Partially-conformal variations of the Standard Molodensky datum transformation

Standard Molodensky is a recognised method of transforming coordinates between geodetic datums. Although less accurate than some other methods, it has the merit being direct. That to say can be applied coordinates, without involving Cartesian that give rise difficulties in computing latitude. This paper considers use when at least one datums 2D+1D nature, meaning horizontal and vertical positions are obtained by different methods. was generally case before 3D positioning satellites widespread characteristic local still used. The property weakens argument for conformality, invites possibility translation parameters might used shifts. including Z-rotation as 7th parameter also considered. Besides ideal those who favour simplicity Molodensky, variations introduced this offer significant improvements accuracy such error reductions 75%, 69% 99% three selected studies.