Civil Engineering Reference
In-Depth Information
The combination laser and spirit level quickly and accurately lays
out squares and measures plumb. No protective eyewear is needed.
The laser operates on a wavelength of 635 nm and can have an
extended range up to 250 feet.
Summary
Leveling, in surveying, is the operation of determining the compar-
ative levels of different points of land for the purpose of laying out
a grade or building site by sighting through a leveling instrument at
one point to a leveling staff at another point.
The transit is designed and used for measuring both horizontal
and vertical angles. It is a telescope mounted in standards attached
to a horizontal plate, called the limb. The transit is generally pro-
vided with a compass so that the bearing of any given line with the
magnetic meridian may be determined. It also has a spirit level at-
tached to the telescope so that it may be brought to a horizontal
position and made to serve as a level.
A stadia is a device used for measuring distance. It consists essen-
tially of two extra parallel hairs in addition to the ordinary crosshairs
that are used in transit or level telescopes. When using the stadia,
distances are measured by observing through the telescope of a tran-
sit.
The laser level is rather inexpensive and easily used. It can be
utilized in the squaring of steps, locating doors, windows, and many
other squaring and leveling operations.
Review Questions
1.
What are the three lines of the level?
2.
What is a transit?
3.
What are the fine lines of a transit?
4.
Name the various leveling rods used for measuring distance.
5.
Explain the terms
backsight
and
foresight
when used in level-
ing.
6.
What is a stadia?
7.
Where is the laser level most useful?
8.
What is leveling in terms of surveying?
9.
Why is it important to have square corners and level floors in
a building?
10.
How can a laser actually establish a useable level reference?
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