Graphs & Diagrams | Geography for GCSE/IGCSE - Year 11 PDF Download

Key terminology

Line graph

• One of the simplest ways to display continuous data
• Both axes are numerical and continuous
• Used to show changes over time and space

• A river cross-section is a specific type of line graph; although it does not represent continuous data, the points can be connected to illustrate the shape of the river channel

Bar chart

• A bar chart is the most basic method for presenting data
• Each bar has uniform width but varying lengths
• Bars are evenly spaced apart
• Suitable for discrete data
• Bar graphs are beneficial for comparing data sets and observing changes over time

Comparing Data

• Comparing classes or groups of data
• Changes over time

Histograms

• Histograms show continuous data
• Always use a ruler to draw the bars
• All bars should be the same width
• The top of the bar should reach the number on the side of the graph that is being represented
• There should be no gaps, all bars should be touching
• Ensure all axes are labelled and that the graph has a title

Compound or divided bar chart

• The bars in divided bar charts are subdivided to represent information, with all bars totaling 100%.
• These charts display a variety of categories.
• They are capable of showing percentages and frequencies effectively.

Histograms

• A histogram is a graphical representation used to display the age-sex distribution of a population.
• It can be utilized to illustrate the structure of a specific area or country.
• Patterns within histograms are easily identifiable.

Pie Charts

• Pie charts are used to represent proportions, where the area of each segment corresponds to the proportion it represents.
• They can also be depicted as proportional circles.
• These charts can be integrated into maps to showcase variations at different locations.
• The total percentage of a pie chart must sum up to 100%.
• To calculate the degrees of each segment in a pie chart (totaling 360°), divide the percentage by 100 and then multiply by 360.
• Each segment in a pie chart should be distinctively colored.

Rose diagram

• Utilize multidirectional axes for plotting data with bars.
• Compass points indicate the axis's direction.
• Applicable for displaying data like wind direction, noise levels, or light intensity.

Triangular graph

• Features axes on three sides, each ranging from 0 to 100.
• Designed for representing data divisible into three parts, usually in percentages.
• Suitable for plotting information such as soil composition, employment distribution, etc.
• Review each side carefully to ensure correct interpretation of data directions.

Scatter graph

• Points in triangular graphs should not be connected. They are individual data points.
• The best fit line can be added to illustrate the relationships between the points.
• Triangular graphs are utilized to depict the relationship between two variables.
  • In a river study, they are particularly useful for illustrating relationships between different river characteristics, such as the width and depth of the river channel.

Types of correlation

Correlation helps us understand the relationship between different variables in data. There are three main types of correlation:

• Positive Correlation: When one variable increases, the other also increases. The line of best fit on a graph slopes from the bottom left to the top right.
• Negative Correlation: As one variable increases, the other decreases. The line of best fit on a graph slopes from the top left to the bottom right.
• No Correlation: When data points are scattered with no clear relationship between the variables.

Choropleth Maps

• Choropleth maps use shading based on a predetermined key.
• Each shade represents a specific range of values.
• It's common to use various shades of a single color.
• These maps are ideal for displaying data like annual precipitation, population density, and income levels.

Proportional symbols map

• Symbols on a map are depicted proportionally to the represented variable.
• Common symbols include circles, squares, or custom images.
• They can effectively showcase diverse data such as population distribution, wind farm locations, and traffic patterns.

Pictograms

• Proportional circles maps are a way of displaying data using symbols or diagrams drawn to scale.
• They are a useful way of representing data when accuracy is not critical and data is discrete.
• Years do not necessarily have to be continuous in these maps.
• Symbols in these maps do not need to be whole but can represent a proportion.
• A key is essential to indicate if the total number of objects or events that an image represents exceeds one.

How to read a pictogram

• Step 1: Carefully read the problem and identify the specific information requested from the pictograph.
• Step 2: Count the symbols corresponding to the desired information and report the count.

• In the illustration above, it is evident that out of 4 shoppers heading to the supermarket, only one opted for a taxi as their mode of transportation.
• The majority of shoppers, as depicted, chose to use a car for their journey to the supermarket.