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4.3.3. Taping Horizontal Distances
Taping may be used to determine the unknown distances between two fixed
points on the ground, or it may be used to set marks at specified distances on the
given line. This operation is called setting marks for line and distance. Setting
marks for line and distance typically involves the use of theodolite to establish the
proper direction of the line and to help keep the marks set by the tape person
exactly on that direction.
Clearly, at least two surveyors are needed to tape a distance-a front, or head,
tape person to hold the front end of the tape and a rear tape person to hold the back
of the tape. It is best, for taping to be performed with a three-person crew; the third
member of the group provides valuable assistance in assuring proper tension and
alignment of the tape, setting the chaining pins, double checking tape readings.
When a series of marks are set on a line at measured distances, surveyor uses a
standard system of identifying the marks; the marks are called stations. The
stations may be very temporary or somewhat long lasting. Stationing is particularly
important when doing profile leveling, as well as when setting marks for line and
distance in route survey.

4.3.4. Horizontal Measurement on Sloping Ground and slop measurements
In taping on uneven or sloping ground, it is standard practice to hold the tape
horizontal and use a plumb bob at one or both ends. It is difficult to keep the plumb
line steady for height above the chest. Wind exaggerates the problem and may
make accurate work impossible.
When a 100 m length cannot be held horizontally without plumbing from
above shoulder level, shorter distances are measured and accumulated to total a full
tape length. This procedure, called breaking tape.

Fig.4.10 Breaking tape

In measuring the distance between two points on a steep slope, rather than
break tape every few meters, it may be desirable to tape along the slope and
compute the horizontal component. This requires measurement also of either the
angle of inclination A or the difference in elevation h. Breaking tape is more time
consuming and generally less accurate due to the accumulation of random errors
from making tape ends and keeping the tape level and aligned for many short
sections.

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