One of the most powerful features of BGL is that everything is based on a world coordinate system that is spherical and very much like latitude/longitude. Unlike other 3-D graphics systems that are rectilinear systems that overlay a square grid over a map that is really a portion of a sphere, the position of scenery in BGL is specified in world coordinates. The following table includes the elements of the world coordinate system used by BGL and Flight Simulator to specify position in the world.
| Dimension | Variable | Representation |
| Longitude | 48-bit pseudodegrees | 0 at 0° longitude. East is positive; west is negative with overflow wrap at 180°. |
| Altitude | 48-bit iiii.ff signed meters | 0 at sea level. Positive is up; negative is down. |
| Latitude | 48-bit iiii.ff signed meters | 0 at equator. Positive is north; negative is south. |
Note: Although the position of objects on the earth is specified in the world coordinate system, actual design work is done in smaller rectilinear coordinate systems placed with their centers at a given world coordinate. For more information on this technique, see the topic The Object Coordinate System.
The topic Pseudodegrees Used in BGL explains the 48-bit pseudodegrees numbering system and its advantages.