Define a Geoid Sub-Grid

If the geoid file you want to use for data collection is too large, define a subsection of the area (sub-grid) to use before uploading to a field device. This saves upload time and field device memory.

Note: When you download or import data into a project, the geoid sub-grid used by the imported data must correspond with the geoid defined for the project's coordinate system.

Prerequisites:

See the Subscription Plans page. For a license matrix by command, see the License page in the TBC Community. Also see View and manage licensed features.

To create a geoid sub-grid:

Do one of the following:
- Select Geoid Sub-Gridding in Survey > Network.
- In the Device pane, with a device connected, click Tasks and select Upload geoid (ggf) file.
The Geoid Sub-Gridding command pane displays.
If needed, select the folder containing the installed geoid files in the Folder (.ggf) list, or click the Browse button and navigate to the folder.
Note: The default location for .ggf files is: C:\Trimble Synchronizer Data\PC\Trimble GeoData\.
Select a geoid file in the Geoid File (.ggf) list.
Right-click and select Create sub-grid from the context menu. The Create Geoid Grid File dialog displays. The whole globe is visible, and the geoid is centered. In the Geoid File Properties group, the size of the whole geoid appears in the Size box.
In the Suffix to Append box, type text to attach to the end of the original geoid file name to define the sub-grid. The complete file name appears as you type the suffix.
For example, if you will be collecting data in Baja, Mexico, add Baja as the suffix to the geoid Mexico97.ggf to create the file Mexico97Baja.ggf.
If needed, uncheck borders or rivers in the Globe Properties group to simplify the display.
Click the Zoom In button to zoom in to the extents of the geoid. For explanations of the other viewing tools, see Geoid Sub-grid Options.
Click the Select button, and draw a window around the portion of the geoid that you need to create a sub-geoid. The size of the geoid sub-grid appears in the Size box.
Note: You cannot adjust the sub-grid window that you draw, but you can redraw it multiple times.
Click Save. The Save Geoid Grid File As dialog displays.
Click Save again. The geoid sub-grid file appears in the geoid list just below the original geoid file.