[Gdal-dev] share the common edge of nearby polygon?

[Markus Neteler]

On Fri, Jan 23, 2004 at 04:44:48AM -0500, Christoph Spoerri wrote:
> What you are looking for is a vector format with topology. The one format I 
> know of is the ArcINFO/coverage format. Yet, when using the OGR the topology 
> information is lost, since it does not expose the topology of the underlaying 
> data. But, Frank W. may have more info on this.
> 
> You may want to look at the GEOS library, which has some support for topology 
> (http://geos.refractions.net/).
> 
> Christoph

Another option is GRASS GIS (Free Software, take a look at GRASS 5.7!):

http://grass.itc.it

[ It were nice to have Douglas-Peucker implemented directly.]

Markus

> 
> On Sunday 25 January 2004 04:29 am, Fu Chen wrote:
> > Hi!
> >
> > I try to use Douglas-Peucker approximation algorithm to simplify the
> > polygon in the GIS datasets. But it won't be useful on the common shp
> > file for by ogr it get the points of the whole polygon. I can't know
> > where is the common edge of nearby polygon. If use DP algorithm on every
> > polygon itself, the common edge will not fit together.I need to put DP
> > algorithm on the common edge seperately.
> >
> > So I hope the dataset of GIS should have the information of the common
> > edge, and the polygon built by refering to common edges. This will save
> > the store space (will not store the same point twice) and be easy to
> > simply the line.
> >
> > any GIS format take this design? Any software to translate shp file to
> > that format?
> >
> > Thank you!
> >