EPSG:1040

GNTRANS is a multistage three-dimensional transformation approach. Starting with a conventional seven-parameter transformation, the next stage functionally models the residuals at identical points using a unique, continuous spline surface. The final stage is a stochastic prediction to describe remaining discrepancies. For application and to improve performance, topocentric coordinate offsets are interpolated from a regular grid derived from the above transformation to determine coordinates of an arbitrary input point in the target system and vice-versa.