importance of being able to read a map and compass proficiently can
not be highlighted enough. I mean lets face it, you don't want to be
one of those people who have to be rescued by the Mountain Rescue team
because they got lost when a little mist came down. Or on a more sombre
note, you don't want to be one of those people who are less fortunate
and are not rescued in time.
long and short of it is that the mountains in Scotland can kill, so
we shouldn't underestimate them or take them lightly. All it takes is
a short time to learn those basics and enhance your safety on the mountains.....
so how much do you know?
The grid lines on Ordnance Survey maps are used to:
1. Determine the grid reference of a location
2. Find a location from to its grid reference.
and Using Grid References
Grid references are 6 digits long. The numbers are two batches of three,
where the first two digits of the batch indicate the "box"
the landmark falls in. The third digit indicates the location of it
within the box. For example, the 0 in 670 would be exactly on the grid
line 67 and where 675 would be half way from grid line 67 to grid line
Ordnance Survey maps are 1km apart regardless of the scale of the map.
- the figures are read vertically bottom to top up the map and the lines
that join these figures run horizontally left to right
Eastings - the figures are read horizontally left to right across
the map and the lines that join these figures run vertically top to
Grid refs. should be read from the map in the following order:
Eastings (i.e. across the map east to west)
(i.e. down the map north to south
Eastings; Northings = E then N (alphabetical order)
basic Silva Compass will provide you will all the functions you
are likely to need.
Try and guess the bearing you are about to calculate.
Remember the Cardinal Points/4 Quadrants of
your compass - North 0 degrees; East 90 degrees; South 180 degrees;
West 270 degrees and North 360 degrees This gives you a cross
Alarm bells should begin to ring when your guess
is way out (usually about 180 degrees!) from the bearing you
have worked out.
out map and compass on top
Set Orienting Arrow (big, black/red depending on your compass type
which lines up with North/0 degrees on your compass dial) to North
(top) of map.
Line up accurately with grid lines by turning dial.(Use orienting/parallel
Place edge of compass along line A - B.(You are
walking from A to B - Direction of Travel Arrow points this way)
[Mistake No 1 - You have the compass back to front i.e.
Going from B to A]
[Mistake No 2 - lining up the orienting lines with North
on your dial pointing to the left right or bottom of your map;
MUST be to top]
Read grid bearing against your direction of travel arrow/ line,
turn dial anti-clockwise to add 5o
(five degrees - 1 mark = 2 degrees) to give magnetic bearing.
Lay aside map; swing compass in hand until red magnetic needle and
black/red orienting arrow are together.
Walk in direction of arrow at front of compass. (Direction of Travel
out map and compass on top
the bearing on the compass to north
the edge of the compass base plate and the orienting lines on
the compass with the eastings (gridlines running east to west)
the map (and yourself) until the red end of the arrow points north.
are now facing north and the top of the map is now pointing north.
a feature on the ground to get a bearing
the compass's "direction of travel" arrow at a feature
on the ground (i.e. a house in the distance). Turn the housing until
the red "N" lines up with the rotating arrow.
can travel along this bearing using the compass or you can convert
it to a map bearing to plot a location by:
Subtract 5o (as it is Mag to Grid - GET
RID - see below for more information)
the compass on the map until the orienting lines are parallel
to the map eastings and the base plate is running through your
current position on the map.
objects can cause the needle to deviate from north. Stand clear
of metal objects.
hold the compass flat - it allows the needle to move round freely
care of your compass - a damaged compass could become inaccurate
use an up to date map as old maps may be missing information or
may even detail landmarks that are no longer there.
your compass if it develops a large air bubble. Work on the safe
tell someone your route for the day - even if it is a simple route.
The make sure you stick to the route you planned!
sure you are properly equiped and fit and capable enough to complete
your chosen route with ease.
A list of mountain safety recommendations:
DO wear good walking boots and wear or carry waterproof
jacket and trousers
DO carry a map and compass and know how to use them
DO carry a whistle and know the international distress
DO prepare a route card and leave a note of your
DO carry enough food and drink for more than a full
day on the hills
DO carry a survival bag and spare clothing
DO carry and ice axe, crampons and torch in winter
and be proficient in their use
DONT go to the hills alone if you are inexperienced
DONT overestimate your own abilities
DONT underestimate the variability of Scottish
Mountain Weather at any time of the year
True, Grid and Magnetic North
and south are located at the geographic poles.
North is the direction to which all of the Ordanance Survey maps
are orientated. All the map bearings that are taken use grid north.
North is the direction that a compass points to. In the UK this
is approximately 5o west of grid north.
difference between grid and magnetic north is referred to as the magnetic
variation and must be taken into account when translating bearings
from or onto maps.
how do you deal with magnetic variation?
the information we take from a map is based on grid bearings and the
information from a compass is based on magnetic bearings, when we
move from one format to the other we must take this into account.
This is simply by either the subtraction
or addition of the magnetic variation (5o) to
convert the bearing.
to mag(netic) - ADD (i.e. add to the grid bearing)
to grid - GET RID (i.e. subtract from the magnetic bearing)