Hey all, There are quite a few devs working with OpenStreetMap data in 3d and judging from screenshots, they've been able to do some pretty awesome stuff so far. I'm trying to do something similar and wanted some feedback, specifically for rendering area data, that is, anything that falls under the 'area' primitive in terms of OpenStreetMap data -- buildings, borders, etc. I'm particularly interested in how to convert area/relation information from *.osm xml data into polygons that can be rendered (decomposed into triangles).
Starting from the osm area primitive info [1], it's possible to get contours (ie node lists) for outer geometry and holes within the area. This data can then be fed into something like poly2tri [2], which is a lib that will triangulate simple polygons (holes can be specified too). The triangulated data is a mesh that can be fed into any renderer, like OpenGL. However, we can't assume all area data are simple polys; [4] shows some building geometry that's not strictly simple. So my main problem/question to devs that are rendering buildings/area geometry in 3d is: * How do you build the 3d geometry for areas that are potentially complex polygons? [1] http://wiki.openstreetmap.org/wiki/Relation:multipolygon#Usage [2] http://code.google.com/p/poly2tri/ [3] http://i.stack.imgur.com/W8Uym.png Regards, Preet _______________________________________________ dev mailing list [email protected] http://lists.openstreetmap.org/listinfo/dev
