Field
Survey Parties
The size of a field survey party depends
upon the survey requirements, the equipment available, the method of survey,
and the number of personnel needed for performing the different functions. Four
typical field survey parties commonly used in the SEABEEs are briefly described
in this section: a level party, a transit party, a stadia party, and a plane
table party.
LEVEL PARTY.- The
smallest leveling party consists of two persons: an instrumentman and a
rodman. This type of organization requires the instrumentman to act as note
keeper. The party may need another recorder and one or more extra rodmen to
improve the efficiency of the different leveling operations. The addition of
the rodmen eliminates the waiting periods while one person moves from point to
point, and the addition of a recorder allows the instrumentman to take readings
as soon as the rodmen are in position. When leveling operations are run along
with other control surveys, the leveling party may be organized as part of a
combined party with personnel assuming dual duties, as required by the work
load and as designated by the party chief.
TRANSIT PARTY.- A
transit party consists of at least three people: an instrumentman, a head
chainman, and a party chief. The party chief is usually the note keeper and may
double as rear chainman, or there may be an additional rear chainman. The
instrumentman operates the transit; the head chainman measures the hori-zontal
distances; and the party chief directs the survey and keeps the notes.
STADIA PARTY.- A
stadia party should consist of three people: an instrumentman, a note keeper,
and a rodman. However, two rodmen should be used if there are long distances
between observed points so that one can proceed to a new point, while the other
is holding the rod on a point being observed. The note keeper records the data
called off by the instrumentman and makes the sketches required.
PLANE TABLE PARTY.- The
plane table party consists of three people: a topographer or plane table
operator, a rodman, and a computer. The topographer is the chief of the party
who sets up, levels, and orients the plane table; makes the necessary readings
for the determination of horizontal distances and elevations; plots the details
on the plane table sheet as the work proceeds; and directs the other members of
the party.
The rodman carries a stadia rod and
holds it vertically at detail points and at critical terrain points in the
plotting of the map. An inexperienced rodman must be directed by the
topographer to each point at which the rod is to be held. An experienced rodman
will expedite the work of the party by selecting the proper rod positions and
by returning at times to the plane table to draw in special details that he may
have noticed.
The computer reduces stadia readings to
horizontal and vertical distances and computes the ground elevation for rod
observations. He carries and positions the umbrella to shade the plane table
and performs other duties as directed by the topographer. At times, the
computer may be used as a second rodman, especially when the terrain is
relatively flat and computations are mostly for leveling alone.
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