The
map is the essential tool of the sport and accordingly is
an orienteer's most vital piece of equipment.
Although it is possible to orienteer on almost any map, it is much
more enjoyable to use maps made specifically for orienteering. Such
maps are accurate and detailed, and are prepared on a human scale
This means that terrain and features are mapped so that what appears on
the map
are the features that a human, moving through the area, sees readily.
For example, boulders that are waist high would usually appear on
orienteering maps.
Most people are familiar with the Ordnance Survey maps, but
orienteering maps are special maps which differ from Ordnance
Survey maps as follows:
- Grid lines run
North-South only and indicate Magnetic North.
These lines (known as north lines) are parallel lines drawn
running from magnetic
south to magnetic north and spaced between 200 to 500 meters
apart on the map.
On the example shown here, they are drawn in black. The reason
that
the north lines on orienteering maps are not drawn pointing to
true
north is because orienteers often use compasses to orient the map
(to
magnetic north, not true north) as the angle between
magnetic
north and true north (the declination) varies widely in different
parts
of the world. It has thus become a standard to provide a series
of
reference lines on the map so that it is easy to use an
orienteering
compass to take a bearing.
- They are at a much larger scale and therefore allow much
more detail to be shown. In fact, anything permanent on the
ground which might act as a control site or aid navigation
is normally mapped. For example, natural ground features
(pits, knolls, crags etc.), vegetation features (thickets,
clearings etc.), and man-made features (fences, walls,
drains, buildings etc.) would usually be mapped.
Usually the scale of orienteering maps is 1:10,000 or
1:15,000 - this means that a distance of 1cm on the map
represents 100m or 150m on the physical terrain.
- The colours, signs and symbols are unique to orienteering
maps.
Usually a key or legend appears on each map, but after a few
events the colour and symbol definitions become second nature.
The colours on orienteering maps are used to depict vegetation
according to its density or runability. Yellow areas are
treeless, white areas indicate wooded area where you can
run, and dark green signifies very thick vegetation, often
impenetrable.
- Contours are much more detailed, usually appearing at
vertical intervals of 5m.
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