On Monday 07 January 2008 22:28, Curtis Olson wrote: > On Jan 7, 2008 3:51 PM, Frederic Bouvier <> wrote: > > If we keep the same triangle budget for every tile, we will > > have sparse data and > > features at the equator and much more than what is really > > needed at the poles, > > just because the area covered by each tile will vary greatly ( > > proportional to > > 1/cos( lat ) if my math is ok ) > > My gut feeling is that once you get up (or down) into the > latittudes where the tiles get significantly skinny, the > resolution of the available data drops of significantly. We > really don't have a per-tile triangle budget anyway. The only > place where I see this making a difference is the concentration > of terrain elevation points would increase, but this is up in an > area where we only have very low res terrain data anyway. SRTM > drops out beyond +/- 60 degrees latitude. > > Regards, > > Curt.
Yup - I downloaded lots of SRTM data to play with in GRASS and above/below +/- 60 lat it isn't there. There doesn't seem to be any alternative source of suitable data either so I don't see how FG can cover the poles. (the reason I was looking was because I was interested in the Mt Erebus volcano - FG is quite good for looking at volcanos and other large scale geological features from the air - at some point I'll get together a list of volcanos and astroblemes for the 'places to fly' section of the FG docs/wiki) LeeE ------------------------------------------------------------------------- Check out the new SourceForge.net Marketplace. It's the best place to buy or sell services for just about anything Open Source. http://ad.doubleclick.net/clk;164216239;13503038;w?http://sf.net/marketplace _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
