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3d Helmert 7 Parameter Transformation

Question asked by CADEngr2014 on Aug 2, 2019
Latest reply on Aug 16, 2019 by MKennedy-esristaff



I am using ArcMap 10.4.1.

My question does not pertain directly to ArcMap, but to an excel 3d similarity transformation calculator I am attempting to develop.  I am using a decent text reference (Datums and Map Projections, by JC Iliffe) that gives me 4 of the matrix (vector) relationships but, beyond setting the provisional values to zero as a first approximation, I am unclear what additional assumptions are being made to solve all the variables such as rotations about each axis, lambda, etc..  My example is not a 3d Helmert 7 parameter type, which I would actually prefer.  So I have to ask, does anyone have a 3d Helmert 7 parameter transformation example that has a little more detail beyond the first assumption to assist in solving?