text: FM 7-100.1________________________________________________________________________________
  ORGANIZING THE OPERATIONAL BATTLEFIELD
  2-62. The OPFOR organizes the battlefield in such a way that it can rapidly
  transition between offensive and defensive operations and between linear
  and nonlinear operations. This flexibility can help the OPFOR adapt and
  change the nature of the conflict to something for which the enemy is not
  prepared.
  Battlefield Geometry
  2-63. The OPFOR recognizes the complexity of the modern battlefield. This
  will often lead to situations where part of the OPFOR may be able to effec-
  tively operate in a linear fashion, while other parts may be able to (or need
  to) conduct nonlinear operations. The OPFOR’s understanding of what makes
  a battlefield linear or nonlinear is based on general military theory accepted
  by the armed forces of many countries. Battlefield geometry can be described
  in two dimensions: the relationship of units to each other, the enemy, and
  their support base; and the expected effects of that relationship.
  2-64. Linear Operations. Some military operations develop along a secure
  line from a base toward a geographically-based objective. These linear opera-
  tions are characterized by an easily definable front and rear across the entire
  force. Orientation of the bulk of the force is in one general direction, defined
  as the front, normally facing the enemy and/or the objective. (See Figure 2-
  10.) During linear operations, the flanks of units are normally protected by
  other units, natural terrain features, or manmade obstacles.
  Rear Front
  X
  Base
  Objective
  X
  Enemy
  Figure 2-10. Linear Operations