game-library/data/sources/orienteering-compass-skills.txt

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Scout Skills
Compass
0845 300 1818
housing has etched orienting lines and an
INFORMATION SHEET
orienting arrow, whilst the baseplate (on which
the housing is mounted) has the direction of
A compass is an instrument with a magnetised travel arrow and map scales etched onto it. This
needle which points to (magnetic) north and is compass allows for bearings, an accurate
therefore used for determining direction. They method of determining direction, to be worked
come in different shapes and sizes and indeed, out and is therefore the compass of choice for
the use of suspended magnetic ore (which hiking and expedition type activities.
always comes to rest in a north-south direction)
was used many centuries ago as a primitive form
of compass. Today, in one form or another,
compasses are used on land, at sea or in the air,
to help people to specify direction.
Types of compass
Air damped compass - This is the simplest and
Why use a compass?
cheapest form of compass and does little more
than indicate the approximate direction of
magnetic north. It takes a long time to stabilise As you can see, it is possible to have a varying
and the slightest movement makes the needle quality of compass depending upon what job it
move. This compass should never be used for has to do and of course, ultimately, how much
any sort of hike or expedition. you pay for it!
Simple map setting compass - It is a liquid filled Apart from determining the direction of north, a
compass with only magnetic north marked on it compass enables you to work out a compass
and can be clipped onto the side of a map. It is bearing. This is the angle measured in the
useful for positioning a map until whatever is in number of degrees between 0 and 360 which
front of you in reality, is in front of you on the tells you the direction from one place to another.
map. This can only be approximate as there is We call the direction north '0' and therefore, it
no allowance for magnetic variation, that is, the follows that east is 90 degrees, south-west is 225
difference between magnetic north and grid degrees and so on.
(map) north. (This is explained in more detail
later on). If we just used the points of the compass, (north,
south, east, west and so on) we would only get
Prismatic compass - This is a more expensive
type of compass with a prism which enables a
compass bearing to be taken while sighting your
objective. It can be more accurate than other
compasses but it is harder to use and therefore
should only be used once the basic principles of
map and compass work have been mastered.
Silva type compass - This consists of a
magnetised needle suspended in an alcohol filled
housing. The liquid helps to 'dampen' movement
of the needle enabling it to be read more quickly
than air damped compasses. The compass
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The Scout Association, Information Centre, Gilwell Park, Bury Road, Chingford, London E4 7QW. Email: info.centre@scout.org.uk
Website www.scoutbase.org.uk Direct: 020 8498 5400 Local rate call: 0845 300 1818 Fax: 020 8498 5407

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eight different directions (or possibly 16 or 32 at Ocean, west of Cornwall. The majority of grid
most if we further divided the compass points, lines are 1.5 degrees west of true north and are
for example, south-southwest or north by therefore useful lines to refer to when taking
northeast and so on). By using bearings, we can bearings.
have 360, which enables us to be much more Magnetic north - A compass needle points to the
accurate. magnetic north pole. Unfortunately, it is not in
the same position as the true North pole. The
Once we have determined a direction (and magnetic north pole is currently located in the
bearing) in which to travel, it can then be Baffin Island region of Canada, and from the
checked at regular intervals to confirm that we United Kingdom, it is west of true north. The
are still going in the correct direction whether or difference between grid north and magnetic north
not our destination can be seen. is known as the magnetic variation and its value
can be found in the orientation panel or margin
of an Ordnance Survey map.
When using a compass proficiently, it is
necessary to be able to:
• Take a bearing - determine the angle As true north is only about 1.5 degrees off grid
north, it is so small that it is normally disregarded
between north and the direction of an object
and only grid north and magnetic north are used.
in terms of degrees;
• Walk on a bearing - use a bearing to get to a
destination without necessarily using a map; Magnetic variation
• Set a map - use a compass to correctly
position a map in order to represent what can The magnetic variation, (the difference between
actually be seen. magnetic north and true north), is caused by the
North and South poles not being directly
(Details on how to do these are covered in the
'opposite' one another. The lines of the Earth's
Teach Yourself section.)
magnetic field do not run in a regular pattern as
they are affected by other local magnetic forces
The three norths
and the magnetic pole is always on the move.
Some of these lines of magnetic variation are
When working with a map and compass, there east of true north and others west of true north.
are three different 'norths' to be considered! Between the east and west lines there is a line of
Fortunately, in the United Kingdom, for practical zero magnetic variation where the compass does
purposes, we only have to consider and work point to true north - this line is known as the
with two of them. agonic line currently running through eastern
True north - Each day the Earth rotates about its Canada, United States of America and South
axis once. The ends of the axis are the true America.
North and true South poles.
Grid north - The grid lines, pointing to grid north, However, not only does the magnetic variation
on Ordnance Survey maps divide Great Britain change as you move across the Earth's surface,
into 100 kilometre sections. They are then it also changes with time. In the United
further sub-divided into one kilometre squares, Kingdom, the magnetic variation in 1991 was
east of an imaginary zero point in the Atlantic about 6 degrees and decreasing at an
approximate rate of 0.5 degrees every three
years.
It is important to check the magnetic variation
regularly, and this can be found on a map's
orientation panel or margin. Remember also to
check the year the map was printed, as a map
that is 20 years or so old, could be up to 3 or 4
degrees out! In fact, the magnetic variation also
varies from side to side and top to bottom on
each and every map but these details can also
be found on the map.
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The Scout Association, Information Centre, Gilwell Park, Bury Road, Chingford, London E4 7QW. Email: info.centre@scout.org.uk
Website www.scoutbase.org.uk Direct: 020 8498 5400 Local rate call: 0845 300 1818 Fax: 020 8498 5407

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This magnetic variation is important when
combining a map and compass as you need to
convert bearings from 'map to field'. To convert
grid bearings (which are indicated by a map) to
magnetic bearings (as per the compass pointing
to magnetic north), add the current variation by
turning the compass housing anti-clockwise. For
example, if the current variation was 6 degrees,
a grid bearing of 122 degrees would become 128
degrees. This is what the dial should be set at.
The reverse is true for converting a magnetic
bearing to a grid bearing; that is, subtract the
current variation.
For expeditions abroad however, some parts of
the world will not only have a different value, but
may also be east of true north, in which case,
when converting from grid to magnetic bearings,
the magnetic variation should be subtracted from
the compass bearing.
Further information and resources
Ask other Leaders experienced in the use of the
map and compass for advice and ideas. Do they
know of opportunities for practising or learning
how to use them?
There are also plenty of books available on this
subject, both at a beginner's level, and more
advanced.
Camping and Outdoor centres and other high
street shops selling camping and hiking
equipment may be able to offer advice.
3/9 Scout Skills Compass(cid:211) The Scout Association 2000 – Item code: FS315074 (Format Revision Aug 2000)
The Scout Association, Information Centre, Gilwell Park, Bury Road, Chingford, London E4 7QW. Email: info.centre@scout.org.uk
Website www.scoutbase.org.uk Direct: 020 8498 5400 Local rate call: 0845 300 1818 Fax: 020 8498 5407

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TEACH YOURSELF Walking on a bearing
This is used when you can initially see your
objective or destination and don't need a map. It
Understanding how to use a compass is like
is important to work out a compass bearing
many other activities; it's easy when you know
before the situation changes. This might be due
how! Practice is also the only way to get it right
to the weather (rain, fog and so on), the terrain
and remember it. Although this sheet can help
you are in (valley, hills and so on) or a delay
you through the different stages, the only
resulting in darkness. Any of these factors may
effective way to learn is to go out and use the
mean you can no longer see where you are
compass for real. Ask experienced Leaders for
aiming for and, therefore, you will need to rely on
advice and also take part in a hike or expedition
the compass bearing.
to put the skills into practice.
1. Turn the housing of the compass until the
Time
bearing you require is against the index
pointer.
Up to one hour may be required to become 2. Turn the compass until the needle lies over
familiar with the parts of a compass and the the orienting arrow.
principles of how to use it, especially in
3. Pick out a landmark along your direction of
conjunction with a map, but more time will be
travel line and walk towards it.
required in shorter sessions to put it into practice.
4. Check your bearing and your objective at
regular intervals.
Equipment
Setting a map with a compass
A Silva (type) compass and an Ordnance Survey
map of the area you are in.
This is for when you are using a map in
conjunction with a compass to reach a given
Learning all about it destination, probably in unfamiliar territory.
Before having a go, you will need to read the 1. Turn the compass housing until the magnetic
Information Sheet if you have not already done variation for the area is shown against the
so. index pointer.
2. Place the direction of travel arrow pointing
Taking a bearing along the vertical grid line with the direction
of travel arrow pointing to the top of the map.
3. Turn the map with the compass in this
1. Hold the compass flat in your hand with the
position until the compass needle points to
direction of travel arrow pointing towards
the north mark on the compass housing.
your destination or objective.
3. Your map is now 'set' and you should be able
2. Turn the compass housing until the compass
to recognise actual features from your map
needle lines up over the orienting arrow.
in front of you.
Ensure the north pole of the. needle, usually
red, is used.
3. Read off the magnetic bearing (that is, the Combining map and compass
number of degrees) from the mark on the
compass housing indicated by the index 1. Place the compass on the map so that one
pointer. long edge joins the start point and your des-
4. Keep the housing in that position and check tination, with the direction of travel arrow
your bearing at regular intervals by lining up pointing towards the direction you wish to
the needle with the orienting arrow and travel. (The direction of the map does not
walking in the direction indicated by the matter for this exercise).
direction of travel arrow. 2. Turn the compass housing until the orienting
arrow points to the top of the map and the
orienting lines are parallel to the grid lines.
4/9 Scout Skills Compass(cid:211) The Scout Association 2000 – Item code: FS315074 (Format Revision Aug 2000)
The Scout Association, Information Centre, Gilwell Park, Bury Road, Chingford, London E4 7QW. Email: info.centre@scout.org.uk
Website www.scoutbase.org.uk Direct: 020 8498 5400 Local rate call: 0845 300 1818 Fax: 020 8498 5407

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3. Take the compass off the map and read off • Orienting arrow pointing to the bottom of the
the bearing at the index pointer and add (or map. Again, you will walk (180 degrees out)
subtract) the local magnetic variation. in the opposite direction.
4. Turn the whole compass so that the needle • Not taking account of the magnetic effects of
comes to rest over the orienting arrow, with iron and steel around you. For example,
the red part to the north. watches, steel buckles, cars, buried pipes,
5. Hold the compass in front of you, pick out a reinforced concrete, wire fences, railway
landmark along your line of travel and walk lines and other compasses (and even
towards it. magnetic rocks!) can influence your
compass. That is, these items might attract
the compass needle in preference to the
magnetic north pole therefore giving you an
inaccurate reading. If in doubt, try to move
away from such objects.
Avoiding obstacles
Sometimes when using a map and compass you
will come across obstacles such as a lake, wood
and so on that cannot be crossed and you must
get round them somehow. The problem is to
avoid the obstacle without losing direction.
Common errors
The obstacle may be by-passed by going round it
When first learning how to use a compass, there
by a series of right angles; walk at 90 degrees to
seem to be many things to take into
your original route, count the number of paces
consideration - here are a few things which often
until you clear the object. Turn 90 degrees again,
'go wrong':
so that you are not parallel with your original
• Failing to add on the magnetic variation. If bearing and walk past the obstacle. Turn 90
the magnetic variation is, for example, 6 degrees again and walk the same number of
degrees, and you forget to add it on, you will paces, then, finally, turn through 90 degrees to
be 105 metres off course for every kilometre bring you back on your original course.
travelled in a straight line. This gets
proportionally bigger over greater distances.
This may seem rather pedantic, but it does work
providing the number of paces and turns are
accurate. This can be vital if the weather takes a
turn for the worse. An error of just 2 degrees
over a journey of say, just six kilometres means
that you will miss your target by 200 metres
which if you find yourself fog-bound, and it's the
only habitation for 20 miles around, might be
fatal!
Can you do it?
When you feel confident about using a compass,
check how you are doing and see which of the
following you can tick off:
Name the parts of a Silva compass (cid:149)
Take a compass bearing (cid:149)
• Not having the direction of travel arrow Set a map using a compass (cid:149)
pointing from your start to finish. If you Walk on a compass bearing (cid:149)
make this mistake you will walk 180 degrees
Walk around obstacles maintaining the correct
out from your intended route.
direction (cid:149)
5/9 Scout Skills Compass(cid:211) The Scout Association 2000 – Item code: FS315074 (Format Revision Aug 2000)
The Scout Association, Information Centre, Gilwell Park, Bury Road, Chingford, London E4 7QW. Email: info.centre@scout.org.uk
Website www.scoutbase.org.uk Direct: 020 8498 5400 Local rate call: 0845 300 1818 Fax: 020 8498 5407

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Explain the importance of magnetic variation (cid:149)
Explain the difference between true north,
magnetic north and grid north (cid:149)
So you want more?
Have a go at orienteering - this is using a map
and compass over a given area in the form of a
competition.
Learn how to take and use back bearings.
Learn how to draw a resection of map which
would enable you to locate your position.
Your notes on this session
6/9 Scout Skills Compass(cid:211) The Scout Association 2000 – Item code: FS315074 (Format Revision Aug 2000)
The Scout Association, Information Centre, Gilwell Park, Bury Road, Chingford, London E4 7QW. Email: info.centre@scout.org.uk
Website www.scoutbase.org.uk Direct: 020 8498 5400 Local rate call: 0845 300 1818 Fax: 020 8498 5407

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HOW TO TRAIN OTHERS the aspects that should be covered can be found
in the Information Sheet and Teach Yourself
sections.)
This section is designed to give some practical Here is a typical session outline that you may
ideas about how you can help other people to wish to follow or adapt:
understand how to use a compass. This might be • Start with making a simple compass (see
Leaders or Scouts - either in an informal way on
overleaf), and outline the purpose of a
a Troop night or more formally on a skills
compass.
workshop, training course or something similar.
• Follow this by explaining the difference
between magnetic, true and grid north, and
Objectives
the importance of magnetic variation.
• For Scouts it might be advisable to play a
I. By the end of the session, participants game or activity which checks their
will be able to: knowledge and understanding of the
II. Describe the different parts of a Silva compass points.
type compass; • Outline the different parts of a Silva type
III. Explain the difference between true compass; this can be either done by showing
north, magnetic north and grid north; a visual aid or a large example of a compass
IV. Demonstrate how to take a compass or better still, having a go at constructing a
bearing; paper version, as in the attached example.
V. Demonstrate how to set a map using a • If possible, go outdoors at this stage, and
compass bearing; using a map and compass, explain to, and
VI. Demonstrate how to walk on a compass encourage the participants to have a go at,
bearing. setting a map, taking a bearing, walking on a
bearing and combining a map and compass.
It might be helpful if participants are in pairs
Time
for this activity so that they can help each
other. Large groups might mean that not
Allow up to one or two hours to explain the everyone has a go or learns effectively.
principles of how to use a compass and to have • Once the participants are happy with the
an initial go at putting it in to practice. Follow up
principles of how to use a compass, have a
sessions at a later date will be important to
go at some of the activities outlined below
reinforce the learning.
either individually or as a series of bases.
You could also arrange a short hike, perhaps
Equipment in unfamiliar territory, to reinforce what they
have learned. It will also be helpful to follow
up with some of these activities at a later
Silva type compasses, various Ordnance Survey
date.
maps including one or more of the local area.
MAKE YOUR OWN COMPASS – METHOD 1
Visual aid of a Silva type compass and its
component parts. (The attached compass outline
could be used as an overhead projector Equipment
transparency - see final page.)
Sewing needle Sheet of thin paper
Equipment as per the training activities chosen. Pencil Sheet of A5 paper
Permanent magnet 15cm of cotton
Training methods Empty jam jar Felt-tipped pen
There is no substitute for letting participants get What to do
'hands-on' experience but there will need to be
some introduction and explanation. This and the
• The needle is held down with one finger and
activities and games will obviously need to be
stroked with one pole of a permanent
adapted according to whether it is adults or
magnet. It is important that the needle is
Scouts who are the participants. (Details on all
7/9 Scout Skills Compass(cid:211) The Scout Association 2000 – Item code: FS315074 (Format Revision Aug 2000)
The Scout Association, Information Centre, Gilwell Park, Bury Road, Chingford, London E4 7QW. Email: info.centre@scout.org.uk
Website www.scoutbase.org.uk Direct: 020 8498 5400 Local rate call: 0845 300 1818 Fax: 020 8498 5407

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always stroked in the same direction. The lies in the same direction as the pointed end
more times the needle is stroked the more of the magnetised needle.
molecules are pulled into line and the
stronger the magnet will become.
TRAINING ACTIVITIES
• Cut a two centimetre square of thin paper
and push the magnetised needle through it.
Compass Change
• Make a small hole in the top of the paper
and carefully tie a length of cotton through
Equipment
the hole.
• Tie the paper and needle to the pencil and
rest it across the top of the jam jar. The jam None required.
jar prevents the wind and air currents moving
the needle. In small groups, the participants form a circle
• Mark the AS sheet of paper in felt-tipped pen facing inwards. Each participant represents a
with the points of the compass (N/E/S/W). main compass point (N, NE, E, SE, and so on),
except one person who is 'it'. This person stands
in the centre of the circle. 'It' calls out two
compass points. The participants representing
these points then attempt to change places and
'it' tries to take the place of one of them. The
participant then left without a place in the circle,
becomes the next 'it'.
Sheet of thin paper Sheet of AS paper 15cm of
cotton Felt-tipped pen COMPASS POINT
Equipment
None required.
Gently lift the jar and rest it until the north lies in
the same direction as the pointed end of the
The participants stand together in the middle of
magnetised needle. You now have a compass!
the room all facing the same direction
MAKE YOUR OWN COMPASS – METHOD
How to Use
TWO
• Photocopy this page
Equipment
• Cut out the three parts
• Pinch or cut holes in the centre marked ‘+’.
Needle - magnetised as in Method 1.
• Fasten the parts together using a brass
Piece of cork or polystyrene.
paper fastener or press stud.
Saucer of water.
Piece of A5 paper.
Felt-tipped pen.
What to do
• Rest the magnetised needle on a small piece
of floating cork or polystyrene in a saucer of
water. The magnetised needle will turn the
cork or polystyrene into 'an approximately
north-south direction.
• Mark the A5 sheet of paper (using the felt-
tipped pen) with the points of the compass.
• Gently lift the saucer onto the middle of the
compass card. Turn the card until the north
8/9 Scout Skills Compass(cid:211) The Scout Association 2000 – Item code: FS315074 (Format Revision Aug 2000)
The Scout Association, Information Centre, Gilwell Park, Bury Road, Chingford, London E4 7QW. Email: info.centre@scout.org.uk
Website www.scoutbase.org.uk Direct: 020 8498 5400 Local rate call: 0845 300 1818 Fax: 020 8498 5407

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9/9 Scout Skills Compass(cid:211) The Scout Association 2000 – Item code: FS315074 (Format Revision Aug 2000)
The Scout Association, Information Centre, Gilwell Park, Bury Road, Chingford, London E4 7QW. Email: info.centre@scout.org.uk
Website www.scoutbase.org.uk Direct: 020 8498 5400 Local rate call: 0845 300 1818 Fax: 020 8498 5407