1. To find your position using 2 or 3 known points:
This is called triangulation. OK, so you might not know your position exactly, but you do know enough to be able to recognize 2 or 3 landmarks. Triangulation allows you to pinpoint your position.
Navigation is not about finding yourself after you are lost (although that’s what happens sometimes); navigation is about keeping track of your position as you move away from a known point. As you move you have to remain cognizant of the terrain you are leaving, of the terrain you are passing, and of the terrain that is coming up.
Landmarks that are used for triangulation (or for any aspect of navigation) can be anything that you recognize as being on the map. Classically these are hill tops, but you can use the intersection of two roads, a facility such as a power grid sub-station, the abrupt edge of a ridge, the edge of an island, the bend in a trail, anything that you can recognize as being on the map and that you can see.
It is night and you have been wandering in the hills denoted by the big circle. You are on a ridge but not sure which one as denoted by the two small circles. You shoot a bearing to the highest silhouette to the west, which you correlated to the highest hill on your map, you get 255°, and draw that line in blue. You see a car’s headlights make a turn onto Lee Canyon Rd. You shoot a bearing to the intersection, you get 75°, and you draw that line in red. Whoa! 255° and 75° are the same line. They are reciprocal headings, 180° different, however you are on the highest ground there is between yourself and the intersection at the highway and there are no ridges between yourself and the peak to the southwest. Your position is on
the highest ridge that both lines cross.
The principal of triangulation is to shoot 2 or more points; where those points intersect is where you are. In this case the two lines coincided, but a third line was the ridge you were on. Thus, you had an intersection after all.
NOTICE: You did not once need to read a number off the compass. I called the bearings out in the above exercise for clarity. Pointing at each target you turned the bezel ring until the needle was “boxed”….and on the map you placed the compass with the base plate next to the target and rotated the entire compass until the index lines were parallel with the grid lines and then drew a pencil line.
2. To find your position using one known point and a linear feature:
In this example, you could shoot a bearing to the “get there” target and start walking overland but decide that is not your best option (…and it isn’t!).
You are on a road now and “get there” appears to be at the end of a road. You decide to use the roads.
Your decision is this; set 90° into your compass, continue walking up the road you’re on, keep that “hill” (red dot) in mind and keep it in view, when you can point your compass at the “hill” and the needle is “boxed” you will be on the road due west of the ”hill” (green dot), you now set 270° into your compass, walk about 1.5 km to the road that “get there” is on (purple dot), then turn left walk about 250 m and you’re there.
Thus, you will use a linear feature (the road you’re on) and a known point (“the hill”) to find the position on
the road where you want to turn (green dot).
NOTE: Any linear feature will work for this; such as a power line, wash, ridge, etc. But also the bearing line that you are traveling on can be used as a “linear feature”.
This video shows the sighting of a hill and that bearing plotted to a linear feature:
OFFSETTING YOUR BEARING and USING a HANDRAIL:
Let’s say you have stashed your bike at the “get here” dot. If in going from the “green dot” back to your bike, you were to measure the bearing and attempt to walk that bearing directly to the bike, chances are you will end up walking in circles looking for your bike.
So, instead you offset your bearing, in this case purposefully to the right, so that when you arrive at the linear feature, the road (purple dot); you know to turn left, walk 250 m and find your bike.
This is called ”using a handrail”. Blindfolded you could find the handrail and then the bike. Well, I don’t know about that….but kind of.
FINDING YOUR POSITION BY DETERMINING
THE COMPASS DIRECTION of the LINEAR FEATURE YOU ARE ON:
Use any feature, gullies, ridges, saddles, roads, especially roads, etc.
You are running down the canyon from WP 8; you’ve been running and running and are beginning to wonder where you’re at.
Standing in the bottom of the canyon you point your compass down the drainage/canyon.
Turn the bezel ring of the compass
until the needle is boxed.
NOTICE: You do not need to read a number; just….
Lay your compass on the map (forget the needle now) with the base plate along the blue line of the canyon bottom and move your compass around to different positions until the index lines of the compass are parallel with the grid lines of the map AND the base plate is along the blue line of the canyon bottom.