[postgis-users] Creating a simple polygon encompassing a given number of points

Nicolas Ribot nicolas.ribot at gmail.com
Mon Sep 10 11:46:37 PDT 2012


You could use st_convexHull on the point set and then buffer it with st_buffer.
(st_concaveHull may give you better results on polygon approximation
(see: http://postgis.refractions.net/documentation/manual-2.0/ST_ConcaveHull.html)


On 10 September 2012 20:39, René Fournier <m5 at renefournier.com> wrote:
> I've written a script to migrate location data from MySQL to PostGIS.
> Each region contains 5-20 locations. I would like my script to create a simple polygon for each region that encompasses its locations (lat/lng points). I say simple in the sense of not too many vertices (< 10), even if the region contains 20 points.(The easiest thing would be a bounding box, but I would like it a bit more defined than that.)  Additionally, I would like the polygon to be a bit bigger (say, by 10 meters) than the points it contains.
> Just wondering if this is something that can be done in a PostGIS query or PHP using some algorithm for simple. What would you recommend? Thanks!
> ...Rene
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