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)