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Map Orientation!
Map/Compass/Ground Orientation!
A needed preliminary step to map/ground association is to orient the map with the lay of the land. After orientation, if you plot your location on the map, and while doing it see a hill top 2000 yards to the northwest, you should be able to look up and see that same hill top to your right-front at 2000 yards.
The method used to orient the map with the ground depends on what you’re doing. If all you want is a quick analysis, determine north (compass) and point the top of your map in that direction, and map is generally oriented. But, if you’re intention is to determine/plot directions or azimuths on the map and accuracy is critical, the method used should be exact, deliberate and allow no errors:
- Place the map on a flat surface;
- Open compass and place it (straightedge) parallel with a North/South grid-line.
- Keeping the compass aligned, as directed above, carefully rotate the map/compass (together) until the magnetic arrow is below the fixed black index line of the compass (almost oriented);
- To further compensate for the small Grid/Magnetic (GM) angle change, rotate map and compass in the direction of the magnetic arrow in the declination diagram. Whether movement is right or left, rotate the map/compass that small amount (degree/mils) indicated by the G/M angle. The number of degrees/mils of rotation will be reflected under the fixed index line of the compass.
The map and compass are now oriented in accordance with map’s Declination Diagram.
Does it look that way on the map?
Map/Ground Comparison!
We have already established that the top of the map always reflects North, map’s right: East, bottom: South, and the left (as you look at it) would be West.
Based on the vast information contained in the map, including the many different types of terrain and other features; coupled with your Map Reading/ Land Navigation knowledge and skills, it is fairly simple to start visualizing how the land/terrain must appear in relation to your position on the map.
This, couple with your knowledge of the compass and various land navigational techniques, will assist in your map study and terrain/map association. It should culminate with committed movement on the ground. The key to its success is in preparation; it must be as-slow-as necessary, methodical, and very deliberate.
Pace Count!
You do the pace-count; I'll keep us on course!
Determining distance is extremely difficult and the most common source for error in cross-country land navigation.Establishing an accurate pace-count is very important. A pace is equal to one normal step. You must determine how many paces it takes you to walk 100 meters/yards. The average pace for an adult male is 30 inches in length. However, the following, sustained conditions will affect that pace and must be considered/accounted for:
- Pace lengthens on a down-slope and shortens on an up-grade;
- Head-winds shorten the pace – tail-wind will increase the pace;
- Sand, gravel, mud, snow, and similar conditions tend to shorten the pace;
- Falling snow, rain, or ice cause the pace to be reduced;
- Excess clothing and boots with poor traction will affect the pace length;
- Poor visibility such as fog, rain, or darkness will shorten your pace.
In the absence of electronic devices, establish the minimum of a 100 meter confirmation course and validate your pace-count. Terrain and environmental conditions should be duplicated as-much-as possible.
Extension for the Memory!
Keep It Simple!
If your game is serious land navigation, there will be times when all you have that is useful to navigate with is an azimuth, your compass, the straight-line distance in yards/meters to where you‘re going, and your two feet to get you there.
For me, the difficulty is not following the compass reading but rather keeping track of the distance traveled. When you get 10,000 meters into a 20,000 meter leg, things have a tendency to start running together – was that 9,500 or 9,600 meters. Your memory will play tricks on you if you don’t have a device, system, or way of keeping track of what you’ve done.
Ideally, you’ll have a trekking buddy that will do that for you, and all you’ll have to do is stay on course. A simple thing I’ve done, to keep track of the distance traveled, was to use a couple foot-long, 1/4 inch ropes/cords. Each time I walked 100 meters, I would tie a knot in one of the ropes. When I had ten knots in the rope, I would tie one knot in the other rope. You would continue this process until the desired distance has been traveled. What is critical about this is that you must know how many steps it takes for you to walk 100 meters.
Compass to Cheek Method!
Sighting the Compass!
The Compass to Cheek method of holding a Lensatic Compass is used almost exclusively for sighting. Obviously, if using, there must be enough light to see the far distant aiming point/object. The following sequential steps can be used to place the compass into operation:
- Open the Lensatic Compass cover (w/sighting wire) to a vertical position.
- Pull up the sighting lens slightly, place thumb through the thumb loop and provide a steady base by forming a fist around the thumb with four remaining fingers.
- Take second hand and grasp supporting hand and depict in diagram above.
- Lift compass to cheek and look through the rear-sight slot and align the front-sight hairline with the far distant aiming point/object.
- Glance down at the dial through the eye lens and read the direction/azimuth in either degrees or mils.
Remember, the direction/azimuth obtained with a Lensatic Compass is a magnetic reading and must be converted to a grid direction/azimuth before plotting on a map.
Using a Lensatic Compass!
Centerhold Position!
There are several Lensatic Compass holding techniques; however, in the interest of expedience, this posting will cover the most common and generally preferred method. The Centerhold Technique is assumed by:
- Open the compass (fullest extent).
- Move rear sight to the upright position (unlocks floating dial).
- Place thumb through the thumb loop; form a steady base with third and fourth fingers; extend index finger along side the compass; place other thumb between the rear sight and the compass dial; extend the index finger along the other side of the compass and remaining fingers around the other hand; pull your elbows into your side and turn your body in the direction of the target/object for azimuth reading/determination.
To determine the azimuth, once the compass is pointing at the target, look down and read the azimuth from beneath the fixed black index line. Remember, this is a magnetic reading and must be converted to Grid before plotting on a map.
Compass Handling!
Magnetic, Lensatic Compass!
A Lensatic Compass does not require a large amount of maintenance. However, prior to use, it should be inspected for operability, insuring: 1. The sight wire is serviceable and in place; 2. Neither the sight glass or crystal face is broken; 3. The floating dial is not stuck and functions freely/properly.
The compass should be checked periodically to insure it delivers a correct reading. This is done by comparing the applicable compass direction/azimuth reading with the known surveyed data (direction/azimuth) to the same aiming point. If the compass is off more than 3 degrees, it shouldn’t be used. When not in use, the eye lens of the Lensatic Compass should be in the down position, locking/securing the floating dial and also providing protection to the crystal face/rear sight.
Metal objects and electrical sources will adversely affect a magnetic compass reading. Therefore, to preclude this from happening, the following minimum separation distances must be followed:
- Power Lines – 55 meters;
- Vehicles – 18 meters;
- Telephone or Barbed Wire – 10 meters;
- Small Metal Objects (rifle/pistol) – ½ meter.
The Compass!
Convenient/Accurate/Reliable
As with the Topographical Map, a compass is an essential component to Land Navigation. There are many makes, models, and styles; however, for the sake of my knowledge and verifiable dependability, I would suggest a Lensatic Compass.
This compass should be characterized by illumines markings so it can be used during the hours of limited visibility. To further facilitate easy use, it should have a magnifying lens and a dial that is graduated in both mils and degrees. There are both reputable US Military and lesser dependable but still useable civilian Lensatic Compasses.
The compass pictured above is used, on a daily basis, by our Military Forces. If procured from a reputable retail outlet and if advertised as an authentic“US Military Lensatic Compass”, you can be assured that it would give you years of good/dependable service.
Minor Terrain Feature – Cliff!
Map/Terrain Association!
A Cliff is a vertical or near vertical feature. It is considered to be an abrupt change in the land structure. When the land is so steep that the contour lines converge into one, the last contour line will have tick marks pointing towards low-ground.
But, cliffs are also shown with continuous lines very close together and in some cases actually touching each other. This of course also indicates a very steep-to-vertical up/down-grade.
As stated previously, map reading proficiency is based (to a large extent) on a person’s ability to associate what they’ve seen on a map with what is found on the ground. This is such a degradable skill and must be practiced frequently.
Minor Terrain Feature – Draw!
Map/Terrain Association!
A draw is considered to be a Minor Terrain Feature. It is a less developed stream course than a valley and has little -to-no level ground or maneuver within its confines.
If you’re standing in a draw, the ground slopes upward in three directions and downward in the other direction. It might be considered as the initial formation of a valley. The contour lines depicting a draw are “U” or “V” shaped, with the closed portion of the “U” or “V” shape pointing up-hill or towards the the high-ground.
Critical to a person’s map reading proficiency is their ability to associate what they see on the map with what they find on the ground.
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