Navigation 101 by TireIron

There are many old techniques for finding north without a compass and using that information to get around, but as the old grizzled Master Sergeant that taught me (tire iron) map and compass skills confided in me – “all of that is fancy horse$#!&, if you don’t have a *&#$ map and a #!&% compass – you are mother%$#@& lost!” He is correct. All of those other primitive techniques work only under the best of circumstances – and only if one has the luxury of time. Once Murphy rears his ugly head – they all fail except a map and compass. I mean think about it – if you need to find north at night – without a compass – they only way is to find the north start. Well guess what – when you need the find the north star – Murphy will ensure that there is heavy overcast skies – so you can’t see the stars! The moral of the story is: ALWAYS HAVE A COMPASS!

I. Maps
A. There are basically two types of maps

1. Planemetric (flat – no contour to show elevation – most road maps are of this type)
2. Topographic (has contour lines to show elevation – this is the type of map you want to use

B. Maps provide us with the 5 D’s

1. Description
a. name of map area
b. location – relation of other maps in the area
c. dates of survey or field checks
d. things change – floods, dams, reservoirs, roads, bldgs, trails

2. Details (Map Symbols)
a. Black – man made
b. Blue – water
c. Green – vegetation
d. Brown – elevation

3. Direction
a. North is always on top

4. Distances (Scales)
a. 1:24,000 1” = 2,000 feet
b. 1:50,000 1” = 4,166 feet (most military maps)
c. 1:62,500 1” = 1 mile (5,280 feet)
d. 1:250,000 1” = 4 miles

5. Designations
a. Declination Diagram

C. Contour Maps
1. Contour lines indicate elevation changes
a. See handout #1

II. Compass

A. Parts of the compass
1. Direction of travel arrow (with luminous dot)
2. Protractor (Bezel Ring)
3. Orienting Arrow (“non-moving” arrow in or on ring)
4. North Seeking Arrow (with luminous dot)
5. Scales (on side)
6. Lanyard (dummy cord)

B. Map and Compass Theory
1. See handout #2

C. Map Reconnaissance

1. MUST be done beforehand

2. Follow contour lines – less energy expenditure, but remain in the military crest area (below the top of the ridge by 1/3)

3. Watch for danger areas
a. Water (draws people)
b. Roads
c. Trails
d. Buildings (dogs are always present)
e. Swamps/deserts/cliffs/etc.

4. Intentional Offsets can help find one’s target
a. See handout #3
Intentional Offset is used so that you KNOW when you hit the road (or stream/trail/clearing/etc.) - you turn right (or left) to hit the target. NO ONE can walk in a straight line - especially over distance - so if you tried to go on the "true" azimuth - when you hit the road - you wouldn't know if you are to the right or left of the target. By using "Intentional Offset" - you KNOW that you will hit the road to the right (or left) of the target.


[b]III. Declination [b/](My personal definition of this means that your compass doesn’t really point North)
A. To understand declination you must first realize that there are two North Poles. There is a True Geographic North Pole at the top of the world, and a Magnetic North Pole which is about 800 miles south of True North Pole. A magnetic compass always points toward the Magnetic North Pole. Maps are oriented to the True North Pole. The angular difference between True North Pole and Magnetic North is called declination. Declination varies from 0 to 30 degrees in most populated regions of the world. These declination values usually change slightly over time, as the earths plates shift. The actual value of declination and its annual rate of change for your area will usually be shown on your map. This will be expressed as either a Easterly or Westerly declination, depending on your location. (Easterly Declination is when the smaller magnetic north arrow is “east” or to the right of the longer True North Arrow on the declination diagram. Westerly Declination is when the smaller magnetic north arrow is “west” or to the left of the longer True North Arrow on the declination diagram.)
B. Most of Texas up through Montana will have VERY little declination – so little that in many cases one need not worry about it. However, in the Northwest (Seattle) the declination is around 20 degrees easterly – 20 degrees is quite a lot and MUST be compensated for! In my AO the declination is around 15 degrees easterly – and even this must be accounted for. In the Northeast (Maine) the declination is 20 degrees westerly. You local map will have a declination diagram that will tell you exactly what the effect (if any) declination has in your AO.
C. Declination changes EVERY YEAR due to gradual shifts in the continents and the liquid core under the plates.
D. A declination diagram looks like this:
This particular declination diagram shows 15.8 degrees EASTERLY.
E. Keys to remember when using declination when going from a map to a compass are:
1. EAST IS LEAST; subtract the declination value (This refers to the relationship of the True North line to the Magnetic North line – NOT your geographical location!)
2. WEST IS BEST; add the declination vale
a. Problem: if you are in North Carolina, and the declination value is 7 degrees westerly, and the map direction is 150 degrees, you would _________ 7 degrees _______ 150 degrees to the real azimuth (heading) of _______ degrees.

b. Problem: if you are in Washington state, and the map direction is 300 degrees, and the declination value is 24 degrees easterly, you would ______ the 24 degrees ___ the 300 degrees to get your real azimuth of ______ degrees.

3. “Silva Ranger” and “Suunto Professional” model compasses allow one to mechanically adjust the declination so one does not have to do the above calculations in the field. This is one of the problems with the military lensatic compass – these calculations must be done EVERY TIME one stops for a map study. Keep in mind – with the above ‘adages’ of East is least and West is best works ONLY when going from the map to the compass. When one is working with a USGI lensatic (or other compass that doesn’t allow declination adjustment) that the OPPOSITE must be done when going from the Compass reading to the map. BOTTOM LINE – map and compass work are MUCH easier when one only has to perform the adjustment ONCE (Silva Ranger) than having to do these calcs when one is tired, wet, cold and hungry.
F. Avoid ‘gun barrel’ or ‘belt buckle’ declination
1. Example: 1st Lt taking a map reading with map and compass on the hood of a Jeep.
a. Gun barrels in close proximity to compasses can also induce error.
b. To avoid this – lay the compass on the ground, and approach the compass slowly to see if the needle moves when you get close. If it does, by the process of elimination find out what it is on your body that is causing this.

IV. Land Navigation

A. Hold the compass in a way that insures reliability

B. Orient the compass and your body at the same time
1. After checking the azimuth, look in the direction of the azimuth (or use the sighting cabability of the compass if it has one, i.e. Silva Ranger/USGI Lensatic/Suunto Prof.) and find a prominent stationary landmark.
2. Put the compass away (ENSURE IT HAS BEEN DUMMY CORDED TO YOUR ‘1st LINE’ GEAR – I dummy cord mine to my cammie top though a button hole)
3. Walk to the landmark
4. Then repeat steps 1 -3 above

C. For obstacles that one must or wants to avoid, the “box” method is the best one
1. see handout #5
2. Note that “legs” B and D must be the same distance
a. Count the paces (every time left – or right – foot hits the ground)
b. Make sure that the exact pace count is used for both ‘B’ and ‘D’
1. An easy way to go 90 degrees without having to change the compass heading is:
(a) Turn the whole compass 90 degrees to the right
(B) Then turn you body 90 degrees to the right
Do the opposite (use left turns) to get back on course and so on for leg “D”

D. Resection
1. By “shooting” an azimuth at two prominent points, perferrably at 10 o’clock and 2 o’clock on the compass, and calculating the “back azimuth”, one can locate ones exact position on a map
2. See diagram #6
a. When going from “ground” to “map” the opposite declination math must be done – remember that when going from map to ground, “east is least” and “west is best” – so when going from ground to map – one must add the easterly declination and subtract the westerly declination value OR you may not be anywhere NEAR what your resection shows where you are. (Of course if you have an adjusted Silva Ranger you don’t have to worry about doing the math).

E. Map Plotting
1. When reading the coordinates on the map, one must read the vertical lines first – then the horizontal lines. (Remember – I am vertical – standing up – NOW and I will be horizontal – sleeping – LATER.)
2. See handout #7


V. Map care and usage
A. If possible – laminate your maps to weather proof them
B. If lamination is not possible – then a “zip-lock” bag works OK
C. Try to leave the map folded the way it was when you bought it
D. NEVER write on a map – if you loose your map it can compromise your mission

VI. Thoughts on GPS
A. They are a TREMENDOUS aid in verifying the information the map and compass gives
B. They are MUCH more accurate than a map and compass
C. They work in “line of sight” principle – so may not work well in thick forest/jungle/buildings/vehicles
D. They operate off of batteries, so care must be taken to ensure enough supply

My personal opinion is that one should ONLY use a GPS after one has proven to oneself (mastered) that one has the necessary skills of using a map and compass to navigate. This can only be proven by using a map and compass to navigate with MANY TIMES in the dark, i.e. at night. The darker and cloudier - the better. When one can navigate at night with a map and compass in unfamiliar terrain, then one’s skills are ‘up to par’ and THEN one can integrate the GPS into one’s toolbox – but not before.

So – grab a map and compass and TRAIN!!