7-84. Isolated persons must be able to estimate distance from an object to themselves. One way this can be done is by looking at trees. If they can see individual tree branches, they can estimate that they are about 0 to 0.6 mile away from that landmark. Individual trees are about 1 to 3 kilometers away. If isolated persons view the trees as a sort of shag-carpet look, the landmark would be about 3 to 5 kilometers away. A smooth looking carpet appearance is about 5 to 7 kilometers away. A bluish tint or haze in the distance indicates the landmark is about 7 to 10 kilometers away.
7-85. Darkness presents its own characteristics for land navigation because of limited or no visibility. However, the techniques and principles are the same as those used for day navigation. The success in nighttime land navigation depends on rehearsals during the planning phase before the movement, such as detailed analysis of the map to determine the type of terrain in which the navigation is going to take place, and the predetermination of azimuths and distances. Night vision devices can greatly enhance night navigation for the isolated person.
7-86. Night movements are considerably slower than day movements, but METT-TC may require movement during darkness. Pace counts increase during darkness, map checks will take longer, accountability is more difficult. The use of flashlights is not recommended. If an artificial light source is used ensure it is pointed straight down, during a map check it is advisable to cover yourself with a poncho or other material. Noise tends to carry at night and movement through a highly vegetated area may produce more noise than during daylight. In this case it is advisable to alter the route to stay well away from any danger areas or cease movement altogether.
7-87. Navigation using the stars is recommended in some areas. The four cardinal directions can also be obtained at night using the same technique described for the shadow-tip method—just use the moon instead of the sun. In this case, the moon must be bright enough to cast a shadow.
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