Presenting Data: Charts and Graphs

Once you have collected your fieldwork data, the next step is to present it in a clear and effective way. Good data presentation makes patterns, trends and anomalies visible at a glance, allowing you to move on to meaningful analysis. Poor presentation obscures your data and makes analysis difficult.

In the Edexcel B exam, you may be asked to draw a graph or chart from given data, describe what a graph shows, interpret patterns, or evaluate whether a particular graph type was the best choice. This lesson covers all the key chart and graph types you need to know.

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Choosing the Right Graph

The type of graph you choose depends on the type of data and what you want to show. Choosing the wrong graph type is a common mistake that costs marks in the exam.

Graph Type	Best For	Data Type	Example
Bar chart	Comparing discrete categories	Categorical / Discrete	Comparing pedestrian counts at 5 locations
Line graph	Showing change over time or distance	Continuous	River velocity at different distances downstream
Scatter graph	Showing the relationship between two variables	Continuous paired data	Pebble size vs distance downstream
Pie chart	Showing proportions of a whole	Categorical (percentages)	Land use composition of an area
Histogram	Showing the distribution/frequency of continuous data	Continuous grouped data	Distribution of pebble sizes
Compound bar chart	Comparing compositions across categories	Categorical with sub-categories	Land use types at different sites
Population pyramid	Showing age-sex structure	Demographic data	Population structure of an area
Climate graph	Showing temperature and precipitation over a year	Climate data	Monthly temperature and rainfall for a location

flowchart TD
    A["What do you want to show?"] --> B{"Comparing categories?"}
    B -->|"Yes"| C["BAR CHART"]
    B -->|"No"| D{"Change over time<br/>or distance?"}
    D -->|"Yes"| E["LINE GRAPH"]
    D -->|"No"| F{"Relationship between<br/>two variables?"}
    F -->|"Yes"| G["SCATTER GRAPH"]
    F -->|"No"| H{"Proportions of<br/>a whole?"}
    H -->|"Yes"| I["PIE CHART"]
    H -->|"No"| J{"Distribution /<br/>frequency?"}
    J -->|"Yes"| K["HISTOGRAM"]

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Bar Charts

Bar charts display data as rectangular bars where the height (or length) of each bar represents the value. They are the most versatile and commonly used graph type in GCSE Geography.

Rules for Drawing Bar Charts

1. Bars must be the same width and separated by equal gaps
2. The y-axis (vertical) must have a scale that starts at zero and increases in equal intervals
3. The x-axis (horizontal) shows the categories
4. Each bar should be labelled or a key provided
5. Include a title that describes what the graph shows
6. Include units on the axes

Types of Bar Charts

Type	Description	Use
Simple bar chart	One bar per category	Comparing single values across categories
Compound (stacked) bar chart	Bars divided into segments	Showing composition within each category
Divided percentage bar chart	Bars of equal height divided into percentage segments	Comparing proportional composition
Grouped bar chart	Two or more bars side by side for each category	Comparing multiple datasets

Exam Tip: When describing a bar chart, always: (1) identify the highest and lowest values, (2) describe the overall pattern or trend, (3) quote specific data from the graph, and (4) note any anomalies. For example: "Site A had the highest pedestrian count at 127 people in 10 minutes, while Site E had the lowest at 23. There is a general decrease in footfall with distance from the High Street."

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Line Graphs

Line graphs show how a variable changes along a continuous scale — typically time or distance. Data points are plotted and connected with straight lines.

Rules for Drawing Line Graphs

1. The x-axis shows the continuous independent variable (time, distance)
2. The y-axis shows the dependent variable being measured
3. Both axes must have equal intervals and be labelled with units
4. Data points should be plotted accurately and connected with straight lines (not curves, unless specifically told otherwise)
5. If showing multiple datasets, use a key with different colours or line styles
6. Include a clear title

When to Use Line Graphs

• River velocity at different distances downstream
• Temperature change throughout the day
• Pedestrian counts at different times of day
• Beach gradient at different distances from the shoreline

Exam Tip: Be careful not to confuse line graphs with scatter graphs. A line graph connects data points in order (usually time or distance). A scatter graph plots paired data points without connecting them, and you may add a line of best fit.

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Scatter Graphs

Scatter graphs (or scatter plots) show the relationship between two variables. Each data point is plotted using coordinates from the two variables, but the points are not connected.

What Scatter Graphs Show

Pattern	Name	Description	Example
Points rise from left to right	Positive correlation	As one variable increases, the other increases	Distance downstream vs river discharge
Points fall from left to right	Negative correlation	As one variable increases, the other decreases	Distance downstream vs pebble size
Points scattered randomly	No correlation	No clear relationship between the variables	Pebble size vs wind speed

Lines of Best Fit

A line of best fit is a straight line drawn through the scatter of points to show the general trend:

• It should have roughly equal numbers of points above and below the line
• It does not need to pass through the origin (0,0) unless the data suggests it should
• It should represent the general direction of the data
• Anomalies (outliers) should be ignored when drawing the line

Describing Scatter Graphs

When describing a scatter graph, comment on: