racteristics of the Theater of Operations.

The characteristics of the theater of operations exert an influence,
always important, sometimes paramount, upon the possibility of
attaining the objective, and upon the strategical and tactical
operations that may be employed.

At this point in his estimate the commander utilizes his charts,
intelligence reports, and hydrographic publications to make a factual
study of the theater. This study is not for the purpose, at this time,
of drawing any conclusions as to possible courses of action, but to
furnish data which will assist in consideration of later sections of
the estimate. The study may be made under several important headings,
as follows:

(a) Hydrography. A study of the hydrography will determine the depth
of water, the existence of shoals, the presence of unusual currents,
the rise and fall of the tides, the availability of channels, and
other pertinent features. These are recorded for later use.

Shallow water may permit mining or may prevent the operation of
submarines. On the other hand, the ability to mine in shallow water
may be curtailed by strong currents or by the rise and fall of the
tide. Again, the depth of water, the strength of currents, and the
range of the tide may determine the feasibility of netting the
entrance to a port or base. In a tactical action, advantage may be
taken of shoals to limit the freedom of action of the enemy, without,
however, interfering with that of one's own forces.

(b) Topography. The topography of the area is also frequently of
interest to the naval commander. In actions close to the shore, the
character of the coast may play an important role. A high bluff,
combined with considerations as to light, may create a very definite
advantage or disadvantage in a naval tactical situation.

Topography may be a most important consideration in determining what
bases are to be used. The commander makes note of the topography of
the various possible bases; later in his estimate, the natural
features lending assistance to the defense of the various sites may
play an important part in the selection of bases.

The use of channels may depend upon the topography of the bordering
land. Questions arise as to whether such land can be seized and held,
or, if in friendly hands, whether it can afford adequate protection to
the channel.

In any landing operation, the topography of the area to be occupied
may be the controlling factor.

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