On Thu, 1 Feb 2007, George Patterson wrote: > The interpolation should also take into account the distance between the > METAR stations and the plane and weight the effect of the weather > effects from there. > > Example: If I am flying right above a METAR station and there is another > one 100km away, then ignore the distant station.
Well it is ignored already of course. ;) At the moment, only the nearest METAR is used. The other idea (other than time interpolation) is to compute some sort of weighed average between METAR stations around the aircraft depending on the distance to them. Time interpolation is necessary too anyway, to smoothen out a METAR update from the one and same station, and also for transients emanating from switching the set of stations being used as lined out above. I would expect these changes to be fairly small under normal circumstances (although a front can pass a station and shift the wind quite dramatically)-- but it's still transients and can stir up autopilots. But I think I have ran into a bug too: Using --enable-real-weather-fetch does not set /environment/weather-scenario to "METAR" automatically. The environment code checks that property here and there, so I guess it matters. METAR is not an optimal source for weather data, but perhaps the best we can get for now (without paying big money for it). There are no METAR stations out in the oceans for instance. And all METAR stations does not provide the same set of information either. An alternative to using METAR could be designing some sort of weather generator server that provides a realistic (not real) weather which, contrary to METAR, has complete data for the whole world. I have something now which is a fair bit better than it was before: notoriously barrel rolling the pa24-250 on a METAR switch has been replaced by a mere shake. (I have yet to figure out what @$&*%! piece of code is bypassing my nice and smooth interpolation of /environment/pressure-sea-level-inhg all the time.) ------------------------------------------------------------------------- Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier. Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel