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Contours. Part 2. Visualisation.
Visualising the shape of the land is a very useful
skill for orienteers. It enables you to predict what you will see on
your chosen route. Once you have mastered it you find that navigation
is no longer a puzzle that is frequently on the verge of becoming
incomprehensible. Rather you become confident that the shape of the
land will help you find your way even when line features are few and
far between. It can also help you identify much more quickly when you
have deviated from your chosen route. So how skilled are you in this
area? If you were to pick up an unfamiliar map now would you be able
to predict how the land would appear? Armchair orienteering may not
sound very exciting but taking the time to sit down and look at
orienteering maps away from the race situation can be a very valuable
exercise. Without pre race nerves, oxygen debt or the pressure of
other orienteers around, you are free to take your time and work out
exactly what information is set out on the paper. In the last article
on Orienteering techniques the basics about identifying high and low
land and steepness of gradient were discussed. This is a starting
point but only touches the surface of how contour lines can help the
orienteer. To be able to produce consistently good results you need to
develop this basic interpretation much further.
Focussing on an individual orienteering technique is good for
improving it but at some point you need to start using the techniques
together. Here visualisation is combined with "traffic light
orienteering" i.e. dividing the leg into 3 parts, green, orange and
red. You will recall that the green section accounts for the longest
part of the leg. You need to keep navigation simple so as to move
swiftly through the terrain. Your visualisation also needs to be
simple - look at the general shape of the land. Is there a hill or
large knoll? What is your general movement direction in relation to
the contours? If contouring, work out if the high land is on your left
or right. If you are crossing the contours will you be going up or
down hill? Perhaps there is a re-entrant, ridge or a distinctive line
of knolls that will keep you heading in the right direction. Avoid
looking at small features such as dot knolls, pits or any feature
which will be difficult to find; small features and 'green'
visualisation are incompatible.
The orange phase is when you are approaching your attack point - this
should be a distinctive feature that is reasonably close to the
control. Navigation has to be more precise so you may find yourself
using smaller features to assist - the detail in your visualisation
has to match this so you might be thinking of shapes of hills, larger
knolls, re-entrants. Whenever possible avoid getting embroiled in the
smallest details at this stage.
You enter the red section after your attack point. Now is the time to
use smaller features if there are no larger ones to use and again
your visualisation should be on the same scale. Visualising small
"negative" features e.g. pits and small depressions is rather
difficult and should generally be avoided - they are notoriously hard
to find. Much better to use features such as knolls (their height and
shape), small marshes, clearings, crags and boulders. As long as you
are not in the middle of "fight" or thick bracken you will find this
type of feature reasonably quickly.
Below are some examples. Look at the map extracts and try to work out
what you will see before looking at the written descriptions. Think
about the land forms you will see, traffic light orienteering,
distance judgement and other orienteering skills that you use.
@ Crown Copyright. All rights reserved. PU 43423U. BOF Map
Registration No. 0172SO.
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The initial impression is of a mass of brown
lines and no line features, but don't panic. First of all work out
where the highest land is - in this case it is to the south of the
leg. Next look at the shape of the contours which the direct line
crosses. You can see there are two spurs. These will help you keep
track of where you are in the terrain. You could try contouring but in
my experience this is very difficult. In theory there should be
advantages but in practice it is all too easy to lose height without
realising. So I would advise taking a bearing. Take note of the
distances between features. After 130m you should have found your
first spur. After another 200m you will have found the second spur,
which has a large crag on it. You are now in the red phase of the leg.
The spur is your attack point. With luck you will be within sight of
the crag, skirt round below it until you reach the other side of the
spur and you are in the shallow re-entrant. The flag should be visible
now.
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@ Crown Copyright. All rights reserved. PU 43423U. BOF Map
Registration No. SO-01-368
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Again take a moment to identify high and low land. In this case
not too difficult - no 7 is on a re-entrant which is on the side of
a small hill. Leave the control heading in a north easterly
direction and skirt around the end of the small hill. On your left
there should be a knoll. Pass between these two features and then
drop down to follow the long spur which heads towards the next
control for a distance of about 200m. (However beware: if you fail to
identify the knoll on the left you run the risk of following the
shorter spur to the south. ) You will notice that re-entrants run
along both sides of the spur that you are to follow so the land form
is well defined, and provided you pay attention, you should not stray.
You are now in the orange phase of the leg. When you reach the end
of the spur you are about 100m from the control. To reduce the
possibility of error follow a bearing in the direction of the control
site. En route you will expect to cross a linear marsh just before
skirting around the side of a large knoll. You are now in the red
phase of the leg. A smaller knoll should be in sight now and the
control flag should be visible.
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@ Crown Copyright. All rights reserved. PU 43423U. BOF Map
Registration No. SO-01-360
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The forest around 14 is relatively featureless and it is all too
easy to head off in the wrong direction so take a rough bearing.
Follow this bearing for 110m. On reaching the forest road you will be
climbing up hill. By aiming to pass between the two knolls at the
top of this rise you will be able to predict with confidence where you
should begin your descent. Cross the road. You are now entering the
orange phase. To your left there should be a spur, ahead of you the
ground slopes steeply down. Head straight down for about 100m until
you find the clearing. This is now the red section of the leg. You
should now find the thicket with little difficulty.
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How did your description of route choice compare with those given
above? I am sure that there would be differences. Alternative route
choices are inevitable in orienteering but what matters is your
ability to visualise what you will see and in knowing your own
strengths and weaknesses both physically and in navigation skills. As
with all things the more you practise the better you will get so why
don't you take the time to look at some of your own maps - preferably
use areas that you are less familiar with? You don't have to confine
this activity to indoors. You could also take an orienteering map out
with you next time you go for a training run. (The map doesn't have to
be of the area you are running in.) This will give you the
opportunity to practice reading the map while moving. Another good
time to practise is at the club's Saturday morning events. This way you
get confirmation of whether you are successfully interpreting the map
but you do need to be able to resist the temptation to race your
rivals for the best result!
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