Moldensky 3_D coordinate transformation model

name :ahmed wazer                                                                          Nov 2012

category: moldensky transformation formula

Molodensky Transformation Formulas

This transformation can also be done in geodetic, curvilinear coordinates using the Molodensky Transformation equations where

f_WGS84 = f_Local + Df
l_WGS84 = l_Local + Dl
h_WGS84 = h_Local + Dh

where Df, Dl, Dh are provided by the standard Molodensky transformation formulas of

• Df" = {-DX sinf cosl - DY sinf sinl + DZ cosf + Da(R_N e² sinf cosf)/a + Df [R_M(a/b) + R_N(b/a))]
              sinf cosf} [(R_M+h)sin 1"]
• Dl" = [-DX sinl + DY cosl] × [(R_N+h)cosf sin 1"]^-1
• Dh  = DX cosf cosl + DY cosf sinl + DZ sinf - Da(a/R_N) + Df(b/a)

where f, l, h are geodetic coordinates of the point in the local datum.

There are other datum transformation procedures, but these are the big three. Note that when you find a site with the required transformation parameters, the required equations are generally listed also.