GEOGRAPHY IGCSE: GRAPH SKILLS. It contains: types of graphs, line graphs, pie charts, bar charts, climate graphs.

1. IGCSE GEOGRAPHY
2. GRAPH SKILLS
TYPES OF GRAPHS
LINE GRAPHS
PIE CHARTS
BAR CHARTS
CLIMATE GRAPHS

2. Different types of graph are used to represent statistical data.
The most common types are:
• line graphs
• bar graphs
• pie charts
Most graphs have two axes:
• the X axis is horizontal (across the bottom)
• the Y axis is vertical (up the left side)
The two axes each represent a different set of data. Line graphs
are drawn by plotting points by their X and Y coordinates, then
joining them together or drawing a line through the middle.

3. The line graph below shows how energy consumption is
expected to rise, while consumption of fossil fuels falls and
the demand for renewable energy increases.

4. Comparison
Sometimes different sets of data will be represented on the
same line graph, so comparisons can be made. This is sometimes
called a comparison line graph.
Compound
If information can be subdivided into two (or more) types of
data - eg total population growth, female population growth
and male population growth - then all three can be drawn on a
compound line graph.
Scatter
Where the points on a graph do not map into a neat line, a line
is drawn through the middle of the points to show the trend or
correlation. This is called a scatter graph.

5. Pie charts are used for showing how something breaks down
into its constituent parts.
Pie charts are usually drawn so the biggest piece of pie comes
first (starting at 12 o'clock).
The 'others' section usually goes last (coming up to 12 o'clock).
If each piece of pie has its percentage written in, it's easier for
the reader to work out the exact proportions.

6. The following pie charts show differences in the split between
primary, secondary and tertiary employment in USA, Brazil and
Nepal.
In this example the circles are the same size.
It would also have been possible to make the size of the circle
proportional to the size of each country's labour market.
Pie charts like this are sometimes called proportional circles.

8. Bar charts or bar graphs represent data as vertical blocks or
columns.
The X axis shows what type of data each column represents,
and the Y axis shows a value for that type of data.
For example, in a rainfall graph, each column on the X axis
represents a month of the year, with the height of each column
on the Y axis showing the amount of rainfall in that month.

9. It is possible to split each column into sections to show the
breakdown of data.
For example, the employment data shown two slides ago could
have been represented as three columns on a bar chart.
The three columns would represent the three countries, with
each column subdivided into sections showing primary,
secondary and tertiary in different colours.
This type of bar chart is called a compound bar chart.

10. It is also possible to compare two sets of data on a bar chart -
for example, measuring rainfall in two countries over the same
period.
This type of bar graph is called a comparative bar graph.
The chart on the next slide compares the tourism data for the
UK in October 2001 with October the previous year.
The graph shows how tourism declined after the terrorist
attack in America in September 2001.

12. Climate graphs are a combination of a bar graph and a line
graph.
Temperature is shown on a line graph, with the figures being
shown on the right side of the graph.
Rainfall is shown by a bar graph, with the figures being shown
down the left side of the graph.
The next climate graph shows average annual rainfall and
temperature throughout the year for a particular area.

14. You may need to look at the information in a graph and
describe the area's climate.

15. Is the temperature the same all year round?
If it is different, how many seasons does the location
experience?
Which season is the warmest?
Is it warm (10 to 20°C), hot (20 to 30°C) or very hot (above
30°C)?
Which season is the coolest?
Is it mild (0 to 10°C), cold (-10 to 0°C) or very cold (below -
10°C)?
What is the range of temperature? (Subtract the minimum
temperature from the maximum temperature).

16. Does the rainfall occur all year round?
What is the pattern of the rainfall?
Check which season(s) is/are drier or wetter than others.
What is the total annual rainfall?
Add each month's total together to get the annual total.
Then put the rainfall and temperature information together -
what does it tell you about this area?

17. Describe the patterns in temperature and rainfall, including
how they relate to each other.
You now have a description of the climate.
Now look again at the climate graph above.
What can you deduce about the climate?