1959 US Army Vietnam War Terrain Intelligence ... - Survival Books

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year. A statement of the total amount of precipitation that
can be expected over a period of time has little significance
in itself, since a 3-inch rainfall means one thing when spread
over 30 days and a totally different thing when concentrated
in 1 day during the 30-day period. The effect of precipitation
on other terrain features, particularly water bodies and
the trafficability of soils, should be described in the written
text.
(4) Winds. Wind data based on climatic research present the
direction, intensities, and duration that can be expected over
a period of time. These data are best expressed graphically
by means of a wind rose or may be referenced to the Weather
Map Scale of Wind Velocity. Wind rose data may be secured
from AWS when specifically required by a commander.
The effect of wind on surface materials and on
waves is described when pertinent (app. V).
(5) Humidity. Exact descriptions of humidity are not usually
necessary, but the effects of humidity on operations is described
when significant. The description should consider
fog conditions and the effect of humidity in reducing the
efficiency of personnel or in creating problems of storage and
maintenance of supplies and equipment.
(6) Clouds. Data based on climatic records signify the approximate
number of days during a specific period that a certain
degree of cloud cover can be expected. Also, there is an indication
as to what time of the day or night certain cloud
coverage can be expected. Related conditions such as storms
and fog are also described when applicable.
(7) Electrical disturbances. This subject is discussed only when
it has an important effect on proposed operations. The type
of disturbance, its period of occurrence and duration, and its
effect on planned operations are described in the written text
when pertinent.
32. Natural and Manmade Features
a. Methods. Methods of indicating natural and manmade features
in a terrain study are discussed in this paragraph.
b. Relief. Relief is described both symbolically and in the text to
highlight significant relief features, but not to repeat the detail of a
topographic map. Relief symbols are usually brown. The general
picture of the relief of an area may be indicated by ridge and stream
lining, which accentuates the major ridges and drainage patterns.
This consists of emphasizing the streams by drawing over them with a
heavy blue pencil and emphasizing ridges with a brown pencil. When
emphasizing ridges, heavy lines are drawn along the topographic
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