8. October 1998
co-ordinates are not planar
Geographic co-ordinates are based on a specific reference
system (e.g. sphere or ellipsoid).
Geographic co-ordinates define the perpendicular direction on the
surface of the reference system.
Geographic co-ordinates are ambiguous!
Geographic co-ordinates may define different points on the earth's
surface. This depends on their reference system (the geodetic datum
point on the earth's surface may have many geographic co-
ordinates, depending on their reference system (geodetic
Changing geographic co- ordinates means:
Conversion from the curved surface to a
Geodetic Datum Transformation
geographic co- ordinates between different reference systems or
Terminology confusion with geographic
3 types of co-ordinates define different
perpendicular, based on the gravity
perpendicular, based on the reference surface, specifically
ellipsoid, used for large and medium scale mapping, and in
perpendicular, based on the reference surface, typically
spheres, used for small scale mapping