Unit 2: Geographical Skills

Reminder! An overview of Unit 2

• Worth 30% of your AS

• 1 hour exam on Friday 15th May

• Total of 50 marks

• Questions on skills (part 1) and your fieldwork investigation (part 2)

You will need the following equipment in the exam:

• Rubber• Ruler• Protractor• Compasses• Calculator

Graphical skills

In the next few lessons we will cover the following graphical skills:

• Line graphs: simple, comparative, compound and divergent

• Pie charts• Proportional divided circles• Triangular graphs• Radial diagrams

Line graphs are used to show continuous data.

Simple line graphs are used for showing the

relationship between two variables.

One of these variables is usually time but they can also show other factors.

For example, the relationship between

temperature and altitude.

Line graphs

Line graphs

% of species cover on a sand dune

0

10

20

30

40

50

Site 1 Site 2 Site 3

Site

% o

f co

ver Lyme Grass

Marram Grass

Sea Spurge

Ragwort

ComparativeTwo or more sets of data to compare

Line graphs

CompoundShows different

proportions of the total.

Line graphs

DivergentThese are used when one set of data

is provided for part of the period under consideration and then this

data set is split into separate components for another part of the

period.

DivergentAlso when a graph displays

positive and negative values.

Line graph activity

Go to the June 2010 paper in your exam question booklet:

1. Answer Qu. 1 (a) (i)

2. Answer Qu. 1 (a) (ii)

Pros Cons• It is easy to read.

• A broken scale can be used when the data starts at a large number. 

• Shows specific values of data.

• Shows patterns in data clearly, meaning that they visibly show how one variable is affected by the other as it increases or decreases.

• Enable the viewer to make predictions about the results of data.

• You can change the way the data of a line graph appears, by not using consistent scales on the axis.

• Used with continuous data only.

• Unsuitable if there are only a few data points.

Pros and cons

Pie charts

Site 1

Lyme Grass

Marram Grass

Sea Spurge

Ragwort

Lyme Grass

Site 1

Site 2

Site 3

Pie charts are used to show how something is divided into shares or percentages of a whole.

The pie chart is useful to show the total data divided into proportions.

It often has good visual impact but it can be difficult to read the data accurately, particularly

if there are several categories.

The segments should be drawn from the largest first and the smallest last unless there is an

"others" category in which case that should be last regardless of its size.

Segments should be shaded in different colours and a suitable key or labels added.

The raw data and percentage figures can be added to the key if appropriate.

Proportional pies use the concepts of pie

graphs and proportional symbols

together.

The diameter of each pie is proportional to

the total.

This method integrates data together and involves a spatial

element when plotted on a suitable base

map.

Proportional pie charts

Pie chart activity

Go to the June 2010 paper in your exam question booklet:

1. Answer Qu. 1 (b) (i)

2. Answer Qu. 1 (b) (ii)

Do you remember

how to draw pie graphs?

Pros Cons• Displays relative proportions of multiple

classes of data size of the circle

• Can be made proportional to the total quantity it represents

• Summarises a large data set in visual form

• Visually simpler than other types of graphs

• Permits a visual check of the reasonableness or accuracy of calculations

• Requires minimal additional explanation

• Easily understood due to widespread use in business and the media

• Does not easily reveal exact values

• Many pie charts may be needed to show changes over time

• Fails to reveal key assumptions, causes, effects, or patterns

• Easily manipulated to yield false impressions

Pros and cons

Graphical skills

In the next few lessons we will cover the following graphical skills:

• Line graphs: simple, comparative, compound and divergent

• Pie charts • Proportional divided circles • Triangular graphs• Radial diagrams

Triangular graphs

Triangular graphs have three axes.

They are used to show data which is in

percentage form, where each 100% is divided into

three variables.

Once the graph is completed, the variation

between the different sets of data can easily be

seen.E.g. Percentage of a country’s workforce employed in primary, secondary and tertiary industry.

Triangular graphs: step-by-step

Label the axis with the three % variables: • Primary• Secondary• Tertiary

Primary

Secondary

Tert

iary

Primary

Secondary

Tert

iary

You will plot the three sets of data using each axis… you must follow the line in the correct ‘direction’!

Data should always be plotted at a 60° angle.

Use a protractor to work it out… place it on the ‘0’ of each axis and follow the 60° line.

If you can’t remember the direction, just check with a protractor!

Primary

Secondary

Tert

iary

County A Country B

Country C

Primary 60 50 31

Secondary 10 35 14

Tertiary 30 15 55Prim

ary

Secondary

Tert

iary

Primary

Secondary

Tert

iary

County A Country B

Country C

Primary 60 50 31

Secondary 10 35 14

Tertiary 30 15 55Prim

ary

Secondary

Tert

iary

Primary

Secondary

Tert

iary

County A Country B

Country C

Primary 60 50 31

Secondary 10 35 14

Tertiary 30 15 55Prim

ary

Secondary

Tert

iary

What does the graph

show?

Pros Cons• Clearly displays the proportional

balance between 3 variables.• The change in the 3 variables over

time can be seen if variables are plotted for different times.

• Several sets of data can be plotted on one graph.

• Clear visual impression of the dominant variable.

• Summarises data for a large group set much more effectively than in many bar or pie charts.

• Points which have similar characteristics are located in clusters on the graph so they can then be classified.

• Only 3 variables can be plotted.

• Figures must be in the form of percentages.

• Can you think of any more?

• Figures must add up to 100%

Pros and cons

Triangular graph activities

1. Complete the ‘type of service’ worksheet.

2. Plot a few of the countries on the ‘workforce’ worksheet.

Radial (rose) diagram

Radial diagrams are a type of graph where values extend out from a central point; therefore they show the relationship of each variable to the central

point/item.

They are particularly useful when one variable is directional

and uses the points of a compass, or cyclical (e.g. time).

Often used to show flow of people or traffic over a period

of time, in which the circle represents a clock face.

Pros and cons

Pros Cons

• They are advantageous because trends in the data set are clearly shown, with the variable with the largest value being highlighted on the graph.

• The data that is applicable to this method is limited.

• It can also be hard to read exact values from the scale on the axis, as it often makes the diagram too crowded to include the scale.

• Data often has a wide range of values when plotting a number of different variables, meaning that it can be hard to find a suitable scale to use.