If you use Topcon surveying equipment on your site and operate in a local grid system, it should be possible to generate a Topcon control point file (.gc3) from your rover or software suite. 

This file type can be opened with Topcon's 3D office software, and the parameters from the calibration can be copied into a form in Propeller's Create new site flow to set up your site for local processing.

Start by clicking Create a new site in the Propeller Viewer sites dropdown (below), or in the beginning of the Create new dataset flow.

Give your site a name and click Create Site

You should then see the option to configure your newly created site for processing in your local coordinate system. If you do not see this option, please click Contact Propeller.

Now click the Topcon GC3 file option to proceed.

The first step to configure your localization is to select the .gc3 file that describes your site control points. Propeller cannot read this file automatically, so although it is required to fill in the parameters from the file in the next step, it is important that we have a copy of the original file in case of need to review the site configuration.

Open this .gc3 file with Topcon 3D Office software by opening the program and importing your control file. Once the file has loaded, it is possible to find the calibration parameters in the file by going to the Project dropdown and selecting Control points... as below.

Important: Please first check if your local site calibration uses a geoid. This can be determined by checking the Coord. System tab and checking the "Use geoid model" field. If this is not blank, please discontinue this flow and contact Propeller Support.

Select the Localization tab in the dialog (seen below). This shows the values that need to be copied directly into Propeller. Note that the latitude and longitude have been obscured for privacy.

These values can be copied into Propeller by double-clicking on the fields, right-clicking and clicking Copy. They need to be copied into their corresponding fields as below. Be careful to select the right distance and angular unit in which values are expressed in 3D Office.

Once all fields have been entered correctly, click Save.

We now require that a test point is entered so that we can validate that the local to global transformation is being calculated correctly.

Enter a local Easting/Northing/Elevation (optional) from the list of control points in your .gc3 file. These can be accessed by clicking the Control points tab in the same dialog in Office 3D, as below.

Double-click one of the points which has a H.Error and V.Error value (i.e. the point was used in the calculation of the calibration). The dialog shown on the right will appear, exposing the local and global coordinates. (Again note that the lat/lng has been obscured.)

Copying in the Northing/Easting/Elevation in your local system will show a map with the corresponding global position of your point, as below.

You must now enter the corresponding global (latitude/longitude/height) values of the chosen point, as below:

Note: If your calibration uses a geoid, the global height coordinate will not be correct. Please discontinue and contact support.

If we cannot transform the point correctly, the below error will show.

Please double check that all numeric values have been copied over verbatim (including minus signs, where applicable). Clicking Update at the bottom of the parameter input form will save your changes.

If the conversion result is still not correct:

Sometimes the value for horizontal rotation is shown as a positive value in 3D Office, even though it is required to be a negative value. Please try adding a minus sign to the value in the Rotation field in the form and click Update. If this does not solve the problem, please contact Propeller.

If the transform is correct, click Save. This will finalize the setup of your site. You can now upload data to this site and it will be processed in your local system.

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