[geos-devel] troubles understanding GEOS

[Markus Schaber]

Hi, Tobias,

Tobias Nothdurft wrote:

> I also have a tough time realizing the interaction between GEOS and PostGIS. I
> know that PostGIS extends PostgreSQL with geometric functions. But i don't
> understand how my programm can access a PostGIS-extended database with GEOS.

The relation between PostGIS and GEOS is that PostGIS uses GEOS under
the hood to implement some of the geometric functions it provides for
PostgreSQL.

For projection and coordinate systems, PostGIS relies on the proj4
library, and for complex geometric operations (intersection etc.) it
relies on GEOS, instead of re-implementing the wheel.

HTH,
Markus
-- 
Markus Schaber | Logical Tracking&Tracing International AG
Dipl. Inf.     | Software Development GIS

Fight against software patents in Europe! www.ffii.org
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