Spectra Precision Survey Pro v4.6 Recon and Nomad User Manual - Manual (Page 265)

GPS Coordinates
255
Switching from Grid to Ground
1. Any time a Mapping Plane mode zone or localized site record is
selected, go to the Survey > Projection screen and tap
Setup Ground Coordinates….
2. In the Projection Definition box, select Use Ground
Coordinates
.
3. Select the Ground Coordinate Origin; this is the point
around which the scale factor will be applied. The
recommended procedure is to select or key in a
project location close to the survey area. It is most
important that the origin be close to the height of
the survey area for proper ground scale. You can
also choose to apply the ground scale factor at the
map projection origin with any height scale factor
you wish.
4. Tap Next>. If you are using a keyed in origin point,
enter the coordinate of the origin and tap Next>.
5. The next page will display the local geodetic
coordinate of the origin Reference Point and the
Ground Scale
factor calculated for that point. The
scale factor is the inverse of the combined scale
factor for the selected map projection zone at the
origin reference height, and it is automatically
calculated based on your reference position. If you
wish to use a different scale factor, tap Override scale
calculated from location
and enter your value in the
Ground Scale Box. Tap Next>.