This website is not affiliated with the U.S. government or military. All proceeds from the operation of this site are donated to veteran and other charities.

Observation and Fields of Fire, Cover and Concealment,
Obstacles (man made and natural), Key or Decisive Terrain, Avenues of Approach

Observation and Fields of Fire, Cover and Concealment,
Obstacles (man made and natural), Key or Decisive Terrain, Avenues of Approach

Observation and Fields of Fire
Cover and Concealment
Obstacles (man made and natural)
Key or Decisive Terrain
Avenues of Approach



All of these factors must be analyzed in light of

the mission of the unit
the type operation
the level of command
the composition of forces involved
the weapons and equipment expected to be encountered

1. Observation and Fields of Fire

The evaluation of observation and fields of fire allows you to-

Identify potential engagement areas
Identify defensible terrain and weapons system positions.
Identify where maneuvering forces are most vulnerable to observation and fires.


Observation is the ability to see over a particular area to acquire targets.

“Visibility” is weather dependent or is a temporary phenomena. Observation, on the other hand, is terrain dependent and is relatively permanent. Generally, the best observation is obtained from the highest terrain in an area.

Fields of Fire

The area a weapon can cover effectively from a given point
Fires can be of two basic types

Direct fire weapons like machine guns, rifles, and TOW weapon systems which require direct line of sight to their targets.
Indirect fire weapons such as mortars and artillery
Observation and fields of fire are not the same. You may be able to see 25 km, but if all you see are armed with a rifle, then your fields of fire will probably be limited to something like 500 meters.

2. Cover and Concealment


The protection from the effects of weapons fires, direct, indirect, and air to ground.

Certain aspects of the terrain may provide good cover from some fires, while some may provide cover from only one of these types.


Protection from observation, either from the air or from the ground or both.


built up areas

Remember that cover can be used to protect a force from the effects of direct and indirect fires. Also it can, in some cases, be used to protect a force from observation. If this is the case, then the object providing cover is also providing concealment. But cover and concealment do not always equate.

If an attacking force can move forward under concealment, the chances of achieving surprise increase. Concealed and covered approach routes are important to reconnaissance units, dismounted infantry, and insurgent or terrorist forces.

Defending forces seek to defend in an area which offers both concealment and cover to themselves but which does not provide covered approaches for the threat

3. Obstacles

Any natural or manmade terrain feature that stops, impedes, slows, or diverts movement.


buildings, steep slopes, rivers, lakes, forests, deserts, swamps, jungles, cities, minefield, trenches, andmilitary wire obstacles

Things to look for:

Vegetation (tree spacing and trunk diameter).
Surface drainage (stream width, depth, velocity, bank slope, and height).
Surface materials (soil types and conditions that affect mobility).
Surface configuration (slopes that affect mobility).
Obstacles (natural and manmade; consider obstacles to flight as well as ground mobility).
Transportation systems (bridge classifications and road characteristics such as curve,radius, slopes, and width)
Effects of actual or projected weather such as heavy precipitation or snow over.

4. Key or Decisive Terrain

Some terrain feature (natural or manmade) which, if controlled, will give a marked advantage to whoever controls it.
Often selected for use as battle positions or objectives
Echelon of command, mission, enemy, and situation dependent.
To designate terrain as decisive is to recognize that the mission depends on seizing or retaining it.
Key or decisive terrain must be controlled, not necessarily occupied. It may be controlled by either fires or maneuver.


a bridge over an unfordable river which gives access to the opposite shore without requiring an assault crossing.
a level clearing in rough terrain which is the only accessible landing field for airmobile operations
if you identify only one valid avenue of approach to the command’s objective, then the choke points on that avenue will probably become key terrain (compared to a situation where several AAs are available).

5. Avenues of Approach (AoA)

An AoA is an air or ground route of an attacking force of a given size leading to its objective or to key terrain in its path.

Important Information: We strive to provide information on this website that is accurate, complete and timely, but we make no guarantees about the information, the selection of schools, school accreditation status, the availability of or eligibility for financial aid, employment opportunities or education or salary outcomes. Visit here for important information on these topics.