Spectra Precision Survey Pro v4.6 Ranger User Manual - Manual (Page 231)

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GPS Coordinates In
Survey Pro
GPS positions are measured in a 3D coordinate system, which models
the earth using an ellipsoidal shape. The horizontal position is
usually given as two angles, relative to the ellipsoid axes, called
latitude and longitude. The vertical position is usually given as a
linear distance, perpendicular to the ellipsoid, called height. Most
survey projects use horizontal coordinates on a plane which
approximates a small piece of the ground assuming a ‘flat earth’. The
horizontal position is usually given as two linear distances, called
northing and easting. The vertical position is usually given as a
linear distance, describing the direction water will flow down hill,
called elevation. The usual method to convert latitude, longitude and
height to northing and easting is to use a map projection. The usual
method to convert height to elevation is to use a geoid model. This
section describes different ways to manipulate geodetic coordinates
with both Survey Pro and ForeSight DXM and the methods Survey
Pro uses to calculate local coordinates from GPS measurements. In
this section, you will learn:
¾ A description of the horizontal and vertical projection modes
used by Survey Pro to transform geodetic position into local
coordinates.
¾ A description of the coordinate system database used by
Survey Pro.
¾ How to use the Survey Pro Edit Points screen to edit plane
and geodetic locations, and geodetic flags.
¾ How to use the Survey Pro Import menu to import
coordinates and coordinate systems, and how to merge GPS
coordinates from a *.GPS file.
¾ How to use ForeSight DXM (DXM) and Trimble Geomatics
Office (TGO) to manage job files with geodetic coordinates
from GPS measurements and coordinate system definitions.