Graphical Presentation of Data

What you should know by the end of this lesson:

How to read, interpret, create and evaluate the following types of graphs

Bipolar Analysis

Dispersion Diagram

Data Presentation Workbook

Bipolar Analysis

Purpose:

This is a technique used for comparing areas, people or gathered data. It can be used to visually portray the results of a questionnaire or survey.

Examples:

Advantages

•Large amount of data can be plotted in a small space.

•Patterns can be quickly and easily identified.

Disadvantages

•Results are based on perceptions that may be biased.

•The technique can only be used for two or three areas, otherwise, the graph will be come confusing.

Task 7 Page 14 of your work booklet

Dispersion Diagram

Purpose:

These are used to display the main patterns in the distribution of data. It shows the range of data and the distribution of each piece of data within that range. It, therefore, enables a comparison with the degree of clustering of two sets of data.

Examples:

Advantages

Are easily understood
Give an indication of the reliability of data
Allow the calculation of averages
Anomalies can be shown
Show the spread from the mean

Disadvantages

Data must be in a form that can be placed along a number line
Work better with lots of data
The standard deviation can easily manipulate it and can be biased

Task 6 Page 12 of your work booklet

Kite Diagram

Purpose:

A kite diagram is a chart that shows the number or percentage of something against distance along a transect.

Examples:

Advantages

Clear and easy to interpret
Shows changes over distances
Shows density and distribution of variables

Disadvantages

Not all data can be represented by these charts
Time-consuming to plot by hand
Not an easy computer programme to plot these charts

Task 3 Page 6

Construct a Kite Diagram for the information provided

How to Construct a Kite Diagram

1.Get some graph paper

2.Draw a X-axis showing the distance line

3.Each row needs to be the same scale. Check your results for the most common species to give your widest point.

4.In the centre of each row draw a line for your species.

5.Plot your numbers on either side of the centre line

6.Draw a line to join the dots. Colour in the kite and repeat

Logarithmic Graph

Purpose:

These are used when the values in the scales are so large that they are difficult to show on linear graph paper or when the graph is used to compare the scales of growth. a logarithmic scale increases by multiplication value rather than additions.

Examples:

Advantages

Useful for studying data that change exponentially
Can display a much larger range of data than a linear scale
Allows you to increased detail as smaller values for larger values are compressed

Disadvantages

0 cannot be plotted
Positive and negative always cannot be plotted in the same graph
It's difficult to interpret as scale is distorted

Task 2 Page 4 of your work booklet

Polar Graph

Purpose:

Polar graphs are used to show direction as well as magnitude. They can only be used when the data shows some form of orientation.

They have several practical uses in geography for showing a relationship or correlation between two observed variables, such as:

corries - orientation of corries against altitude or size
vegetation - aspect of a slope against the frequency of vegetation type.

Examples:

Advantages

Useful when one variable is directional
Visual patterns can be identified quickly and easily
Can compare multiple sets of data
Lots of data can be put on one graph and compared

Disadvantages

Only useful with a limited type of data
Hard to make a suitable scale can distort the higher values
Hard to spot anomalies

Task 4 Page 8 of your work booklet

Systems Diagram

Purpose:

Systems diagrams are simplifying devices that can be used to communicate quite complex relationships.

They usually comprise boxed annotations linked by lines or arrows.

They are used to put across concepts and ideas, e.g. the hydrological cycle, the ecosystem or the spiral of unemployment.

Examples:

Advantages

An important tool for planning and laying out at process
Provide an overview of the system
Demonstrate relationship
Convenient method of communication as they are easy to follow and read
Provide logical paths and options

Disadvantages

Requires a lot of planning to ensure all stages are included
Can become complex if too much information is displayed
Take a long time to produce

Task 1 Page 3 of your work booklet

Construct a hydrological cycle systems diagram

Scatter Graph

Purpose:

Scatter graphs are used to show a relationship or correlation between two sets of paired data (variables) - for example, population size and a number of services, distance from the source of a river and average pebble size.

Examples:

Advantages

Large amounts of data can be plotted in a relatively small space
Patterns can be identified quickly and easily
Anomalies can be identified

Disadvantages

Can only be used to display two variables
You can easily make mistakes from plotting large numbers of points
The best fit line may indicate a misleading relationship

Copy out the different types of correleation shown in scatter graphs

Triangular Graph

Purpose:

Triangular graphs are used to show data that can be divided into three parts. This might include data such as soil (sand, silt and clay), employment (primary, secondary and tertiary) and housing (terraced, detached, semi-detached).

Examples:

Advantages

Easy to compare.
3 bits of data can be compared at the same time as they use the same scale (are always out of 100).
By using lots of graphs, comparisons can be made.

Disadvantages

Difficult to construct.
May be wrongly interpreted.
Quite difficult to read – have to have the background knowledge of how to use the graph.

Task 5 Page 10 of your work booklet

Section Complete

Return to Geographical Data Handling

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