James Turner wrote: > I think part of the problem is that you (Martin) have looked at this > too much, and the rest of us (except Curt) not so much. Can you > explain for people like me the pipeline you propose to assemble the > data (i.e what pieces of the final result come from what source, and > how), and how that would fit together at runtime?
To the current state we have a coastline around each 'isolated' continent or island which is either made from a single closed polygon (which could be GSHHS) or from the outline around a couple of adjacent polygons (VMap0 political boundaries). To get an overview, please check here: http://wiki.osgeo.org/wiki/Geodata_Repository#PostGIS_serving_vector_data This coastline is the basic factor for a simple principle: Everything inside this coastline is counted as ground, the entire area outside the coastline is "Ocean". The same principle applies to lakes - just in the reverse order: Everything inside the lake shoreline is water. So, even if our STRM elevation grid would indicate some sort of elevated ground outside our coastline, it's going to get clipped out due to the given principle. In contrast, if there's no elevation data for an area inside the coastline, then the ground is still going to get extended in accordance with the coastline .... but at sea level. There's a nice example for these corner cases if you approach RWY 24 at TNCE in the 1.0.1 Scenery. I'm proposing a similar but somehow opposing schema (talking is cheap ;-) Let us have the seabed modelled using bathymetry data, clipped against the same coastline which we're using to clip the ground elevation, limit the maximum 'elevation' of the seabed to the elevation of the respective coastline, which is presumably at MSL for all ocean shorelines - or the individual elevation of the respective lake. Probably limit the seabed elevation to a few centimetres below to allow for some nice waves .... I don't see any reason why and how this approach would set KSFO under water. > Also, is global (even crude) coastal bathymetry data available? Yes, I even had a copy of global bathymetry data on my local disk few years ago, but lost it due to sort of a crash (well, the data is still sitting there, but I have to re-assemble the partitions before I'm able to read it). Cheers, Martin. -- Unix _IS_ user friendly - it's just selective about who its friends are ! -------------------------------------------------------------------------- ------------------------------------------------------------------------------ This SF.net email is sponsored by: SourcForge Community SourceForge wants to tell your story. http://p.sf.net/sfu/sf-spreadtheword _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
