On Jan 25, 2011, at 1:13 PM, Curtis Olson wrote: > Quick explanation: the world is curved (oblate spheroid) so if in order to > have an ocean that measures zero MSL at all points, it would have to be > curved. To do this perfectly requires a *lot* of polygons. We have been > using large polygons for the ocean so that leads to some errors depending on > where you are within the polygon. Near the verticies will be pretty > accurate, near the middle could be off by a few meters. > > Regards, > > Curt. >
I don't know how big the tiles are, but I ran a ground vehicle due west from the Golden Gate Bridge to see what the variation was. It may just be that the first tile is out of whack? From terrain edge out to 21 miles it goes down and back up. From 21.2 miles out to 100 miles it's totally flat. Ocean surface as compared to 0 MSL : Golden Gate Bridge : 0 Terrain edge/Ocean start/End of channel : 0 Nimitz : -7m MSL 17 Miles out : -7m MSL 21.1 miles out : -3.7 MSL - At vertical wall, assuming Tile edge 21.2 miles out : 0 MSL - Up on new tile(?) 70 miles out : 0 MSL 100 miles out : 0 MSL Screenshots of locations with lat/lon: http://s512.photobucket.com/albums/t325/barefootr/Flightgear/Sea%20Level%20West%20from%20SFO/ Peter ------------------------------------------------------------------------------ Special Offer-- Download ArcSight Logger for FREE (a $49 USD value)! Finally, a world-class log management solution at an even better price-free! Download using promo code Free_Logger_4_Dev2Dev. Offer expires February 28th, so secure your free ArcSight Logger TODAY! http://p.sf.net/sfu/arcsight-sfd2d _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
