Curt Olson writes: >D Luff writes: >> Yes, that's basically what I'm planning to do. I keep forgetting >> you're a driving sim guy and probably have some very relevant >> expertise here. What co-ordinate systems are you using?
>That's not a trivial question to answer, why don't I say we are using >the MN state plane coordinate system which maps into X, Y, Z with Z >being up, X being in the longitude direction, and Y being in the >latitude direction. I'm rapidly coming to the conclusion that nothing about coordinate systems is ever trivial :-) >> At airport level lat/lon spherical co-ordinates are really overkill >> for whats basically a planar problem. I was considering assuming >> that for a limited area (a few miles each way) one could assume that >> lines of lat and lon were straight and parallel, and possibly map >> the lat/lon to x/y depending on latitude to get the x and y axis >> subdivisions equal. >> This would be a lot cheaper that doing proper spherical -> planar >> projection. The logical network would be defined in terms of these >> x,y and the airplanes lat/lon quickly and cheaply converted. >> Comments? >For doing 2d positions near the airport that might be ok, but when you >calculate which heading you want to travel to go from point A to point >B, you might be a fair bit off if you don't use spherical or wgs-84 >coordinates. This could result in the autonomous airport traffic >taxing off the edge of a long taxiway, or getting pushed off the edge >of a long runway, or doing other odd stuff. I think that should be OK, since the end points of all the long runs will be defined in the logical network in x,y, and they will have been converted in the same manner as the plane is, so it should hit them spot on. I'm just a touch worried that it will appear to describe an arc down the runway though as it gets converted to WGS84 in my simple scheme for rendering. Still, if it doesn't work I can always use a full conversion to WGS84 for both the network and planes. Cheers - Dave _______________________________________________ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
