Default Projection (Transverse Mercator) dialog

This dialog appears, if you do the following:

1. Do one of the following:
   • If your currently selected coordinate system is Default:Default: Select the main menu command File > System Properties, set the focus onto the Select coordinate system setting and click the browse button.
   • If your currently selected coordinate system is a different one: Select the main menu command File > System Properties, set the focus onto the Select coordinate system setting and click the browse button. The Select Coordinate System dialog appears. Click New System.

   The Select Coordinate System Type dialog appears.

2. Select Default Projection (Transverse Mercator) and click Next.

Use the dialog to select the Transverse Mercator projection type, and optionally to change some of the projection parameters.

Using the default projection

Automatically calculate projection parameters: By default, this option is selected. This means that each station or point has its own coordinate system which is not related to a global coordinate system.

Note - If Automatically calculate projection parameters is selected, editing any of the other options of the dialog has no influence on the calculation of coordinates.

Using a purely local coordinate system

For monitoring purposes, often pure local coordinate systems are used instead of a global projection system. These systems are purely local in the sense that no geocentric reference is given. If known, you can freely define origin, scale and false easting/northing of a local coordinate system.

For providing fixed vales for the default projection (and thus creating your purely local system), remove the selection from the Automatically calculate projection parameters check box.

For the display of coordinate values, Trimble 4D Control Server additionally needs information, in which direction the values are to be displayed as positive. One can individually set the positive coordinate directions by selecting the respective options (North or South, East or West).

Next step

Click Next. One of the following happens:

• The Select Datum Transformation dialog appears, if the selected coordinate system zone does not provide a pre-defined datum transformation (for example, with the zones assorted in the UTM coordinate system group).
• In most cases, a datum transformation is already part of the zone information. Therefore, the Select Geoid Model dialog is the next one to appear. Use it to specify the geoid model to be applied, if any.