On Thursday 15 September 2011 22:08, HB-GRAL wrote: > No, it looks like the mapping with apt.dat data is inaccurate, at least > outside the United States. > > I checked some airports the last days. You can not say that FlightGear > or X-Plane data is accurate and the rest of the mapping world is > missing the "points". It does not depend on aviation or not. A lot of > runways are misplaced, and I am just asking about the reason. Maybe one > of the reasons is that apt.dat is based on old analog imagery, not > available anymore.
I like to think that the positional errors of many (most non US?) aerodromes are due to mistakes made when changing from one datum to another. Errors in runway orientation at unmodifed airfields (with default layouts) appear to be caused by confusion between magnetic and true bearings, with magnetic being used as true. Not a major problem where magnetic variation is low but an error nonetheless. Martin. ------------------------------------------------------------------------------ BlackBerry® DevCon Americas, Oct. 18-20, San Francisco, CA http://p.sf.net/sfu/rim-devcon-copy2 _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
