1. REDUCTION TO THE ELLIPSOID
Earth Radius
6,372,161 m
20,906,000 ft.
S = D x R
R + h
h = N + H R
S = D x
R + N + H
Earth Center

2. REDUCTION TO GRID Sg = S (Geodetic Distance) x k (Grid Scale Factor)
Sg = x
= meters

3. REDUCTION TO ELLIPSOID
S = D x [R / (R + h)]
D = meters (Measured Horizontal Distance)
R = 6,372,162 meters (Mean Radius of the Earth)
h = H + N (H = 158 m, N = - 24 m)
= 134 meters (Ellipsoidal Height)
S = [6,372,162 / 6,372, ]
S = x
S = meters

4. COMBINED FACTOR CF = Ellipsoidal Reduction x Grid Scale Factor (k)=
CF x D = Sg
x = meters