[geos-devel] troubles understanding GEOS

[Tobias Nothdurft]

Hi, Markus.

> > 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.

But which parts do i have to use, if I want to use the quadtree-functionality of
GEOS in my programm? Only GEOS itself or PostGIS and PostgreSQL to? Do i have to
set up a database myself first or does GEOS this job for my?

Sorry for this many questions ...

Tobias