Direct projection : an efficient approach foe datum transformation of plane co-ordinates
Engberg, Lars E. and Mikael Lilje
Lantmmteriet has decided that SWEREF 99 shall be the Swedish official reference frame and replace RT 90 for surveying and mapping purposes. Transformation between global and local reference frames often leads to lengthy computations involving several consecutive transformation steps. The concept of the direct projection is to project the geodetic (global) system directly to the local system. The result is very good; the residuals are normally around 5 centimetres when local systems are transformed and a few more centimetres for the national system RT 90. Comparisons between direct projection and 7-parameter transformation show that it could be used especially when only 2D-position (map-data) is to be transformed.
Event: XXIII International FIG Congress : Shaping the change
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