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Navigation
Basic to Advanced Navigation
What is navigation?
–noun
1. the act or process of navigating
2. the art or science of plotting, ascertaining, or directing the course of a journey
Essentially…
Navigation is about route finding. It can appear complicated but is actually very simple. Good navigators will ask themselves three questions….
1. Where am I? (Position fixing)
2. Where am I going to? (Direction finding)
3. How do I get there?
The navigators toolbox
There are various techniques and tools which can be utilised to aid navigation. A good navigator needs to know which tool to use in a particular situation
The navigators toolbox • A solid understanding of maps
• Scale, colour, contours, grid lines and conventional signs • Compasses, compass bearings and back bearings • Aiming off, handrails, attack points
MapsA map is a two dimensional representation of a
three dimensional geographic area
The process of map making
1) Aerial photographs are first taken of a given area by aircraft2) These images are then reproduced manually by cartographers
Maps
Colour
It is frequently necessary to get a fast overview of a given area and the colours used on maps give
an indication as to the type of terrain and relief of the land
Water
Vegetation
Areas of high altitude
Maps Shapes
All 3 dimensional features in our environment have some form or shape which can be
represented by a map. Different features have different shapes however there are some
generalisations we can make:• Man made features are generally
regular • Natural features are generally irregular
Scale
Scales and ratios
1:50,000 1:25,000
1cm on the map is equivalent to
50,000cm on the ground
1cm on the map is equivalent to
25,000cm on the ground
Scale continued….Different scales on maps are useful for different purposes
1:50,000 maps are useful for…. • Route planning
• Route overviews
1:25,000 maps are useful for….• Detailed information
• Wild country
Grid linesGrid lines are laid over all Ordnance Survey maps and are an aid to help locate features
Vertical grid lines are called….
Northings
Horizontal grid lines are called….
Eastings
Northings and Eastings enable us to do grid references (4 and 6
figure)
Problem…The terrain is three dimensional and maps are two dimensional
So how do cartographers represent relief (peaks and troughs in the land) on a 2 dimensional map?
Contour Lines, spaced at 10m intervalsThus, land can rise up to 9.5m above sea level
without being represented by a contour line!
Calculating timeA key feature of route planning is the ability to accurately
calculate the time required for any given journey
This is calculated by a simple formula:
Naismith’s Rule: “4km / hour or 1km / 15 minutes
+ 1 minute for every contour line”
Conventional signs
Conventional signs or map symbols perform the same function as icons on a computers desktop
They are a fast and effective way of depicting a particular feature, either manmade or natural
The compassA navigational tool that does far more than tell
you the direction of north!
Compasses can be used to take bearings which are used when visibility is minimal or to confirm
the direction of travel
Compass architecture
Transparent baseplate
Compass housing
Roamer
Direction of travel
arrow
Compass bearings• Align the edge of the compass with the start and end point
• Rotate the compass housing until the orienting arrow and lines point N on the map
• Account for magnetic deviation
•Rotate the map and compass together until the red end of the compass needle points north• Follow the direction of travel
arrow
The toolbox so far…We now have a navigational
toolbox containing some useful tools to facilitate navigation
• Maps, colour, shape, scale, grid references, contours, geographical
features
• The compass, compass architecture and compass bearings
A few additional tools
• Handrails
• Aiming off
• Attack points
Handrails
What is a handrail?• A handrail is a linear geographic feature such as a river, stream, fence or ridge
What is ‘handrailing?’• Handrailing is where a handrail is used as a point of reference and hikers walk along a handrail for part of their journey
A very obvious natural handrail!
The arête of Helvellyn formed from glacial erosion
Minor Road
Stream
Coniferous Wood
Using natural, linear handrails
Aiming off •Aiming off is used when walking on a bearing
• You should perform a compass bearing and aim towards a geographical feature that lies on the bearing• When that feature has been
reached another bearing can be taken
Attack points• The geographic feature which you are aiming for is called an ‘attack point’
Linear feature
Attack pointCompass bearing
Aiming off
What makes a successful navigator?
• Where am I? (Position fixing)
• Where am I going to? (Direction finding)
• How do I get there? Or,
“What tools do I have in my navigational
toolbox to enable me to reach the required
destination”
Position fixing
• Setting the map using colour,
symbols, geographic features etc
• Grid references
Aiming off Compass bearings
Destination
Attack Point
Handrailing
Putting it all together
That’s all folks!
More help?
‘Mountain Navigation,’ Peter Cliff (1991)