Spectra Precision Survey Pro v4.5 Ranger User Manual - Manual (Page 210)

User’s Manual – GPS Mode
200
G
re
en
w
ic
h
M
e
ri
d
ia
n
Equator
φ
λ
X
Z
Y
h
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.
• 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
normal to the surface of the reference ellipsoid.
Fig. 1: Ellipsoidal Geodetic
Coordinates