text: Chapter 1
  lowest tactical echelons, and they create an electromagnetic signature which can either be jammed or used
  for targeting purposes.
  1-52. Analog control measures are hand-drawn on maps or overlays and are used by every echelon.
  Generally, battalion and above echelons use paper maps with overlays as a backup to many of their digital
  systems. Company and below echelons are more likely to use paper maps with overlays containing analog
  control measures as their primary means of command and control. These overlays consist of graphical control
  measures that allow the organization to maintain a common operational picture and continue operations
  within a degraded communications environment.
  Note. FM 3-90 contains numerous figures containing graphic control measures when describing
  offensive, defensive, and enabling operations. For clarity, these figures contain only the major
  applicable graphic control measures. Appendix A contains additional information on each of the
  control measures discussed in FM 3-90. For a complete listing of all control measures see
  FM 1-02.2.
  Terrain Management
  1-53. Units manage terrain to coordinate and synchronize their operations with friendly forces. Terrain
  management is the process of allocating terrain by specifying locations for units and activities to
  deconflict activities that might interfere with each other. For example, an artillery unit is assigned a
  position area for artillery (PAA) to provide indirect fires. The PAA frames for the artillery unit the area for
  executing their fire missions and lets other units know that they need to coordinate with the PAA owner if
  they need to move through that area. Examples of terrain management include but are not limited to—
  * Assigned areas including area of operations, zone, and sector.
  * PAA.
  * Assembly area.
  * Battle position.
  * Route.
  * Lane.
  * Axis of advance.
  1-54. Assigning areas to subordinates is a key operational framework and terrain management consideration
  for headquarters at every echelon. When appropriate units may further subdivide their assigned area into
  assigned areas for their subordinate formations. A higher headquarters remains responsible for any area not
  assigned to a subordinate unit. A unit moving through or delivering effects into another units assigned area
  must coordinate with the assigned unit.
  1-55. The types of assigned areas include area of operations, zone, and sector. While there are numerous
  other control measures that enable terrain management only area of operations, zone, and sector are part of
  the assigned area model. Each assigned area has unique characteristics and employment considerations
  outlined below.
  Area of Operations
  1-56. An area of operations is an operational area defined by a commander for land and maritime forces that
  should be large enough to accomplish their missions and protect their forces (JP 3-0). Units can use an area
  of operations (AO) during offensive, defensive, and stability operations. An AO is defined by boundaries
  that fully enclose the area. An AO is useful when a higher headquarters requires a greater degree of control.
  Units assigned an AO must be capable of performing specific responsibilities. These responsibilities
  include—
  * Terrain management.
  * Information collection, integration, and synchronization.
  * Civil affairs operations.
  * Movement control.