Coordinate Systems - Tripod Data Systems SURVEY PRO User Manual

Z
λ
X
Fig. 1: Ellipsoidal Geodetic
Coordinates
Survey Pro does not require choice of a specific vertical datum. For
RTK applications, elevations are solved relative to the base using the
vertical localization adjustment. Therefore, the vertical datum is
established by the datum of the base elevation.

Coordinate Systems

A coordinate system is a way to describe positions in a datum.
Coordinate systems range from simple Cartesian (y,x) or (N,E)
positions on a flat plane to complex geodetic latitudes and longitudes
on a reference ellipsoid.
Below is a description of some coordinate systems common in
surveying:
•
Northing, Easting, Elevation
Survey projects usually use simple plane coordinates. You assume
your local datum models a flat earth, and you calculate coordinates in
a Cartesian system where the simple laws of plane trigonometry
apply. When a vertical coordinate is required, most survey projects
require orthometric elevations.
φ
•
Lat, Lng, Ht
Geodetic horizontal coordinates are usually
expressed as two angles called latitude and
longitude (φ, λ). Geodetic vertical coordinates
are usually expressed as the distance above the
ellipsoid called height. The angles describe a
point's position on the surface of the reference
ellipsoid. The height describes the altitude
Y
normal to the surface of the reference ellipsoid.
GPS Coordinates
81