Requires an LP360 Land Basic or LP360 Land Standard license.

Introduction

What are TGCPs? 

TGCPs, or TrueView GO Control Points, are used in the context of the TrueView GO to enhance the accuracy of 3D mapping and surveying data. They serve as reference points with known coordinates, which are used to align and optimize the data collected by the GO's integrated GNSS RTK and SLAM (Simultaneous Localization and Mapping) technologies.

By incorporating TGCPs, you can ensure that the spatial data captured by the TrueView GO is accurately georeferenced, improving the overall precision of your mapping projects. This is particularly useful in applications like construction, forestry, and infrastructure inspection where high accuracy is crucial.

Collecting TGCPs

It is possible to georeferenced the point cloud using control points surveyed with the TrueView GO during scanning. A minimum of four control points is needed to properly reference a point cloud, increasing this number will improve point cloud alignment. Remember to Place the metal tip over the control point and select “Add control point” on the tablet.

Figure 1: Collecting TGCPs with the TrueView GO

TrueView GO Ground Control Point Measurements dialog

The TrueView GO Ground Control Point Measurements dialog is opened from the Import Cycle dialog.

Figure 2: TrueView GO Ground Control Point Measurements dialog

TV GO Control Point Measurements

This grid displays the control points collected during the scan with the TrueView GO. The XYZ position will be in an internal local project coordinate system.

Calculate Errors

After pairing, select "Calculate Errors" to populate the error column with the error of each control point in relation to the paired point.

Imported Ground Control Points

This grid displays the control points after import. The positions must be in the same coordinate reference system as the project.

File Order

Options in the dropdown are ENH or NEH, to specify the column order of the CSV file to be imported.

PP131,5654721.269,32404008.225,281.101
PP132,5654736.233,32404010.793,281.057

Import...

Opens the file browser to select the control points file to be imported into the TrueView GO Ground Control Point Measurements dialog as the Imported Ground Control Points.

Clear

Removes the imported control and clears the assignments.

Save Assignments

Saves the point pair assignments.

Delete Assignments

Removes the point pair assignments.

How to use TGCPs

1. TrueView GO Cycles that contain TGCPs will show the GCPs status as Unassigned during Import Cycle and displays the editable . Note: the GCPs status shows as None if no TGCPs were acquired during the Cycle.
2. Selecting the in the GCPs column opens the TrueView GO Ground Control Point Measurements dialog (Figure 2).
3. In the TrueView GO Ground Control Point Measurements dialog (Figure 2), select Import... to import control points.
4. Pair the TGCPs in the TV GO Control Point Measurements grid on the left side of the dialog with the imported control points by selecting the corresponding name in the GCP column for each TGCP to reflect the Name as seen in the Imported Ground Control Points on the right side of the dialog.
5. After pairing, select Calculate Errors to verify.
6. Once satisfied the pairings are correct, select Save Assignments.
7. The GCPs status on the Import Cycle wizard will now show as Assigned.
8. Continue with the Import Cycle workflow to use the TGCPs during the point cloud generation.