# To create a reference line

Select Refline to create a baseline by taking measurements to two known or unknown baseline definition points. All subsequent points are stored relative to the baseline as a station and offset.

Because the refline calculation is a grid calculation, you can only use existing points that can be viewed as grid coordinates. You can use 2D and 3D grid coordinates to define the baseline.

1. Tap and select Measure / <Style name> / Refline.
   1. When prompted, use the electronic level to level the instrument. Tap Accept.

   2. Set the corrections associated with the instrument.

      If the Corrections screen does not appear, tap Options and enter the correction information.

   3. Enter an Instrument point name and Instrument height, if applicable.

   4. Tap Accept.

2. Enter the Point 1 name, and Target height.

   If point 1 does not have known coordinates, default coordinates are used. Tap Options to change the default coordinates.

3. Tap Meas 1 to measure the first point.

4. Enter the Point 2 name, and Target height.

   You can use a point with known coordinates for point 2 only If point 1 has known coordinates. If point 1 does not have known coordinates, default coordinates are used. Tap Options to change the default coordinates.

5. Enter the Refline azimuth.

   If point 1 and point 2 have known coordinates the value shown is the computed refline azimuth, otherwise the value is 0°.

6. Tap Meas 2 to measure the second point.

   The instrument point coordinates are shown.

7. Tap Store.

   The software creates a baseline between the two points, using the naming scheme "<Point 1 name>‑<Point 2 name>". You can enter the Start station and Station interval.

   If the line between the two points does already exist, the existing station is used and cannot be modified.