[postgis-users] Convex hull without overlapping geometries

[Roald de Wit]

Well, to answer my own question: just create a convex hull for all your
states and then for each of them, difference them with the original
states.
It works (although the query took > 1000s)!
If there are better alternatives, please let me know.

Roald

On Fri, 2008-10-17 at 11:32 +1030, Roald de Wit wrote:
> Hi list,
> 
> To create a simple set of simplified polygons (states of Australia) to
> use for spatial searches from a web client, i'd like to use the
> convexhull function in such a way that the convexhull is not applied
> where the boundaries would overlap with other polygons.
> In short: where the state boundaries are on land: keep everything the
> same, where the boundary hits the ocean: perform a convexhull.
> 
> Is that possible in PostGIS?
> 
> Regards, Roald
> 
> --
> Roald de Wit
> Software Engineer
> roald.dewit at lisasoft.com
> 
> Commercial Support for Open Source GIS Software
> http://lisasoft.com/LISAsoft/SupportedProducts/
> 
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-- 
Roald de Wit
Software Engineer
roald.dewit at lisasoft.com

Commercial Support for Open Source GIS Software
http://lisasoft.com/LISAsoft/SupportedProducts/