Tripod Data Systems SURVEY PRO User Manual page 216

User's Manual – GPS Mode
The effect of height above the ellipsoid on scale.
Ellipsoid Scale Factor
This scale factor accounts for the height of the ground above the
reference surface (the ellipsoid). This scale factor is defined
geometrically: Consider the following diagram:
dist
dist
k
elip
Combined Scale Factor
Generally, the two scale factors are multiplied together into a
combined scale factor. The combined scale factor is then applied to
grid distances to get ground distances:
k
cf
dist
206
Distance on
Ground
Ellipsoid
Height, h
Distance on
Ellipsoid
Radius of
Ellipsoid, R
Fig. 5: Ellipsoid Scale Factor
/(R+h) = dist
ground elip
/dist = R/(R+h)
elip ground
= R/ (R+h)
= k * k
elip map
= dist * k
grid ground cf
R+h
/R