designate the exact point of reference for angular and linear measurements. To assist in recovering a
station, surveyors drive a reference (witness) stake into the ground so that it slopes toward the station.
Surveyors must write the identification of the station on the reference stake or attached tag using a
lumber crayon or a china-marking pencil. Signal cloth may also be tied to the reference stake to further
assist in identifying or recovering a station.
j. Station Signals. A signal must be erected over survey stations to provide a sighting point for the
instrument operator. The survey target set is the most commonly used signal.
k. Traverse-Party Organization. The number of personnel available to perform survey operations
depends on the unit's TOE. The organization of these people into a traverse party and the duties
assigned to each member will depend on the unit's SOP. The organization and duties of a traverse party
are based on the functional requirements of the traverse.
l. Team Members. The party chief selects and marks the locations of the traverse stations and
supervises the work of the other party members. The party chief also assists in survey reconnaissance
and planning. Additional team members perform the following duties:
The instrument operator measures the horizontal angles and distances at each traverse station.
The recorder keeps the field notes in a field notebook and records the measured angles and
distances and all other information pertaining to the survey.
The rodman assists the party chief in marking the traverse stations, removes the target from
the rear station (when signaled by the instrument operator), and moves the target forward to
the next traverse station.
m. Azimuth Computations. The azimuth of a line is the horizontal angle (measured clockwise) from
a base direction to the line in question. To compute a traverse, surveyors determine an azimuth for each
traverse leg (section). The azimuth for each succeeding leg is determined by adding the value of the
measured angle at the occupied station to the value of the azimuth from the occupied station to the rear
station. Upon occupation of each successive station, the first step is to compute the back azimuth of the
preceding leg (the azimuth from the occupied station to the rear station).
n. Azimuth Adjustment. Surveyors must determine the need for adjustment before beginning final-
coordinate computations. If the angular error of closure (AEC) falls within the computed allowable
error (AE), the azimuths of the traverse may be adjusted. Use the following formula to determine the
allowable AEC for third-order, Class I traverse:
EN0593
3-30
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