CHAPTER 12
DIRECT LINEAR MEASUREMENTS AND
FIELD SURVEY SAFETY
This chapter covers the various duties, the
techniques, and the skills a chaining crew member
must learn thoroughly concerning chaining opera-
tions and some of the devices used in chaining
itself. DIRECT LINEAR MEASUREMENTS, as
used in this chapter, are methods used for
measuring horizontal distances with a tape (or
chain) and/or with electronic distance-measuring
instruments presently available in the military.
As a crew member, you should be concerned
not only about the task at hand but also about
the potential hazards to which you may be
exposed in the field. It is important, therefore,
that you recognize the precautions and safety
measures applicable to the survey field crew. In
this chapter we shall discuss these precautions
and safety measures and also additional duties
normally performed by the crew.
DUTIES OF A CHAINING
CREW MEMBER
During a typical chaining operation, it is
possible that many and varied duties other than
the actual chaining itself are to be undertaken as
part of the whole process. To prepare the field
chaining party for the task ahead, we shall present
some of these duties, as applicable. In some
cases, these duties can be modified or tailored,
contingent upon the mission, terrain features, and
other conditions that may affect the speed and
accuracy of the operation.
GIVING HAND AND VOICE SIGNALS
During fieldwork, it is essential that you
communicate with the other members of the
survey party over considerable distances. Some-
times you may be close enough to use voice
communication; more often, you will use hand
signals. Avoid shouting; it is the sign of a
beginner. Standard voice signals between chain-
men must be used at all times to avoid misunder-
standing. There are also several recommended
hand signals, most of which are shown in figure
12-1. Those shown are recommended, but any set
of signals mutually agreed upon and understood
by all members of the party can also be used. It
is important to face the person being signaled.
Sometimes, if it is difficult for you to see the other
person, it helps to hold white flagging in your
hand when giving signals. When signals are given
over snow-covered areas, red or orange flagging
is more appropriate.
Explanations of the hand signals shown in
figure 12-1 are as follows:
1. ALL RIGHT. The “all right” is given by
the instrumentman when the alignment is OK for
a plumb line, a range pole, a stake, a hub, or any
other device used as a target, or when the
instrumentman has finished all activities at your
location.
It is given by waving both arms up and
down while extending them out horizontally from
the shoulders. If the instrumentman, in aligning
a target, extends both arms out horizontally from
the shoulders without waving them, the signal
means that the target should be held steady while
a quick check of its position is being made.
2. MOVE RIGHT OR LEFT. This signal is
given by the instrumentman when lining in a target
on a predetermined line. It is given by moving the
appropriate hand outward from the shoulder. A
slow motion of the hand means that you must
move a long distance; a quick, short motion
means that you must move a short distance.
3. GIVE ME A BACKSIGHT. This signal
is given when the instrumentman wants a target
held at a previously located point. It is given by
extending one arm upward with the palm of the
hand forward.
4. GIVE ME A LINE OR THIS ISA HUB.
This signal, given by the rodman or the chainman,
is intended to indicate a hub or to ask for a line
on the point indicating the exact location.
It is given by holding a range pole
horizontally overhead, then moving it to a vertical
12-1
