# To stake out a DTM

A DTM is a gridded digital terrain model, which is a type of topographical surface.

1. Tap Stakeout / DTMs.

2. Select the file to be used. The list includes all DTM files in the current project folder.

3. If required, in the Offset to surface field, specify an offset to the surface. Tap to select whether the offset is to be applied vertical or perpendicular to the surface.

   By default, the V. Dist, Perp. Dist and Design elevation stakeout deltas are shown in the stakeout navigation screen when staking out a DTM. To change the deltas shown, tap Options and In the Deltas group box, tap Edit. Make your changes and tap Accept and then tap Accept again to return to the Stake out DTM screen.

4. If required, change the height of the target or antenna height. If the target or antenna height have not been defined, the elevation and cut/fill will be null (?).

5. Tap Start.

   The coordinates of the current position and the distance above (cut) or below (fill) the DTM are shown. When staking out the DTM, if you are outside the extent of the DTM or in a "hole", the DTM elevation and cut/fill will be null (?).

   Unless you are using a conventional instrument that supports tracking, the values appear only after you have taken a distance measurement.

6. When the point is within tolerance, tap Measure to measure the point.

   When using a Trimble SX12 scanning total station in TRK mode with the laser pointer enabled, the Stakeout screen shows the Mark point softkey instead of the Measure softkey. Tap Mark point to put the instrument into STD mode. The laser pointer stops flashing and moves to position itself at the EDM location. When you tap Accept to store the point, the instrument automatically returns to TRK mode and the laser pointer resumes flashing. To remeasure and update the stakeout deltas, tap Measure after you tap Mark point and before you tap Accept. For more information, see EDM settings.

7. Tap Accept to store the point.
8. If you selected the View before storage option, the staked deltas you selected in the Stakeout options screen are shown. Tap Store.