METHOD AND APPARATUS FOR COORDINATE SYSTEM CONVERSIONS

摘要

A method for converting between source coordinates in a source coordinate system and target coordinates in a target coordinate system includes the step of defining a coordinate system conversion tree extending from a root coordinate system and branching to a plurality of other coordinate systems including the source and target coordinate systems do that the source and target coordinate systems are connected to a common coordinate system other than the root coordinate system. Coordinate conversions are performed between the source and target coordinates along braches extending from the source coordinate system to the common coordinate system and to the target coordinate system without returning to the root coordinate system. Contextual sata is associated with the coordinates to permit conversion to an adjacent coordinate system. Since coordinate conversions are performed with respect to a common coordinate system, a distributed framework of coordinate systems is provided for reliably converting coordinates between source and target coordinate systems. New coordinate systems can be readily added to the tree.