Surveying - Carpenter's and Builder's Math, Plans, and Specifications - page 229

Figure 6-16 Typical EDM/Theodolite setup. (Courtesy of Wild Heerbrugg)

The laser level can generate a vertical reference plane for position-
ing a wall partition or for setting up forms (see Figure 6-18). It can
produce accurate height gaging and alignment of ceilings, moldings,
horizontal planes, and can accurately locate doorways, windows,
and thresholds for precision framing and finishing (see Figure 6-19).
The laser level can aid in leveling floors, both indoors and out. It
can be used to check stairs, slopes, and drains. The laser beam is
easy to use and accurate in locating markings for roof pitches, and
it works well in hard-to-reach situations (see Figure 6-20). The laser
beam is generated by two AAA alkaline batteries that will operate
for up to 16 hours.