Graphs (Cambridge (CIE) IGCSE Geography): Revision Note

Key terminology

Types of data

• Continuous data is numerical data that can take any value within a given range, e.g. heights and weights

• Discrete data is numerical data that can only take certain values, e.g. shoe size

• Quantitative data is where the results can be expressed using numerical values

• Qualitative data is where the results can’t be expressed as numbers, e.g. opinions

Line graphs

• One of the simplest ways to display continuous data

• Both axes are numerical and continuous 

• Used to show changes over time or space

Example

• A river cross-section is a particular form of line graph because it is not continuous data, but the plots can be joined to show the shape of the river channel

Radial graphs

• Use multidirectional axes to plot data with bars or lines

Climate graphs

• A climate graph shows mean monthly temperatures and precipitation rates over 30 years

• They can be local, national, or global  

• Precipitation is always shown as a bar graph and temperature as a line graph

Dispersion graphs

• Dispersion graphs are used to compare sets of data 

• They also illustrate whether the data forms groups or is dispersed (spread)

• Values are shown on the vertical axis

• Can also be used to present the upper and lower values along with the mean, median, mode and extreme values

Doughnut graphs

• Doughnut graphs visually represent proportions as part of a whole

• They are similar to a pie chart but with no centre

Kite graphs

• Kite diagrams can show both distribution and amounts

  • The distribution along a transect is shown by its position along a line in each section of a kite diagram

    • Each section represents a different species 

    • The distance along the transect is given on the x-axis

  • The numbers are shown by the width of the 'kite' around the central horizontal line

    • The shape is referred to as a kite because it extends an equal distance on each side of the central horizontal line

Triangular graphs

• Triangular graphs have axes on three sides, all of which go from 0 to 100

• Used to display data which can be divided into three

• The data must be in percentages 

• Can be used to plot data such as soil content, employment in economic activities

Scatter graphs

• Used to show the relationship between two variables

  • In a river study, they are used to show the relationship between different river characteristics such as the relationship between the width and depth of the river channel

• The points on a scatter graph should not be connected

• The best-fit line can be added to show the relationship