[postgis-users] How to generalize or simplify a Polygon

[Christoph Spoerri]

I'm not sure if this was mentioned before, but earlier this summer their was a 
post on the list by somebody that implemented the D-P algorithm on lines as 
an extension/function to PostGIS. This may be a good starting point to also 
simplify polygons (if required).

Along this line, I was also think if it would be possible/useful to store the 
simplified feature within the database. This would then allow the user to 
specify which 'version' of a spatial dataset should be retrieved. This would 
provide a similar functionality as is already available for raster datasets 
where pyramids are used to provide this functionality. What does the rest of 
you think about this?

Christoph


On Thursday 28 August 2003 04:29 pm, Martin Davis wrote:
> > of self-intersection when you process a polygon. So why not put it in as
> > an method that is only a member of LineString / MultiLineString class ?
>
> If we were putting D-P into JTS, that would be one place to put it,
> alright.  However, as I said I'd really rather keep JTS focussed on core
> algorithms.
>
> On a philosophical note, adding algorithms as methods to Geometry objects
> seems to be encouraged by the OO paradigm, but it's not the most scalable
> or flexible way of doing things.  For algorithms such as D-P which are
> pretty independent of the internal representation of the Geometry I think
> it's nicer to keep them outside the Geometry class in a separate algorithm
> class.
>
> Martin Davis, Senior Technical Architect
> Vivid Solutions Inc.
> Suite #1A-2328 Government Street   Victoria, B.C.   V8T 5G5
> Phone: (250) 385 6040    Fax: (250) 385 6046
> EMail: mbdavis at vividsolutions.com  Web: www.vividsolutions.com
>