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Map Reading & Navigation. Prepared by: The Expedition Company Limited. Introduction. This clear and simple tool is designed to provide you with the basic skills with which to learn to map read.

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map reading navigation
Map Reading & Navigation

Prepared by: The Expedition Company Limited

introduction
Introduction

This clear and simple tool is designed to provide you with the basic skills with which to learn to map read.

Using a step by step process, you can progress comfortably at your own pace, with practical exercises and illustrations in every section to help you learn.

Prepared by: The Expedition Company Limited

equipment
Equipment

Equipment requirements are simple.

You will need a:

Ordnance Survey Map

Silva Compass

Sharp pencil

Plain Paper

Fine String

Prepared by: The Expedition Company Limited

course content
Maps

A brief History

Components

Type/Scale

Symbols

Plotting a location

Measuring distance

Relief

The Compass

Components

North

True

Grid

Magnetic

Map & compass work

Course Content

Route Planning & Safety

Prepared by: The Expedition Company Limited

slide5
Definition

Map .noun. Flat representation of the earth or some part of it with its physical or political features or of the heavens

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history

History

Ever since man has been able to write and draw there is evidence to also show that he has recorded routes on land and sea.

Where maps were originally shown on clay tablets and papyrus, we can now display them on paper and even CD Rom!

Prepared by: The Expedition Company Limited

the ordnance survey map
The Ordnance Survey Map

Ordnance Surveymaps come in a variety of different formats and this guide will show you how to choose which one is best suited for your own use.

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types of map the importance of choosing the right map
Types of MapThe importance of choosing the right map.

Prepared by: The Expedition Company Limited

symbols
Symbols

We interpret both man made and natural features on the map, through a system of symbols.

Every Ordnance Survey map has a key showing the definition of each symbol to help you. We will look at a few of the more common symbols.

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symbol examples
Symbol examples

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symbol examples1
Symbol examples

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grid lines
Grid lines
  • Every Ordnance Survey map is covered in a series of grids.
  • By learning to use these grids we are able to locate a particular point on a map.

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distance
Distance
  • Grid lines on all Ordnance Survey Maps are spaced 1km apart, regardless of scale.
  • This makes it easy to judge the rough distance between points by counting squares.

1.5 km

1 km

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grid lines1
Grid Lines

52

52

Horizontal Lines = Northings

63

64

65

66

51

51

50

50

Vertical Lines = Eastings

49

62

63

64

65

66

reading a grid reference
Reading a Grid Reference
  • Grid references should be read in the following order:
    • Eastings - Along the Corridor
    • Northings - Up the Stairs

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slide16
Plotting a Grid Square

52

52

63

64

65

66

51

51

Stairs

The

50

50

& Up

Along the Corridor

49

62

63

64

65

66

slide17
Plotting a Grid Square

52

52

63

64

65

66

51

51

Grid: 64 50

50

50

49

62

63

64

65

66

accurate plotting
Accurate Plotting
  • Having plotted the grid Square (1km x 1km) you will often need to establish the accurate location of a point or feature within the Square.
  • This is achieved by dividing the square into a further ten Eastings (Vertical lines) & Northings (Horizontal lines).
  • These additional lines are read in exactly the same manner as before.

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accurate plotting one grid square
Accurate Plotting(One Grid Square)

1 km

0

9

8

7

6

5

1 km

4

3

2

1

50

0

0

1

2

3

4

5

6

7

8

9

0

64

measuring distance
Measuring Distance

By using the scale at the bottom of each Ordnance Survey Map you can easily convert a measurement in centimetres into a real distance on the ground.

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measuring distance using a silva compass
Measuring Distanceusing a Silva Compass

Nearly all compasses have a centimetre scale which proves an effective tool for measuring the distance between two points.

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measuring distance using a piece of string
Measuring Distanceusing a Piece of String
  • Trace your route on the map with a piece of string and mark the points at which the route starts and finishes on the string.
  • Place the string against the scale on the map and read off the equivalent distance on the ground.

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measuring distance using a map measurer
Measuring Distanceusing a Map Measurer
  • Map measurers are purposefully designed for measuring distances on a map.
  • Trace your route with the small wheel at the bottom of the measurer and it will automatically tell you the distance on the ground via a rotating scale.

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relief
Relief
  • Relief refers to the way in which height is displayed on a map.
  • This is shown by a system of lines called‘Contours’.

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contour lines
Contour Lines
  • Contour lines link points of equal height on the map at ten metre intervals.
  • Contours display how many metres land is above sea level.

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slide27
Definition

Compass .noun. Instrument showing user the direction of north and other points of the ~ by means of magnetic needle

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the compass
The Compass

There are a variety of different compass styles available to you. We suggest that to begin with, you use a Silva compass similar to the one pictured here.

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the compass1
The Compass
  • They were originally discovered by the Chinese 5000 years ago.
  • They are made in a variety of forms for use on land, above and below the sea and in the air.
  • Examples of activities in which they are used are:
    • Hillwalking - Mountaineering
    • Cycling - Surveying
    • Driving - Military
    • Sailing - Scuba Diving
    • Flying - Orienteering

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cardinal points compass points
Cardinal Points (Compass Points)

North

0º & 360º

North West : 315º

North East : 45º

West

270º

90º

East

South West : 225º

South East : 135º

180º

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South

bearings are taken in degrees the cardinal points are divided up into 360 measured clockwise
Bearings are taken in degreesº- The cardinal points are divided up into 360º & measured clockwise.

North

0º & 360º

North West : 315º

North East : 45º

West

270º

90º

East

South West : 225º

South East : 135º

180º

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South

parts of the compass
Parts of the Compass
  • The compass can be broken down into various components.
  • We will look at each component separately to define its use.

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base plate compass housing
Base Plate & Compass Housing
  • The Base Plate is the mounting for the housing and displays a variety of information eg. Scale ruler.
  • The Compass Housing contains a magnetic bar, called the Needle and defines the points of the compass on a rotating bezel.

CompassHousing

Base Plate

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the compass needle
The Compass Needle

Needle

  • The needle is suspended in liquid which enables it to move freely, always settling with the red end pointing North.
  • Some needles are Luminous to help navigation in the dark.

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direction of travel arrow
Direction of Travel Arrow
  • The Direction of Travel Arrow indicates the direction along which you wish to travel or take a bearing.
  • The arrow is fixed within the base plate.
  • The sides of the base plate run parallel to the arrow.

Direction of Travel Arrow

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the index line
The Index Line

Index Line

  • The Index Line is a fixed line within the Compass Housing and is in line with the direction of travel arrow.
  • The Index Line marks the bearing you set by rotating the bezel.

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orienting lines
Orienting Lines
  • These are displayed within the rotating Compass Housing and are designed to be aligned parallel with the Eastings on a map.
  • The orienting lines on some compass models show one half of the lines in red to depict north.

Orienting Lines

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compass scale
Compass Scale
  • Nearly all compasses have a centimetre scale along the edge of the base plate to enable you to measure distances.
  • Used in conjunction with the scale at the bottom of the map, the compass scale enables you to calculate the distance on the ground.

Compass Scale

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points to note
Points to Note
  • Stand clear of metal objects when using the compass. They will cause the needle to deviate and create inaccurate bearings. Objects as small as watches can make a difference.
  • Hold the compass as flat as possible to allow the needle to move freely.
  • Look after your compass - try to avoid dropping or knocking it.
  • Store away from other compasses and electrical equipment.
  • Your compass may need replacing if a large air bubble forms in the Compass Housing.

Prepared by: The Expedition Company Limited

true grid magnetic north
True / Grid / Magnetic North
  • True Northand South are at the geographical poles.
  • Grid Northis the direction to which all Ordnance Survey Maps are oriented. We take our map bearings using Grid North.
  • Magnetic Northis the direction a compass points to and in the UK it is located approximately 5º West of Grid North.
magnetic variation
Magnetic Variation

True North

  • The difference in degrees between Magnetic (Mag)North and Grid North is referred to as the Magnetic Variation (usually 5º West in UK.)

Grid North

Magnetic North

magnetic variation1
Magnetic Variation

True North

  • It is important to understand the relationship between Grid & Mag north as this will become important when we start to convert bearings to and from a map.

Grid North

Magnetic North

map compass work
Map & Compass Work
  • Having looked separately at both the Ordnance Survey Map & Silva Compass the following example will demonstrate how they are used together.
  • If you are unsure about anything which has been covered in the previous slides, look back now before you progress to the next section.
map compass work1
Map & Compass Work
  • When working from the map we deal with Grid Bearings.
  • When following a compass on the ground we work with Magnetic Bearings.
  • There is a simple system which enables us to convert Grid to Mag and Mag to Grid.
  • The system refers to whether we add or subtract the magnetic variation to convert the bearing.
map compass work2
Map & Compass Work

Mag to Grid…………. GET RID

Grid to Mag………….ADD

(usually 5º West in UK)

map to ground
Map to Ground

Grid to Mag………….ADD

map to ground1
Map to Ground
  • Select a start and finish point on the map.
  • Line up the edge of the compass with the line along which you intend to travel.
  • Keeping the base plate static - rotate the compass housing until the orienting lines are parallel with the Eastings and the red ‘N’ is pointing to North on your map.
map to ground2
Map to Ground
  • Read the bearing shown on the housing from the index line.
  • Remember - Grid to Mag……Add.
  • Add the magnetic variation shown at the top of the map (usually 5º West in UK.)
  • You now have your magnetic bearing of the course you have chosen. The next step is to orientate yourself.
orientating
Orientating
  • Hold your compass level and steady.
  • Turn your body until the red end of the needle is in line with the Red ‘N’ on the Housing.
  • The direction of travel arrow is now pointing along the route you chose from the map and you are ready to travel.
following the compass bearing
Following the Compass Bearing
  • Hold your compass level and steady.
  • Ensure that the red end of the needle is in line with the Red ‘N’ on the Housing every time you refer to the compass bearing.
  • Follow the direction of travel arrow. You will find it easier to line up the direction arrow with a physical feature on the ground (eg tree, pylon, tower). Use this as a reference point which you can move towards. This is easier than following the compass every inch of the way.
ground to map
Ground to Map

Mag to Grid…………. GET RID

ground to map1
Ground to Map
  • Select the feature on the ground to which you wish to take a bearing.
  • Hold the compass steady and level.
  • Point the direction of travel arrow at the feature.
  • Rotate the housing until the red end of the needle is in line with the Red ‘N’ on the Housing.
ground to map2
Ground to Map
  • This is your Mag bearing which you can either travel along or convert to a grid bearing.
  • To plot on the map you should first locate your own position and mark it.
  • Convert the Mag bearing to a Grid bearing by Mag to Grid……Get Rid. (Usually 5º West in UK.)
  • Subtract the magnetic variation.
ground to map3
Ground to Map

Place the compass on the map and keeping the bearing set on the housing, rotate the whole compass until the orienting lines are parallel to the Eastings on the map. The edge of the compass should run through your position and show the bearing on the map.

ground to map4
Ground to Map

By turning your body until the red end of the needle is in line with the Red ‘N’ on the Housing you have now oriented yourself and the map.

quick orientation
Quick Orientation

You can orientate yourself and the map to the ground at any time using this easy system:

A. Lay the compass on the map.

B. Line the edge of the compass and the orienting lines up with the Eastings.

C. Turn your body until the red end of the needle is in line with the Red ‘N’ on the Housing.

You and your map are now facing North.

route planning
Route Planning
  • It is important, where possible, to take time in planning your route before you start.
  • This will help you to identify any problems early and to estimate how far you intend to travel and how long it should take.

Prepared by: The Expedition Company Limited

route card
Route Card
  • A route card is simple to produce and makes navigation on the ground simple. A basic format is shown here:

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route planning safety
Route Planning & Safety
  • Make sure that your route is well within your ability and that you are in possession of the right equipment.
  • Leave a copy of your route card with a friend or contact in order that you can be easily found in an emergency.

Prepared by: The Expedition Company Limited

map reading navigation1
Map Reading & Navigation

Prepared by: The Expedition Company Limited

slide61
Ordnance Survey

Romsey Road

SOUTHAMPTON

United Kingdom, SO16 4GU

www.ordsvy.gov.uk

produced in association with
Produced in association with

The Expedition Company Limited

Po Box 17

Wiveliscombe

Taunton, TA4 2YL

Tel: +44 (0) 1984 624780 Fax: +44 ()) 1984 629045

email: [email protected] Web: www.expedition.co.uk

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