Thanks Andrea for the links. Yes, I think the problem is similar, in fact I was also looking for concave hull and alpha shapes algoithms, but the only open solution I've found is from CGAL [1] and... it's too complex to extract and reimplement in my context (database procedural programming).
IWe have implemented something very "rude": 1 - logically aggregate polyongs in clusters (given a certain distance) 2 - buffer each polygon mantaining the shape (not the usual buffer, which make rounded artifacts) 3 - geometrical union 4 - shrink the result (unbuffer) But I have the time for a long holiday waiting the end of the process :) [1] http://www.cgal.org/Manual/last/doc_html/cgal_manual/Alpha_shapes_2/Chapter_main.html 2010/5/6 Andrea Aime <[email protected]>: > G. Allegri ha scritto: >> >> I'm looking for an algorithm to do polygon cluster aggregation, >> similar to the ArcInfo "Aggregate Polygon" [1]. >> I know about GEOS "Cascaded Union", but I need two more features: >> >> 1 - clustering of polygons that fall within a a certain threshold >> distance from each other >> 2 - mantain orthogonality, i.e. the original angles/shapes > > I don't know of any such implementation, but it looks somewhat > similar to the computation of a concave hull: > > http://ubicomp.algoritmi.uminho.pt/local/concavehull.html > http://stackoverflow.com/questions/83593/is-there-an-efficient-algorithm-to-generate-a-2d-concave-hull > > Cheers > Andrea > > -- > Andrea Aime > OpenGeo - http://opengeo.org > Expert service straight from the developers. > _______________________________________________ > Discuss mailing list > [email protected] > http://lists.osgeo.org/mailman/listinfo/discuss > _______________________________________________ Discuss mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/discuss
