Air Fronts: FM 21-26, Advanced Map and Aerial Photograph Reading - Section 3.

SECTION III: CONVENTIONAL SIGNS AND MILITARY SYMBOLS

6. CONVENTIONAL SIGNS. a. Signs. Conventional signs are used on maps to indicate objects on the ground. Usually, they are simple drawings recognizable as the objects they represent. The meaning of some signs, however, is not obvious and must be learned. Complete lists of conventional signs authorized for use on United States military maps are found in FM 21-30; foreign conventional signs are shown in FM 30-22. When foreign maps are adapted and issued to troops conventional signs which differ from signs used on United States maps are explained in the map margin.

b. Colors. Colors are used on some maps to help identify terrain features. These colors are black, blue, brown, green, and red:

Black for works of man.

Blue for water and swamps.

Brown for contours, cuts and fills, and some cultivated fields on large-scale maps.

Green for woods and other vegetation.

Red for certain good roads.

7. MILITARY SYMBOLS. Military symbols have been developed to represent various types of military organizations, activities, and installations. These symbols are used to indicate size and identity of various units and installations, type and location of supporting weapons, and necessary lines and boundaries for an operation. Friendly installations are usually shown in blue, enemy installations in red. FM 21-30 lists the standard military symbols.