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# Military

## RECONNAISSANCE OVERLAYS, SYMBOLS, AND FORMULAS

This appendix provides leaders the necessary data to use overlays, symbols, and formulas in their reconnaissance efforts.

### A-1. SYMBOLS

Figure A-1 outlines a variety of symbols that soldiers can use to illustrate reconnaissance data on their overlays. Figure A-2, shows an example of how these graphics are used in the overlay. Figure A-3, shows symbols for various materials, facilities, equipment, and services. (These graphics are adapted from information provided in FM 5-170.) Figure A-1.  Reconnaissance overlay symbols. Figure A-1.  Reconnaissance overlay symbols (continued). Figure A-1.  Reconnaissance overlay symbols (continued). Figure A-1.  Reconnaissance overlay symbols (continued). Figure A-1.  Reconnaissance overlay symbols (continued). Figure A-2.  Example of overlay graphics. Figure A-3.  Material, facility, equipment, and service symbols.

### A-2. FORMULAS

This paragraph covers formulas for the reconnaissance platoon to use in water crossing operations and in determining the slope of a road or other piece of terrain. The information is adapted from FM 5-34.

a.   Formulas for Water Obstacles.

(1)   Width. Scouts can measure the width of a river or stream using one of several available methods:

• Stretching a string or measuring tape across the river or stream.
• Using a map scale.
• Using a compass and the basic mathematical computation illustrated in Figure A-4.

(2)   Velocity. Scouts can measure the velocity of the current of a river or stream using the procedures shown in Figure A-5.

b.   Slope Computation. To determine the slope of a piece of ground, whether it is an established roadway or a cross-country route, soldiers use a clinometer. If a clinometer is not available, they use the slope computation formula, which requires using one of the following methods to determine horizontal and vertical distances (Figure A-6):

• Compute horizontal and vertical distances based on the map scale and contour differences for the road or terrain.
• Estimate horizontal and vertical distances using pacing and eyesight (hasty method). Figure A-4.  Measuring stream width with a compass. Figure A-5.  Measuring stream velocity. ### A-3. CONVERSION TABLES

Soldiers can use the following tables for converting English measurements to their metric equivalents. Table A-1 lists conversions for common distance measurements (inches to centimeters; feet to meters; yards to meters; miles to kilometers). Table A-2, shows conversions of miles per hour to kilometers per hour. Table A-3, refers to field-expedient antenna lengths. Table A-1. English to metric distance measurement conversions. Table A-2. Miles per hour to kilometers per hour conversions. Table A-3. Operating frequency and wire element length.