Maps (Cambridge (CIE) O Level Geography)

Maps

• Questions in the exam will be based on topographical maps 

  • The maps can be from anywhere in the world

  • Maps will have a key, scale, northings and eastings

  • These all need to be used to answer the questions

Grid references

• 4-figure are used to locate specific grid squares within the map

  • The first two figures are the eastings which indicate how far east or west a grid is across the map

  • The second two figures are the northings which indicate how far north or south a grid is on the map

• 6-figure grid references are used to locate exact points within grid squares

  • The first three figures are the eastings 

  • The second three figures are the northings

• To find a 4 and 6 figure grid reference

  • First, find the four-figure grid reference by giving the number from the bottom of the map first and then the number from the side of the map. 

4 - figure grid reference

• In image above the 4-figure grid reference would be 17, 51

• To give the 6-figure grid reference you need to image that the grid square is divided into 100 smaller squares 

Scale 

• Maps in the exam will either be scale 1:25,000 where 1 cm on the map = 25,000 cm (250 m) in real life or 1:50,000 where 1 cm =50,000 cm (500 m) in real life

• When the distance is straight or almost straight it can either be measured using a ruler or the edge of a straight piece of paper.

• Using the scale at the bottom of the map mark distances are marked on a piece of paper.

• This can then be laid from the first point to the second point to calculate the distance.

Using scale to measure a straight line

• A distance along a curved route can be divided, the paper rotated and marked in stages to calculate the full distance

• To measure from A to B following the road on the map below the route can be divided into a series of straight sections using crosses.

• The plain piece of paper can then be used to measure from A to the first cross. It should then be rotated, pivoting at the cross to mark the second cross. 

Measuring a Curved Route

Bearings

• Directions on a map should always be given using compass points

• There are 16 compass points 

Sixteen Compass Points

• A grid bearing is measured from grid north at 0^o, East is 90^o, South is 180^o  and West is 270^o

• Grid bearings are given using a protractor

  • The 0^o should be pointing north and the centre of the protractor on the place the bearing is been given from

  • The compass direction and grid bearing from the crossroads at A to the location at B

• On the map below B is South West of A 

• The bearing is 280^o

Height

• Height can be shown in three main ways;

  • Spot height

  • Contour lines

  • Trigonometrical stations

• Spot heights show the height at a specific point with the height measurement written next to it

• Contour lines are isolines. They join points of equal height and are usually at 5 or 10 meter intervals (distance between the contour line)

  • This means that the height of the land increases by 5 or 10 meters between the lines

• Trigonometrical station is marked by a small black triangle with a height measurement written next to it

Topography 

• The contour lines can also indicate the shape and slope of the land or topography

• Contour lines close together indicates steep land

• Contour lines very far apart indicates gently sloping or flat land dependent on the distance apart

• V-shaped valleys have a v-shaped set of contours 

• A hill is shown by a set of circular contour lines

Contour lines 

Cross-sections

• A cross-section is a slice through the landscape

• They are represented on a map by a line which is often labelled A at one end and B at the other

• They use the contour lines to determine the height of the land

Cross-section on a map

• A piece of paper is then laid along the line and points A and B are marked on

• The contour lines are then marked on each time they cross the paper

Marking on the contour lines

• These figures can then be used to create the cross-section 

Key

• Maps can be used to identify a range of landscape features

• These may be physical and human features

• Each map has a key to show what the symbols mean

Example of a Map Key