Specifications

Coordinate Transformation 63
Coordinate
5
Coordinate Transformation
This chapter describes the coordinate transformation features of your receiver.
Background
GPS determines the three-dimensional positions of surveyed points based on the WGS84
datum. These coordinates are either presented as geocentric cartesian coordinates (X,Y,Z)
values or geodetic coordinates (latitude, longitude, ellipsoidal height).
There are circumstances where it would be desirable to have positions represented in a
different reference frame or format, i.e. based on a different datum or projected onto a
plane (grid coordinates).
The Z-Surveyor provides the following on-board tools to transform WGS84 coordinates
into various formats and reference frames:
1. Datum to Datum transformation
Using this feature, WGS84 coordinates can be transformed into coordinates
based on another datum.
2. Datum to Grid conversion
With this tool, a grid system can be defined to convert geodetic coordinates into
grid coordinates.
3. Elevation Modeling
Using an on-board geoid model, ellipsoidal heights can be transformed into
orthometric heights using this capability.
Table 5.1 provides an overview of User Coordinate Transformation functions for your
receiver.
Table 5.1: User Coordinate Transformation Functionalities
Transformation Description
Datum to Datum 3D (7-parameter) datum transformation between two Cartesian XYZ systems
associated with the WGS84 datum and local datum defined by the user.