On Thursday 19 March 2009 02:11:21 pm Greg Hawkes wrote: > Hello all, > > FlightGear's "Tower" view at my local airport (Melbourne's Tullamarine, > YMML) is about 300 metres from the actual location of the air traffic > control tower. I would like to change the Tower View's "From" location > to correspond to the actual location of the tower.
This is actually an issue for (many?) other airports as well. Of the 3 airports I have tried, KSFO, KCCR and EHAM, only KSFO appears to have this correct. For KCCR the tower position is off by about 500 meters and for EHAM is looks like it is off by about 50 meters. Like Greg I tried to figure out how to change this and have yet to find an answer. > > I thought I could do this easily by editing the apt.dat.gz file in > FlightGear's ~/Airports/ directory. I gunzip-ed, edited, and gzip-ed the > file, and updated the "14" record for YMML as follows: > 14 -37.669465 144.830636 0 0 ATC Tower > > (These coordinates were obtained from Google Earth.) Like Greg I have Google earth coordinates for the tower at KCCR. If someone knows how to correct this info I would be glad to provide that information. Actually here they are: 37.985817 N 122.055268 W I don't know how high the tower is but the field elevation is listed as 26 feet. > > However, when I run FlightGear the view location of the "Tower" view is > unchanged. When I browse the internal properties, I find the following > values: > /sim/tower/airport-id='YMML' > /sim/tower/altitude-ft='483' > /sim/tower/latitude-deg='-37.66919517' > /sim/tower/longitude-deg='144.8451658' > > Obviously these values do not correspond with those I have inserted into > apt.dat.gz. Where does FlightGear obtain these values? > > The "altitude-ft" parameter is curious. According to this site > http://www.airservicesaustralia.com/aboutus/facilities/towers/melbournetowe >r.asp > > ...the cabin is 120 feet (about 37 metres) above ground. Where does > FlightGear get its "483 feet" value? What is the datum for this number? This is probably height above mean sea level since that is how most altitudes are specified. So if you subtract the field elevation from 483ft you should get something close to 120ft assuming that the 483ft number is close to correct. > > Does FlightGear make use of the apt.dat.gz file to initialise its > airport data? If not, what is this file used for? > > Regards, > Greg Hawkes ------------------------------------------------------------------------------ Apps built with the Adobe(R) Flex(R) framework and Flex Builder(TM) are powering Web 2.0 with engaging, cross-platform capabilities. Quickly and easily build your RIAs with Flex Builder, the Eclipse(TM)based development software that enables intelligent coding and step-through debugging. Download the free 60 day trial. http://p.sf.net/sfu/www-adobe-com _______________________________________________ Flightgear-users mailing list Flightgear-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-users
