1. Enter the station number, Northing and Easting into the fields requested. Leave the Elevation field .

2. Enter the point number of the backsight from which you plan to carry the elevation. If the coordinates of the backsight are currently in the job, take the backsight reading, including distance, to carry the elevation to the station record.

3. If the backsight position is not recorded in the SDR, enter the backsight number. The SDR will ask for the coordinates or azimuth of the backsight. Select coordinates and enter the elevation of the backsight. Leave the Northing and Easting fields . The SDR will notify you that the backsight azimuth cannot be calculated. Enter the azimuth if it is known and proceed with the survey. If the backsight azimuth is not known, enter an arbitrary azimuth (since you are only concerned with elevation at this time) and take an observation to the backsight point. The elevation has will be calculated and written to the station record.

4. Exit from the routine and re-enter the routine you are going to collect. Accept the station number and enter the actual backsight that you intend to use for the survey. Continue collecting data as planned.