Part One
  Map Reading


  Reading Topographical Maps Introduction 1. HOME

  Topographical Maps - Definition, Purpose and Categories 2. Maps

  Information in the margins of an army map 3. Marginal Information    and Symbols

  Latitude, Longitude and Other Methods to Locate Points on Topographic Maps 4. Grids

  Translating Distance on a Topographic Map to Distance on the Ground 5. Scale and Distance

  Grid North, Azimuth, Declination And Other Concepts Used To Find Direction With Topographic Maps 6. Direction

  Overlays - Used Primarily In Army Map Reading 7. Overlays

  Aerial Photographs - Supplements And Substitutes For Topographic Maps 8. Aerial Photographs

 Part Two
  Land Navigation


  Using Compass, GPS, Sun, Shadows, and Stars in Land Navigation 9. Navigation Equipment    and Methods

  Reading The Shape Of The Land In Topographic Maps 10. Elevation and Relief

  Orienting and Navigating With Topographic Maps 11. Terrain Association

  Mounted Land Navigating With Motorized Vehicles 12. Mounted Land    Navigation

  Land Navigation In Different Types of Terrain 13. Navigation in    Different Types of    Terrain



  Sketching Topographic Maps A. Field Sketching

  Folding Topographic Maps B. Map Folding     Techniques

  Units of Measure and Conversion Factors Used in Reading Topographic Maps C. Units of Measure and      Conversion Factors

  Units of Measure and Conversion Factors Used in Reading Topographic Maps D. Joint Operations      Graphics

  US Army Training Material for Map Reading and Land Navigation E. Exportable Training      Material

  Orienteering F. Orienteering

  US Army M2 Compass G. M2 Compass

  Additional Aids such as Night Vision Goggles and Global Positioning System or GPS H. Additional Aids      (GPS, Night Vision)

  Global Positioning System -  GPS J. Global Positioning      System - GPs

 

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9-4. USING A COMPASS

Magnetic azimuths are determined with the use of magnetic instruments, such as lensatic and M2 compasses. The techniques employed when using the lensatic compass are as follows:

a.   Using the Centerhold Technique. First, open the compass to its fullest so that the cover forms a straightedge with the base. Move the lens (rear sight) to the rearmost position, allowing the dial to float freely. Next, place your thumb through the thumb loop, form a steady base with your third and fourth fingers, and extend your index finger along the side of the compass. Place the thumb of the other hand between the lens (rear sight) and the bezel ring; extend the index finger along the remaining side of the compass, and the remaining fingers around the fingers of the other hand. Pull your elbows firmly into your sides; this will place the compass between your chin and your belt. To measure an azimuth, simply turn your entire body toward the object, pointing the compass cover directly at the object. Once you are pointing at the object, look down and read the azimuth from beneath the fixed black index line (Figure 9-2). This preferred method offers the following advantages over the sighting technique:

(1)   It is faster and easier to use.

(2)   It can be used under all conditions of visibility.

(3)   It can be used when navigating over any type of terrain.

(4)   It can be used without putting down the rifle; however, the rifle must be slung well back over either shoulder.

(5)   It can be used without removing eyeglasses.

Figure 9-2. Centerhold technique.

Figure 9-2. Centerhold technique.

b.   Using the Compass-to-Cheek Technique. Fold the cover of the compass containing the sighting wire to a vertical position; then fold the rear sight slightly forward. Look through the rear-sight slot and align the front-sight hairline with the desired object in the distance. Then glance down at the dial through the eye lens to read the azimuth (Figure 9-3).

NOTE: The compass-to-cheek technique is used almost exclusively for sighting, and it is the best technique for this purpose.

Figure 9-3. Compass-to-cheek technique.

Figure 9-3. Compass-to-cheek technique.

c.   Presetting a Compass and Following an Azimuth. Although different models of the lensatic compass vary somewhat in the details of their use, the principles are the same.

(1)   During daylight hours or with a light source:

(a)   Hold the compass level in the palm of the hand.

(b)   Rotate it until the desired azimuth falls under the fixed black index line (for example, 320°), maintaining the azimuth as prescribed (Figure 9-4).

Figure 9-4. Compass preset at 320 degrees.

Figure 9-4. Compass preset at 320 degrees.

(c)   Turn the bezel ring until the luminous line is aligned with the north-seeking arrow. Once the alignment is obtained, the compass is preset.

(d)   To follow an azimuth, assume the centerhold technique and turn your body until the north-seeking arrow is aligned with the luminous line. Then proceed forward in the direction of the front cover's sighting wire, which is aligned with the fixed black index line that contains the desired azimuth.

(2)   During limited visibility, an azimuth may be set on the compass by the click method. Remember that the bezel ring contains 3° intervals (clicks).

(a)   Rotate the bezel ring until the luminous line is over the fixed black index line.

(b)   Find the desired azimuth and divide it by three. The result is the number of clicks that you have to rotate the bezel ring.

(c)   Count the desired number of clicks. If the desired azimuth is smaller than 180°, the number of clicks on the bezel ring should be counted in a counterclockwise direction. For example, the desired azimuth is 51°. Desired azimuth is 51°¸ 3 = 17 clicks counterclockwise. If the desired azimuth is larger than 180°, subtract the number of degrees from 360° and divide by 3 to obtain the number of clicks. Count them in a clockwise direction. For example, the desired azimuth is 330°; 360°-330° = 30 ¸ 3 = 10 clicks clockwise.

(d)   With the compass preset as described above, assume a centerhold technique and rotate your body until the north-seeking arrow is aligned with the luminous line on the bezel. Then proceed forward in the direction of the front cover's luminous dots, which are aligned with the fixed black index line containing the azimuth.

(e)   When the compass is to be used in darkness, an initial azimuth should be set while light is still available, if possible. With the initial azimuth as a base, any other azimuth that is a multiple of three can be established through the use of the clicking feature of the bezel ring.

NOTE: Sometimes the desired azimuth is not exactly divisible by three, causing an option of rounding up or rounding down. If the azimuth is rounded up, this causes an increase in the value of the azimuth, and the object is to be found on the left. If the azimuth is rounded down, this causes a decrease in the value of the azimuth, and the object is to be found on the right.

d.   Bypassing an Obstacle. To bypass enemy positions or obstacles and still stay oriented, detour around the obstacle by moving at right angles for specified distances.

(1)   For example, while moving on an azimuth of 90° change your azimuth to 180° and travel for 100 meters. Change your azimuth to 90°and travel for 150 meters. Change your azimuth to 360°and travel for 100 meters. Then, change your azimuth to 90°and you are back on your original azimuth line (Figure 9-5).

Figure 9-5. Bypassing an obstacle.

Figure 9-5. Bypassing an obstacle.

(2)   Bypassing an unexpected obstacle at night is a fairly simple matter. To make a 90° turn to the right, hold the compass in the centerhold technique; turn until the center of the luminous letter E is under the luminous line (do not move the bezel ring). To make a 90° turn to the left, turn until the center of the luminous letter W is under the luminous line. This does not require changing the compass setting (bezel ring), and it ensures accurate 90° turns.

e.   Offset. A deliberate offset is a planned magnetic deviation to the right or left of an azimuth to an objective. Use it when the objective is located along or in the vicinity of a linear feature such as a road or stream. Because of errors in the compass or in map reading, the linear feature may be reached without knowing whether the objective lies to the right or left. A deliberate offset by a known number of degrees in a known direction compensates for possible errors and ensures that upon reaching the linear feature, the user knows whether to go right or left to reach the objective. Ten degrees is an adequate offset for most tactical uses. Each degree offset moves the course about 18 meters to the right or left for each 1,000 meters traveled. For example, in Figure 9-6, the number of degrees offset is 10. If the distance traveled to "x" in 1,000 meters, then "x" is located about 180 meters to the right of the objective.

Figure 9-6. Deliberate offset to the objective.

Figure 9-6. Deliberate offset to the objective.


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Books

Map Reading and Land Navigation Buy the book this website is based on: Map Reading and Land Navigation

This website is based on the US Army Field Manual: "Map Reading and Land Navigation" Buy a copy from Amazon.com to take with you out in the field.

 

Book Review - Be Expert with Map and Compass

One of the best ways to learn and become proficient in any subject is to find a way to make a game or sport of it. That's exactly what orienteering does! Orienteering began to develop almost 100 years ago in the Scandinavian countries as a fun and effective method for military training in land navigation. Bjorn Kjellstrom was closely involved with the early development of orienteering, and he is the person who introduced the sport to North America. He, along with his brother Alvar, and a friend named Gunnar Tillander, invented the modern orienteering compass. They manufactured and marketed it as the Silva Protractor compass. This compass, along with Bjorn's book Be Expert with Map and Compass, made it much easier for anyone to learn how to use a map and compass.

This book has become the most widely read classic on the subject of map reading, compass use, and orienteering. Over 500,000 copies have been sold in the english language editions alone. There have been very successful editions published in French, Italian, and other languages as well. It is a short (just over 200 pages), easy to read, enjoyable book that can help you to have fun while you learn the subject quickly and effectively.

The book is organized into four main parts, plus a short, useful introduction. Part 1 covers having fun with maps alone. Then, Part 2 covers having fun with a compass alone. Part 3 puts it together and shows you how to have fun with a map and compass together. This section also introduces the game or sport of orienteering. Part 4 covers competitive orienteering for those who would like to compete with others in the sport.

A reproduction of a segment of an actual topographic map is included as a fold-out in the back of the book. It is used together with the "how-to" instructions the book provides. For example, one of the exercises in Part 3 is an imaginary orienteering "hike" that uses the sample map.

If you would like to have one of the best books available on map reading and using a compass, Be Expert with Map and Compass is hard to beat. You can buy a copy from Amazon.com today.

Read a book review of Agincourt

Boat Navigation For The Rest of Us
  Boat Navigation For The Rest of Us

Basic Coastal Navigation
  Basic Coastal Navigation