[geos-devel] troubles understanding GEOS

[Tobias Nothdurft]

Hi Carlos.

Thanks for your quick response.

I think a code example would be very helpful.

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.

Or am I off the track?

Tobias


Zitat von "Del Cacho, Carlos (Carlos)" <delcacho at lucent.com>:

> Yes, GEOS can do this. There is a spatial index that you can use instead of
> looping all your line strings.
> 
> http://geos.refractions.net/ro/doxygen_docs/html/classgeos_1_1index_1_1quadt
> ree_1_1Quadtree.html
> 
> I am using this structure for a CAD mock up project of mine. I can provide
> example code if you wish, just drop me an email. Basically, you assign any
> piece of data to an envelope, store it in the index, and you can have
> efficient queries afterwards. 
> 
> For reference:
> 
> http://en.wikipedia.org/wiki/Quadtree
> 
> 
> Greets,
> Carlos del Cacho
> 
> 
> -----Original Message-----
> From: geos-devel-bounces at geos.refractions.net
> [mailto:geos-devel-bounces at geos.refractions.net]On Behalf Of Tobias
> Nothdurft
> Sent: martes, 28 de noviembre de 2006 9:44
> To: geos-devel at geos.refractions.net
> Subject: [geos-devel] troubles understanding GEOS
> 
> 
> Hello Guys.
> 
> I've found youre project a few days ago and i'm trying to find out, whether
> i
> can solve my following problem:
> 
> I have to insert a lot of obstacles (Line-Strings) into a map. Afterwards i
> want
> to know the obstacles, which are in a specific section of the map.
> 
> Is this possible using GEOS?
> Do i have to compare my square for a specific section of the map with all
> database-objects to find the obstacles intersecting my square?
> 
> With kind regards.
> 
> Tobias