Ben wrote: > I have some 3D polygonal data in 3D shapefiles that I need > to process in GRASS and then export to VTK for interactive > exploration. > The data represents what archaeologists call "profiles", > i.e. vertical cross-sections through the soil that document > soil layers. > > I think the term "catena" exists in some geosciences for > roughly the same thing. The data is synthetic, i.e. > digitized from idealized hand-drawings done in the field. > As such, it has no actual W-E or N-S extent, only top to > bottom. > > I realized that v.in.ogr cannot import such data. Even > though it reads the 3D coordinates just fine, it treats the > topology as 2D, trying to calculate X-Y areas and finding > labeling points to attach the attributes. > Which fails of course, as no 2D centroid can be calculated > for a 3D area that has no extent in the X-Y plane!
.... you could always relabel the axes ... GRASS won't know what it thinks is x-y is really x-z or x-time. You can then swap it back once in VTK. > So I went on to patch v.in.ogr to import 3D lines w/o area > checking and that at least gave me an option to import the > geometries. I then added support for 3D faces which allowed > me to import a better representation. > > But now I am stuck on the attribute side of things: > How do I attach attributes to GV_FACE type geometries? > I suppose it should be equivalent to how it is done for > GV_BOUNDARIES? > But using V_KERNEL instead of V_POINT for attaching the atts? > Does anyone here have any experience with this? > Any other GRASS modules that need to do the same thing so I > could learn from them? v.in.dxf is probably your best bet, but you may have already surpassed what it does. Hamish _______________________________________________ grass-dev mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-dev
