Spectra Precision Survey Pro v4.5 Ranger User Manual User Manual
Page 216
User’s Manual – GPS Mode
206
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
ground
/(R+h) = dist
elip
/R
dist
elip
/dist
ground
= R/(R+h)
k
elip
= R/ (R+h)
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
= k
elip
* k
map
dist
grid
= dist
ground
* k
cf
Fig. 5: Ellipsoid Scale Factor
The effect of height above the ellipsoid on scale.
R+h
Radius of
Ellipsoid, R
Ellipsoid
Height, h
Distance on
Ground
Distance on
Ellipsoid