TROOP 23 ONLINE....... Using A Compass |
Kjetil Kjernsmo's illustrated guide on
This is the important lesson, and you should learn it well.
It's when you use both compass and map the compass is really good, and you will be able to
navigate safely and accurately in terrain you've never been before without following
trails. But it'll take some training and experience, though.
I am not covering map reading here, guess you would have to consult other sources for that, but the lesson will be useful if you have a sense of what a map says.
First, a quick summary of what you will learn in this lesson:
Here is our compass again: 
The principles are much the same as in lesson 1 but this time, you are using the map to tell you which way is correct instead of your intuition.
Take a map. In our first example, we look at a map made for orienteering,
and it is very detailed. Well, not really. We look at a fictitious map I drew myself, but
never mind. To the point.
You
want to go from the trail-crossing at A, to the rock at B.
Of course, to use this method successfully, you'll have to know you really are at
A.
What you do, is that you put your compass on the map so that the edge of the compass is at
A. The edge you must be using, is the edge that is parallel to the direction of travel
arrow. And then, put B somewhere along the same edge, like it is on the drawing. Of
course, you could use the direction arrow itself, or one of the parallel lines, but
usually, it's more convenient to use the edge. At this point, some instructors say that
you should use a pencil and draw a line along your course. I would recommend against it.
First, it takes a lot of time, but offers no enhancement in accuracy of the method.
Second, if you have wet weather, it may destroy your map, or if it is windy, you may loose
it. You should keep your map (preferably in a sealed) transparent plastic bag, and if it
is windy, tied up, so it can't blow away. But most important is that any drawings may hide
important details on the map.
Time to be
careful again! The edge of the compass, or rather the direction arrow, must point
from A to B! And again, if you do t
his wrong, you'll walk off in the exact opposite direction of what you want. So
take a second look. Beginners often make this mistake as well.
Keep
the compass steady on the map. What you are going to do next is that you are going to
align the orienting lines and the orienting arrow with the meridian lines of the map. The
lines on the map going north, that is. While you have the edge of the compass carefully
aligned from A to B, turn the compass housing so that the orienting lines in the compass
housing are aligned with the meridian lines on the map. During this process, you don't
mind what happens to the compass needle.
There are a
number of serious mistakes that can be made here. Let's take the problem with going in the
opposite direction first. Be absolutely certain that you know where north
is on the map, and be sure that the orienting arrow is pointing towards the north on the
map. Normally, north will be up on the map. The possible mistake is to let the
orienting arrow point towards the south on the map.
And then, keep an eye on the the edge of the compass. If the edge isn't going along the
line from A to B when you have finished turning the compass housing, you will have an
error in your direction, and it can take you off your course.
When you are sure you have the compass housing right, you may take the
compass away from the map. And now, you can in fact read the azimuth off the housing, from
where the housing meets the direction arrow.
Be sure that the housing doesn't turn, before you reach your target B!
The final step is similar to what you did in lesson
1.
Hold the compass in
your hand. And now you'll have to hold it quite flat, so that the compass needle can turn.
Then turn yourself, your hand, the entire compass, just make sure the compass housing
doesn't turn, and turn it until the compass needle is aligned with the lines inside the
compass housing.
The mistake is
again to let the compass needle point towards the south. The red part of the compass
needle must point at north in the compass housing, or you'll go in the opposite
direction.
It's time to walk off. But to do that with optimal accuracy, you'll have to
do that in a special way as well.
Hold the compass in your hand, with the needle well aligned with the orienting arrow.
Then aim, as careful as you can, in
the direction the direction of travel-arrow is pointing. Fix your eye on some special
feature in the terrain as far as you can see in the direction. Then go there. Be sure as
you go that the compass housing doesn't turn.
If you're in a dense forest, you might need to aim several times. Hopefully, you will
reach your target B when you do this.
At this time, you may want to go out and do some training, so you could check out some suggested exercises.
Unfortunately, sometimes, for some quite often, it is even more complicated. There is something called magnetic declination. And then, for hiking, you wouldn't use orienteering maps. And this is the issue for lesson 3.
BSA TROOP 23 |
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