Leica GPS1200 Series Technical Reference Manual page 920

Determine Coordinate System - General
Transformation Characteristic
Requirements
Area
Advantage
Disadvantage
GPS1200
Description
• The positions and heights are known in
WGS 1984 and in the local system for at least
three points. Four points or more are recom-
mended in order to obtain higher redundancy.
• Parameters of the local ellipsoid.
• Parameters of the local map projection in order to
convert between grid coordinates and geodetic
coordinates.
• Parameters of the local geoid model in order to
convert between orthometric and ellipsoidal
heights. This is not compulsory.
Especially wide networks with large height differ-
ences. Local grid coordinates must be accurate.
• Accuracy of the measurements is maintained.
• It may be used over any area as long as the local
coordinates, including heights, are accurate.
• The local ellipsoid and map projection must be
known for the local grid coordinates.
• In order to obtain accurate ellipsoidal heights the
geoid separation at the measured points must be
known. This may be determined from a geoid
model. Refer to "13.2 Terminology".
920