How to Take Survey Elevation Shots

A survey elevation shot, an important tool in both engineering and construction, determines the elevation of an unknown point by referencing a known point, called a benchmark, or BM. A survey elevation shot achieves this by measuring vertical distances between different points by reading a leveling rod through the cross-hairs of an engineer's level. Surveyors use this process in topographic surveys and road, house and sewer construction. This task requires a partner to hold the leveling rod.

Certified survey technicians survey for elevation on construction sites.

Step 1

Find a point of known elevation -- a benchmark, or BM -- to which you will reference your survey elevation shots. You can use any object or point as a reference provided you know its exact elevation.

Step 2

Label five columns in your field book with the headings Back-Sight (BS), Height of Instrument (HI), Fore-Sight (FS), Elevation (ELEV) and Description (DESC).

Step 3

Fasten the engineer's level to the tripod with the fastening screw and level it using the fine leveling screws. Set the level up in a location where you can see both the BM and the area in which you wish to determine an elevation.

Step 4

Instruct your partner to hold the leveling rod vertically on the BM. Sight the rod with the engineer's level and record the reading in the field book. This is your BS. To determine the HI, add this reading to the BM elevation and record this number in the field book in the ELEV column.

Step 5

Instruct your partner to move the leveling rod to the other points where you wish to determine elevations. Record the readings of the leveling rod under FS in the field book. Include a description in the column labeled DESC for each point that will allow you to recall which FS corresponds with each location.

Step 6

Subtract the recorded FS from the recorded HI. Record the values in the ELEV column of your field book. You now have elevations of each point on which you have taken a shot.