You need to calculate a distance between base center coordinates and object coordinates you want to place in the base, and bearing from base center to the object. For runways you will need to get the END1 and END2 coordinates, and not the coordinates of midpoint of runway.
If you have all longitudes and latitudes, you can calculate distances and bearings from formulas that are for example on this page:
http://www.movable-type.co.uk/scripts/latlong.html
And then, the local (in base) coordinates you can get from:
x = distance * cos (bearing)
z = distance * sin (bearing)
Only I'm not sure, whether you need to change the sign of either "x" or "z", or exchange sine with cosine, because I didn't check the results of these formulas recently.
And if you need "y" coordinate (above the ground) for any reason (it's needed for example for runway lights, which aren't mapped to sphere at all):
y = (1 - cos (distance / earth_radius)) * earth_radius
Note that "x", "y", and "z" are in meters, so you need to provide "distance" and "earth_radius" for the formulas in meters too. The calculated "y" is a value you need to subtract from "y" coordinate of END1/END2 objects (other than runways), which aren't mapped to sphere, to make their ends placed on the ground, and not float in air. For longer objects, it's better to subtract less than calculated "y" (but less by the same amount) for both ends, because otherwise the center of END1/END2 object will be underground.
---------- Post added at 02:54 ---------- Previous post was at 02:31 ----------
Has anybody already added the real world airports for Ontario .. all of Canada .. all of U.S. ? ....
I'm not sure for all of Canada, but you can check runways exported by Topper
in this thread. There are runways for Europe, U.S. and worldwide.
