On Mon, Jun 21, 2010 at 09:13:16AM -0700, Martin Davis wrote: > strk, > > The JTS Developer's Guide is a bit confusing. The geometry given in the > example is NOT the geometry depicted in the illustration. (This is a > doc bug - but I"m not sure if and when I can fix it). > > When I run the geometry below in JTS I get: > > Polygons: > GEOMETRYCOLLECTION ( > POLYGON ((189 98, 83 187, 185 221, 325 168, 189 98)), > POLYGON ((185 221, 88 275, 180 316, 292 281, 185 221))) > > Dangles: > MULTILINESTRING ((185 221, 100 100), > (0 0, 10 10)) > > I believe this is the expected result.
Uhm, that's w/out self-noding, right ? --strk; > > Hope that helps > > Martin > > strk wrote: > >Martin, I'm adding a testcase for the Polygonizer using example from : > >"JTS Developer's Guide, Chapter 6 - Polygonization" > > > >Here's the input, represented as a collection: > > > >GEOMETRYCOLLECTION( > > LINESTRING(0 0, 10 10), > > LINESTRING(185 221, 100 100), > > LINESTRING(185 221, 88 275, 180 316), > > LINESTRING(185 221, 292 281, 180 316), > > LINESTRING(189 98, 83 187, 185 221), > > LINESTRING(189 98, 325 168, 185 221)) > >) > > > >When passing it into the Polygonizer class I get > >2 rings, no cut or invalid edges and 3 dangles. > >Also notable is that of the 3 dangles, 2 are identical > >and specificall are the isolated edge (first geometry > >in the collection). > > > >The example in the guide suggests the rings should > >be 3 instead, and that there should be one cut > >edge (represented in blue) and 2 dangles > >the red ones. > > > >Does it sound as a bug in GEOS or does JTS give the > >same results ? > > > >Note that forcing proper noding using the union trick > >does give the 3 expected rings, but still lacks the > >cut edge and duplicates the dangle. > > > >Thanks in advance. > > > >--strk; > > > > () Free GIS & Flash consultant/developer > > /\ http://strk.keybit.net/services.html > > > > -- > Martin Davis > Senior Technical Architect > Refractions Research, Inc. > (250) 383-3022 -- () Free GIS & Flash consultant/developer /\ http://strk.keybit.net/services.html _______________________________________________ geos-devel mailing list geos-devel@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/geos-devel