071-332-5000 (SL3) - Prepare an Operation Overlay

Note.  Overlay
techniques involve the use of military
symbols to portray, in a condensed
form, the plans, orders, and
information concerning a military
operation.

1.   Register the overlay.

a.
Orient the overlay
material over the map area to the
annotated portion and temporarily
attach it to the map with the tape.

b.
Trace the grid
intersections nearest the opposite
corners of the overlay and label
each with the proper grid
coordinates.

2.   Plot new detail. Use colored pencils or markers in
standard colors, when available, to
plot any detail (FM 101-5-1);
otherwise, plot the activity you wish
to show with a pen or pencil that
makes a lasting mark without cutting
the overlay. Use standard military
symbols where possible. When the
author invents nonstandard symbols,
they must be identified on the edge of
the overlay. 
Show only that detail with
which the document is directly
concerned. 
Standard colors are-

a.
Blue or black.  Friendly units, installations, equipment, and activities.

b.
Red. 
Enemy installations,
equipment, and activities.

c.
Yellow. 
Any areas of chemical,
biological or radiological
contamination.

d.
Green. 
Any man-made obstacle.

Note.  If only one
color is available, enemy symbols are
depicted with double lines.

3.   Mark the overlay classification. The classification
of the overlay is dependent upon
classification of the order used to
prepare the overlay. Mark the top and
bottom of the overlay with the
classification.

4.   Recognize overlay
techniques.

a.
Use solid and broken
lines. 
When the location of a unit
or installation or coordinating
detail (for example, line of
departure or boundary) is in effect
and will continue, or is made
effective by the order prepared, the
appropriate symbol is shown by solid
lines. The symbol indicating any
proposed or future location, or
coordinating detail to become
effective later, is shown by broken
lines.

b.
Boundaries.

(1) 
Boundaries show areas
of tactical responsibility. 
In the offense, these are
referred to as zones of action. 
In the defense and
retrograde, they are referred to
as sectors of responsibility. 
When described orally,
lateral boundaries are described
from rear to front in the offense
and from front to rear in the
defense and retrograde.

(2) 
Rear boundaries are
used when the area of
responsibility for forward units
must be precisely defined. 
When a rear boundary is not
delineated, the rear limit of a
unit area of responsibility is
determined by visualizing a rear
boundary drawn generally parallel
to the front, preferably along a
natural terrain feature, and
connecting at the rearward limit
of the unit lateral boundaries.

(3)  If a rear boundary
is shown, the size indication
along the boundary corresponds to
the low unit. Arm or branch is
shown when required to prevent
confusion (figure 071-332-5000-1).

Figure 071-332-5000-1.
Rear Boundary

(4) 
Desirably, boundaries
are drawn along terrain features
easily recognizable on the ground,
and are situated, if possible, so
the key terrain features, avenues
of approach, and river are wholly
inclusive of the one unit. They
are shown by a solid line if
currently in effect or made
effective by the order prepared.
Their use is based on the
techniques and tactics peculiar to
the type of tactical operation in
which they are used.

(5) 
Future or proposed
boundaries are shown by a broken
line and  labeled
to indicate the effective time, if
appropriate (figure 071-332-5000-2).

Figure 3-071-332-5000-2.
Proposed Boundary

(6) 
A symbol is placed on
the boundary to show size and
designation of the highest units
that share the boundary.

(7) 
If the units are of
unequal size, the symbols of the
higher unit are shown and the
designation of the lower is given
completely to show its size. The
boundary between the 52d Infantry
Division and the 230th Infantry
Brigade (separate) is shown in
figure 071-332-5000-3.

Figure 071-332-5000-3.
Lateral Boundary

(8) 
On overlays or sketches
accompanying written or oral
orders that specify task
organization, unit designation on
battalion boundaries indicate the
numerical designation. If the
battalion is organized into a task
force, the letters “TF”
precedes the numerical
designation. A unit symbol is
identified as task force by
placing the symbol (||) over the
unit size designation (||).
Company boundaries are labeled
with the appropriate letter unless
the company is organized into a
team. In the latter case, the
boundary is labeled with the
abbreviation “TM” and the
letter designation or a code name.
On other boundaries, only the unit
designation needed for clarity is
required. 
Branch designations may be
added when necessary for clarity. 
When unequal-size units
have a boundary in common, the
designation of the smaller unit is
spelled out.

c.
Axis of advance.

(1) 
An axis of advance
arrow should extend only as far as
this form of control is essential
to the overall plan. 
Normally, it is shown from
the line of departure (LD) to the
objective following an avenue of
approach. 
It indicates that the
commander may maneuver his forces
and place them freely to either
side of the axis to avoid
obstacles, engage the enemy, or
bypass enemy forces that could not
threaten his security or
jeopardize the accomplishment of
his mission. 
The commander ensures that
such deviation does not interfere
with adjacent units, that his unit
remains oriented on the objective,
and that the location and size of
the bypassed enemy forces are
reported to higher headquarters. 
Boundaries may be assigned
as an additional control measure
when using the axis of advance, if
the situation so dictates.

(2) 
An axis of advance is
shown below, identified by a code. 
It could be identified by a
unit designation (figure 071-332-5000-4).

Figure 071-332-5000-4.
Axis of Advance

(3) 
To differentiate
between a ground axis of advance
and an air assault of advance, a
twist is placed in the shaft of
the open arrow, symbolic of a
propeller (figure 071-332-5000-5).

Figure 071-332-5000-5.
Air Assault Axis of Advance

d.
Direction of attack
arrows. 
This control measure is used
when the commander desires to
specify the direction in which the
center of mass of a subordinate unit
must move in an attack to ensure the
accomplishment of a closely
coordinated plan of maneuver (for
example, in a night attack or
counterattack). 
A direction of attack arrow
should extend from the line of
departure to the objective and is
not labeled (figure 071-332-5000-6).

Figure 071-332-5000-6.
Direction of Attack Arrow

(1) 
The arrow should be
used only where necessary because
it restricts the maneuver of the
subordinate unit.

(2) 
When a unit is directed
to seize successive objectives
with its main attack along a
certain line, either one arrow
extending through the objectives
to the final objective or a series
of arrows connecting the
objectives may be used.

(3) 
The double arrowhead is
used to distinguish the main
attack for the command as a whole
(figure 071-332-5000-7).

Figure 071-332-5000-7.
Arrowhead Indicating the Main Attack

e.
Graphic portrayal of
units assigned a security mission.

(1) 
To show the general
location of a unit with a security
mission, arrows generally indicate
the terrain over which the unit
operates and the farthest
extension of its mission (figure 071-332-5000-8).

Figure 071-332-5000-8.
Unit With Security Mission

(2) 
The primary security
mission normally is shown on an
operation overlay; however, a
secondary or proposed mission is
not shown.

f. 
Graphic portrayal of
supply routes.

(1) 
The main supply route (MSR)
is the route(s) designated within
an area of operations upon which
the bulk of traffic flows in
support of military operations.  The route is labeled MSR and assigned a code name.

Note.  The term
MSR is not used below division level.

(a)  
In the defense, the
division extends the MSR forward
to the brigade trains. 
The brigade’s supply
route (SR) extends from the
battalion trains to a point at
the rear of the forward company
defense sectors.

(b)  
In the offense, the
proposed SR may be shown forward
to the objective or as far as
the battalion supply officer
(S4) can visualize the combat
service support for the
operation. 
Forward of the LD, it is
shown as a broken line.

(2) 
The symbols to show
the division (offensive action)
are shown in figure 071-332-5000-9.

Figure 071-332-5000-9.
Division Main Supply Route

(3) 
Combat service
support facilities are shown on
the operation overlay or their
location disseminated by the S4,
as appropriate.

g.
Portrayal of a unit
location.

(1) 
To show the location of
a unit on an overlay, the symbol
should be drawn so its center
corresponds with the coordinates
at which the unit is located
(figure 071-332-5000-10).

Figure 071-332-5000-10.
Location of a Unit

(2) 
To show the location of
a training area, observation
posts, or logistical activity, the
center of the symbol also should
correspond with the coordinates at
which the element is located. 
The illustration shown is
the location of an observation
post (figure 071-332-5000-11).

Figure 071-332-5000-11.
Location of an Observation Post

(3) 
The offset technique is
used for clarity when space
precludes normal placement of
symbols.  Offset staffs may be "bent" as required. 
The offset staff is dashed
for future or proposed locations. 
Offset staffs extend
vertically from the bottom center
of the symbol (except for command
posts [CP]). The end of the offset
staff indicates exact locations of
CPs and aid stations and the
center of mass for other units or
installations. 
The staff for a CP symbol
is always on the left edge (figure
071-332-5000-12).

Figure 071-332-5000-12.
Offset Technique

(4) 
Location of units.

(a)  
The locations of
attacking units normally are
indicated by boundaries (and CP
symbols, when the locations of
the CPs are known) or by unit
symbols.

(b)  
The location of the
reserve is indicated by an
assembly area symbol and by a CP
or unit symbol.

(c)  
Reserve units of a
force assigned defense position
or battle position normally are
shown by a line enclosing the
area occupied or to be
occupied-in other words, a
"goose egg." 
These positions may be
numbered or lettered for
convenient reference. 
An occupied and
unoccupied company assembly area
(reserve location) is shown in
figure 071-332-5000-13. 
An occupied and
unoccupied reserve company
battle position is shown in
figure 071-332-5000-14.

Figure 071-332-5000-13.
Occupied and Unoccupied Company
Assembly Area (Reserve Location)

Figure 071-332-5000-14.
Occupied and Unoccupied Reserve
Company Battle Position

h.
Objective(s).

(1) 
Each objective is
identified by the abbreviation
"OBJ" and a number,
letter, or name designation
(figure 071-332-5000-15).

Figure 071-332-5000-15.
Objective

(2) 
An objective assigned
by higher headquarters may be
given entirely to one subordinate
unit or may be divided. 
If divided, the objective
may be shown graphically as
separate objectives and numbered
accordingly, or may be divided
into two objectives by a boundary
line.

i.  
Pinch out a unit.

(1) 
This type operation is
indicated by drawing the boundary
across the front of the unit,
usually along a well-defined
terrain feature such as a stream,
ridge, or highway.

(2) 
The following example
indicates that Company A will be
pinched out after seizing OBJ 1;
Company B will seize OBJ 2 and
continue the attack to seize OBJ 3
(figure 071-332-5000-16).

Figure 071-332-5000-16.
Pinching Out a Unit

j.  
Defensive battlefield. 
The defensive battlefield is
organized into the covering force
area and the main battle area (MBA)
(figure 071-332-5000-17).

Figure 071-332-5000-17.
Organizing the Defensive Battlefield

k.
Defended areas.  If an area is occupied and the defense of the area is
prepared, a line (including the size
symbol of the defending unit)
encloses the area, and the closed
side of the symbol is oriented
toward the most likely enemy threat. 
If desired, the military
symbols of the unit may be entered
in the center of the enclosed area. 
A defensive area for 2d
Platoon, C Company, 1st Battalion,
6th Infantry, and a proposed
defensive area for B Company, 3d
Battalion, 52d Infantry, are shown
in figure 071-332-5000-18.

Figure 071-332-5000-18.
Defensive Area

l.  
Control measures.

(1) 
Line of departure (LD). 
The LD is a control measure
to coordinate the advance of an
attacking unit (figure 071-332-5000-19). 
The LD should be-

(a)  
Clearly defined on
the ground and on the map.

(b)  
Approximately
perpendicular to the direction
of the attack.

(c)  
Under control of
friendly units.

(d)  
Marked on both ends.

Figure 071-332-5000-19.
Line of Departure

(2) 
Line of contact (LC)
(figure 071-332-5000-20).

Figure 071-332-5000-20.
Line of Contact

(a)  
When units are in
contact with the enemy, the
frontline is shown as a series
of arcs, and the ends of the
arced line are labeled
"LC."

(b)  
If the LC is used as
an LD, it is marked LD/LC.

(c)  
If the LC is not
used, the LD is shown by a solid
line marked LD.

(3) 
Phase line (PLs). 
PLs are used to control the
progress of units for reference in
issuing orders or receiving
reports. 
They should be easily
recognized terrain features,
normally perpendicular to the
direction of advance. 
A PL is also used to
control fires and unit movement
and even to limit the advance of
attacking elements. 
Units report their arrival
at, or clearance of, a PL, but
they do not halt unless ordered to
do so. 
A PL is drawn as a solid
line with the letters PL at each
end of the line or, where
appropriate, to allow easy
identification. 
A PL is identified further
by a number, a letter, or code
name (which can be phonetic
letters, colors, flowers, cars, or
any other code system) under or
beside the PL abbreviation (figure
071-332-5000-21).

Figure 071-332-5000-21.
Phase Line

(4) 
Initial delay position
(IDP). 
An IDP is where a delaying
action begins, trading space for
time. 
The delay sector is defined
by boundaries. 
The initial and all
subsequent delay positions can be
related to a time-phased forward
edge of the battle area (FEBA). 
The initial and subsequent
delay positions are specified, and
PLs may be used to report the
progress of the battle.  The enemy is held forward of delay lines until the
specified time or until permission
is granted to withdraw.  The initial and successive delay positions are shown on
boundaries by coordination points
with a solid line between them. 
Although most IDPs are
given a code name, they may have a
number, letter, or a variety of
code names. 
The letter abbreviation (IDP)
can be to the flank of the
coordination symbol (when at the
flank, it is in parentheses) or on
the line itself. 
Its time phase is indicated
as a date-time group having a
two-digit day and a four-digit
hour, both connected. 
The month indicator can be
a three-letter type or spelled
out, depending upon the desires of
the commander. 
The letters IDP should be
placed in parentheses between the
line code name, letter, or number
and the date-time group (figure 071-332-5000-22).

Figure 071-332-5000-22.
Initial Delay Position

(5) 
Delay lines (DLs). 
These indicate where a
succeeding delay position is
located. 
Delay positions (other than
initial) are drawn the same,
except that the letter
abbreviation is along the line,
and none are placed to the flanks
at the coordinating points.

(6) 
Coordinating points.

(a)  
Coordinating points
are designated on boundaries as
specific points for coordination
of fires and maneuver between
adjacent units. 
They are indicated when a
boundary crosses the FEBA and
should be indicated when the
boundary crosses the covering
force. 
Coordinating points are
also used where DLs and internal
boundaries intersect.

(b)  
Coordinating points
should be located at some
terrain feature easily
recognizable both on the ground
and on a map. 
Their location on a
boundary indicates the general
trace of the FEBA, covering
force, or DL as visualized by
the commander who designates
them.

(c)  
The symbol for a
coordinating point is shown by a
circle with an "X"
centered in it (figure 071-332-5000-23). 
The symbol is labeled as
appropriate.

Figure 071-332-
5000-23.
Coordinating Point

(7) 
Checkpoints.  Checkpoints are shown graphically by a number, letter, or
code word inside an upright
rectangle with a pointed bottom
(figure 071-332-5000-24).
They are easily recognizable
terrain features or objects, such
as crossroads, churches, lone
buildings, stream junctions,
hills, bridges, and railroad
crossings. 
They may be selected
throughout the area of operation. 
By reference to these
points, the subordinate commander
may rapidly and accurately report
his location; or the higher
commander may designate
objectives, boundaries, assembly
areas, phase lines, and so forth,
to his subordinate commanders.

Figure 071-332-5000-24.
Checkpoint

(8) 
Contact points. 
Contact points, shown
graphically by squares with a
staff extending from the bottom
center, are designated at the
units to make physical contact. 
Contact points may also be
used to delineate areas of
responsibility in specific
localities when boundaries are
obviously unsuitable, such as
between elements of a flank guard
(figure 071-332-5000-25).

Figure 071-332-5000-25.
Contact Point

(9) 
Passage points (PP). 
A passage point, shown
similar to a checkpoint with the
letters PP and the number or
letter designation of the passage
point within the symbol, is
designated along the LD or the
FEBA of the unit being passed
through. 
The PPs will be located
where the commander desires
subordinate units to actually
pass.

(10)
Linkup points.  A linkup point should be an easily identifiable point on
the ground and map that is used to
facilitate the joining, connecting,
or reconnecting of elements of a
unit or units. 
They are used when two or
more Army elements are to join each
other, when Army and sister service
elements are to join each other, and
when Army or sister service and
allied elements are to join each
other. 
The linkup is an operation in
itself and is conducted as part of
an airborne or airmobile operation,
an attack to assist in the breakout
of an airborne or airmobile
operation, an attack to assist in
the breakout of an encircled force,
or an attack to join an infiltrating
force. 
The battalion may participate
in a linkup as part of a larger
force, or it may conduct a linkup. 
The symbol for linkup points
is similar to a checkpoint with a
dot in the center. 
A number, the name, or code
name is placed near the symbol in
such a manner as to ensure it is
referring to the symbol (figure 071-332-5000-26).

Figure 071-332-5000-26.
Linkup Point

(11)
Points of departure (PDs).
These normally are shown along the
LD for night attacks. 
They are shown similar to a
checkpoint containing the
abbreviation “PD” and a letter
or number within the symbol. The
point of the arrow is at the bottom
of its location.

1.   Placed registering marks in opposite corners of the
overlay.

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2.   Marked information using standard military symbols.

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3.   Indicated enemy installations, equipment, or
activities with either the color RED
or with double-lined symbols.

—

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4.   Indicated future locations or coordinating detail
with broken-line symbols.

—

—

5.   Placed symbols indicating size on a boundary to
indicate the highest unit sharing the
boundary.

—

—

6.   Extended the axis of advance arrow from the line of
departure to the objective.

—

—

7.   Labeled the route of march arrows with a code name
or unit designation.

—

—

8.   Labeled the MSR and assigned a code name.

—

—

9.   Ensured the center of a unit symbol corresponded to
the coordinates of the unit.

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FM
3-90.2

FM
101-5-1