Let’s imagine this scenario.
You are hiking following a trail on your map, and unexpectedly you found a trail intersection in front of you that you don’t have on your map.
This can happen to you even if your map is just 2 years old.
So, which one of the trails is the one that you see on your map?
After you finish watching this lesson, you know how to answer this question.
Hello and welcome this lesson of the online course Wilderness Navigation Masters, where you will learn how to match your map to the terrain using bearings.
Saying that, means if I see a landmark in the real world I can pinpoint it on my map and vise versa.
Why should I match my map to the terrain using bearings:
You may ask me, but why should I match my map to the terrain using bearings, if I already know how to do it without bearings.
This is a good question.
You have to know how to do it using bearings because it’s more accurate.
Now that you see the importance of knowing how to match your map to the terrain using bearings, let’s start with how to take a bearing of a point landmark from your map and sight it on the terrain.
Take a bearing on your map and sight it on the terrain :
Taking a bearing from your map and sight it on the terrain is useful when we see a landmark on our map, but we don’t know in which direction he is in the real world.
To take a bearing from your map, you should have a north-south line to measure the angle between the geographic north and your point.
If you have a map like this, where the UTM grid north is the same as the geographic north, because the declination diagram doesn’t mention that there is an angle between the two,
you can use the UTM grid to get this north-south line.
If you don’t, I mean, there is an angle between the UTM grid north and the geographic north, you can draw a parallel line to the edge of your map.
[Skip the video below to 1:58]
Take a bearing on the terrain and sight it on the map
Taking a bearing on the terrain and sight it on your mao is helpful when you see a landmark in front of you but you want to know where is it on your map.
[Skip video to 4:23]
Till now, I still didn’t show you how to answer our first question of, if we are walking following a trail on your map, and suddenly you found a trail intersection in front of you that you don’t have on your map, how to know which one of them is the one on your map?
To answer this question, I should show you how to match your map to the terrain using bearings for linear landmarks.
- Step 1: try to pinpoint exactly where you are on your map.
- Step 2: Measure the angle between the geographic north and the general direction of this trail to get a bearing.
- Step 3: Shoot this bearing on the field, and now the direction of travel arrow point at one of your two trails in front of you, and this trail is the one on your map.
This technique of matching your map to the terrain using bearings can also help you to pinpoint exactly your location on your trail when you know that you may found two intermittent creeks on your way.
Because the bearing of this intermittent creek will be something below 90°, and the bearing for the other intermittent creek audience between 30° and 40°, when you arrive at an intermittent creek and you want to know which one of them you are at to locate yourself exactly on your map, take a bearing of the intermittent creek you found, and from the bearing, you can know if you are here or here.
Now let’s go to see the exercise of this lesson.
Besides the exercise, I want you to practice what you learned in this lesson because it’s the base for what we gonna see in the next ones.
If you didn’t understand something, do not forget that you can leave me a comment in the comments section below.
Thank you and see you in the next lesson.
Updated on December 6, 2021 by Ben