users mailing list > [email protected] > http://lists.osgeo.org/mailman/listinfo/mapserver-users >
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