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Map Reading &
Navigation
Being able to navigate
from one place to another can mean the difference between life and
death.
This page can only hope to touch on
navigation in a small way. I'll use this page to generally describe what is
meant by 'Map Reading'.
First - let us ask ourselves what a
map actually is.
What is a map?
Wow! that's a coincidence, I was just thinking about that myself. I'm glad you
asked!
A map (in whatever form it might take)
is generally a pictorial representation of something larger and it enables users
of the map to 'navigate' their way around it.
Maps used for map reading in the countryside are generally topographic. Road
maps are normally used for navigating while driving and are usually of quite a
large scale. They are not much use for accurate map reading in, for example, the
mountains. For that you need something that shows the hills.
So, how do you get a three dimensional representation of the ground onto a two
dimensional piece of paper (the map) and still retain the topographic
information?
Well, first let's look at how it was
done in the olden days. When someone made a map, they generally got the ground
features such as towns, villages, churches about in the right place. But when
they came to hills or mountains, there was no way they could indicate this on
their map. So, they did a little drawing of a hill and wrote 'Hill' beside it.
For the really dangerous hills and mountains, they drew a larger hill (sometimes
with a jagged or pointy bit at the top) and wrote 'Beyond here be Dragons'. That
was the best to be hoped from maps for hundreds of years - until Dave came
along!
Dave worked for
Ordnance Survey and was tasked with the
job of trying to represent the third dimension. He played with the idea of using
colours to represent different height, and for some large scale maps this was
acceptable. But for maps with a scale of 1:50,000 (2cm=1km) or 1:25,000
(4cm=1km), he needed something much more accurate.
Dave came home one night dejected
because he couldn't think of anything - until he saw his dear wife who had just
returned from Weightwatchers.
She was lying on the floor in front of
the fireplace doing her exercises in just her bra and panties. She was wearing a
circle stitched bra, and being a rather large (but still beautiful) woman
reminded Dave of a couple of large hills. The circle stitching on the cups of
her bra gave Dave the idea that height could be represented by drawing lines
around objects at the same height and marking the lines on a two dimensional map
would therefore give the third dimension.
The next morning, Dave bought all the
string he could lay his hands on and proceeded to lay it all around the nearest
hill at exactly ten metres in height. He then laid some more at twenty metres in
height and so on till he reached the top of the hill.
He then rented a hot air balloon for a
day and, floating above the hill with his two dimensional map, drew the lines
made by the string on the ground. And so, CONTOUR LINES were invented. You can
see them on every topographic walking or hiking map to this day.
It is this information coupled with
your ability to interpret it that could save your life.
The example here shows the contour
lines as they would appear if drawn onto the hills (like Dave did with the
string).
This site is owned by Bushcraft Educational Society © 2005
Email:
info@bushcraft-educational-society.co.uk
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