1. Geography Coursework Aims:
To consider the pros and cons of two graphical methods
To complete part of a past exam question
To be able to construct pie charts and proportional circles
To be able to accurately plot information onto a base map

2. Starter: Data representation
In pairs write down the pro’s and con’s of the following types of data representation:

3. Pros and cons of pie charts:
Good:
visually attractive
shows proportion of components clearly using % totals
shows scale
Bad:
Less than 3 segments look simplistic
If many segments a similar size; it is hard to interpret

4. Pros and cons of Proportional circles
Good
visually attractive
location shown
provide context
show scale
show proportions
Allows comparisons between data sets
Bad
Very hard to calculate
Size may obscure location or mean less accurate positioning on maps, i.e. in cities

5. Constructing Pie Charts

6. June 2010 - Complete the past question

8. Constructing proportional circles
Proportional circles are circles which are drawn in proportion to values that each one is trying to show.
Proportional divided circles are individual pie charts (previous exam question)
They are both particularly useful when comparing different sets of data.

9. Equipment
Base map
Atlas
Ruler
Calculator
Pencil
Compass
Rubber

10. Add Cities
Glasgow
Edinburgh
Aberdeen
Dundee
Inverness

11. Step 1
√ 581320  = Thus:       x   =
City
Population
Square Root
Radius of circle
Glasgow
581,320  
Edinburgh
454,280
Aberdeen
183,030
Dundee
142,220
Inverness
44,220

12. Answers The radius of each circle can be worked out later City
Population
Square Root
Radius of circle
Glasgow
581,320  
Edinburgh
454,280  
Aberdeen
183,030  
Dundee
142,220  
Inverness
44,220  
The radius of each circle can be worked out later

13. Step 2 Draw a scale line to fit all your square root values 100 200
100
200
300
400
500
600
700
800

14. Step 3
At the highest end of the scale draw a circle as big as you can but not too big for the map! – highest value = Its done for you here.
Draw a vertical line representing the radius of the circle
100
200
300
400
500
600
700
800

15. Step 4
Draw a line from the centre of the circle to the far left of the linear scale
100
200
300
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500
600
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800

16. Now using your linear scale draw a line from the base of the scale to the top of the red line for each square root. Your compass can the be set to the correct radius for Glasgow and draw your circle on the base map.
You can then complete radius line for Edinburgh as per my example opposite and set your compass and draw the circle on the base map
Step 5
100
200
300
400
500
600
700
800
The radius for any circle along the linear line can now be found using the same method

17. Here are the radius lines for each city.
Set your compass up in turn for each radius and draw the circles on the base map.
Step 6
100
200
300
400
500
600
700
800
The radius for any circle along the linear line can now be found using the same method. You can measure your radius lines from the scale above add them to the grid
above (only do this if you have time)

18. Step 7
Add the rest of the circles in descending size. Make sure the smaller circles can be seen. Shade in each circle using the same colour for all.
Ad a title for your map.

19. Plenary
Discuss with your partner what type of information would be best represented in
Pie charts
Proportional circles