# To manually calibrate points

Key in the grid coordinates of your control points. Alternatively, transfer them from your office computer, or use a conventional instrument to measure them. Then measure the points with GNSS.

1. Tap and select Measure / Site calibration.
2. For Scale factor only jobs:

- If the job uses ground coordinates, select Ground.
- If the job uses grid coordinates, select Grid.

3. To add a point to the calibration, tap Add.
4. Enter the name of the grid point and the GNSS point in the appropriate fields.

The two point names do not have to be the same, but they should correspond to the same physical point.

5. Change the Use field as required and tap Accept.

The calibration residuals screen appears.

6. Tap Results to see the horizontal and vertical shifts that the calibration has calculated.
7. To add more points, tap Esc to return to the calibration screen.
8. Repeat steps 3 through 6 until all the points are added.
9. Do one of the following:

- If the residuals are acceptable, tap Apply to store the calibration.
- If the residuals are not acceptable, recalculate the calibration.