Hi Martin, You may already know the benchmark done by Erwan's team with some java implementations (http://conference.osgeo.org/index.php/foss4g/2008/paper/view/282/177) It eventually shows the triangulator I have written a few years ago (available on http://geo.michaelm.free.fr/OpenJUMP/resources/) is very fast (I have to add it is not 100% robust as it sometimes fails for large datasets - more than 100k points) They also wrote a more recent paper about their new implementation for orbisgis : http://hal.archives-ouvertes.fr/docs/00/32/95/03/PDF/CDT-paper.pdf
Now about your question : INPUT - should be able to input ponctual (sites) , lineal (breaklines), polygonal geometries (points and breaklines to be extracted) - collection of coordinates INPUT/OUTPUT - in my plugin, I decided that when the input was a single polygon, the output should be a triangulation containing only triangles inside the polygon (not all triangles inside the convex hull) (may not concern the low level api) OUTPUT - in my Triangulation class, I decided to return a simple Coordinate[] array containing n*3 objects (elements 0, 1 and 2 composing the first triangle...) I'm not that sure, but I think this structure just contained references to input coordinates (memory-friendly) - i would prefer a collection of Linestrings or a collection of Polygons than a MultiLinestring or MultiPolygon, because I'm not sure a mutigeometry of one million elements is easy to deal with (spatial indexation inefficient for example). Moreover, individual geometries can give the oppurtunity to keep the tin structure with links between elements represented as attributes, or to compute height, slope, orientation on every individual triangle and keep them as attributes. I understand why a Tin structure is interesting (no duplicate), but not a multi-geometry. My 2 cents Michaël Martin Davis a écrit : > To those that are interested in the upcoming JTS triangulation API, a > question: > > What type of input and output structures would you find useful? > > Currently I'm developing the following: > > INPUT: > - Geometry (from which the site/vertex coordinates are extracted) > - Collection of Coordinates > > OUTPUT: > - MultiLineString containing triangulation edges > - GeometryCollection of Polygons containing triangles > > You can also work directly with the internal datastructures of the > triangulation (Vertices, QuadEdges, etc), but this requires a higher > level of understanding. > > Is there any other option I haven't though of? > > ------------------------------------------------------------------------------ Register Now & Save for Velocity, the Web Performance & Operations Conference from O'Reilly Media. Velocity features a full day of expert-led, hands-on workshops and two days of sessions from industry leaders in dedicated Performance & Operations tracks. Use code vel09scf and Save an extra 15% before 5/3. http://p.sf.net/sfu/velocityconf _______________________________________________ Jump-pilot-devel mailing list Jump-pilot-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/jump-pilot-devel
