[postgis-users] new GEOS goodies in PostGIS CVS

Wood Brent pcreso at pcreso.com
Fri Aug 1 18:32:56 PDT 2003

--- David Blasby <dblasby at refractions.net> wrote:
> I wrote a GEOS geometry -> PostGIS geometry converter. 

I've been using GIS & Postgres for some time, as well as commercial topological
GIS packages. It looks to me as if Postgres/PostGIS/GEOS/GRASS are getting
close to a point where the commercial packages can be superceded....

> I also added these GEOS functions:
> intersection(geometry,geometry)
> buffer(geometry,float8)
> convexhull(geometry)
> difference(geometry,geometry)
> boundary(geometry)
> symdifference(geometry,geometry)
> GeomUnion(geometry,geometry)
> "Union" is an SQL reserved word, so I used "GeomUnion" - anyone have a 
> better name?

merge or combine? (Join is also appropriate but can be misconstrued in a
relatiional environment)

> * convexHull() isnt working (should work when Yuri commits)
> * buffer() -- has known issues (Yuri is looking at it)
> * empty geometries are converted to SQL NULL's.
> * GEOS is still leaking like a sieve - I'll make it stop when
>    Yuri commits his memory management update

Thanks for the update. I'm paticularly interested in this as the data
management tool behind GRASS, the various packages are coming together pretty effectively.

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