# To measure a position in the tunnel

Use the Position in tunnel function to:

- Measure a position at any station within the tunnel.
- Compare the position with the design parameters of the tunnel.

To measure the position:

1. Start a survey.
2. Tap and select Survey / Position in Tunnel.

3. Select the tunnel file. Tap Accept.

   Information on the current position appears at the bottom of the screen. See Current position information.

4. If the tunnel has more than one surface, select the surface to measure relative to. To select the surface you can:

- Tap and hold on the plan view and tap Select surface. Select the surface from the list.
- Tap the template surface.

5. Point the instrument at the position you want to measure. Tap Store.

6. Enter the Position settings. Tap Accept.

7. Enter the Position tolerances. Tap Accept.

   The position is stored.

8. To exit the plan view, tap Esc.