Figure 2-14. Special grid sheet map

TM 9-6920-361-13&P

(2) The forward observer will be required to

example, FROM REFERENCE POINT THREE, GO

locate all targets using the shift from a known point

RIGHT 35 MILS AND DOWN FROM THE SKYLINE

method until survey has located his position and the OP

ZERO MILS. THIS WILL PLACE YOU ON A SELF-

is plotted on the firing chart. At that time, the forward

PROPELLED GUN.

observer can send polar coordinates in his call for fire.

(3) Survey should start at the earliest

opportunity and, if possible, be completed prior to the

start of the service practice, precluding the need for an

OF chart. The survey party can provide the forward

observer with a crude map by drawing 500-meter grid

lines between the 1,000-meter lines on a 1:25,000 grid

sheet. This creates a map of 1:50,000 scale. Each grid

line is then labeled with its 100-meter (1,000 decimeters)

designation. The grid sheet will then become a map with

Figure 2-15. Firing point marker

Figure 2-14. Special grid sheet map

(4) Critical points (buildings, road junctions,

watertowers, targets, OPs, FPs, etc.) can be plotted on

the grid sheet. These critical points should be located to

the nearest 0.1 meter with an accuracy of 1 in 500. This

information will be required to construct the special map.

c. Survey Requirements.

(1) A type of firing point marker which could

be used on a permanent range is shown in figure 2-15.

Figure 2-16. Permanent reference point

The marker is a metal rod with a flat piece of metal 12

inches by 6 inches welded to it. A 3-foot piece of pipe

driven into the ground serves as a holder for the marker.

Reference points in the impact area are used by the

officer in charge to identify targets to the observer. For

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