Exploring distance time graphs
Exploring distance time graphs

This free course is available to start right now. Review the full course description and key learning outcomes and create an account and enrol if you want a free statement of participation.

Free course

Exploring distance time graphs

1.3 Time-series graphs

1.3.1 Introduction

The time-series plot is the most frequently used form of graphic design. With one dimension marching along to the regular rhythm of seconds, minute, hours, days, weeks, months, years, centuries, or millennia, the natural ordering of the time scale gives this design a strength and efficiency of interpretation found in no other graphic arrangement.

(Tufte, E. (1983) The Visual Display of Quantitative Information, Graphics Press, Connecticut, p. 28)

Graphs which show how a measured quantity varies as time changes are called time-series graphs. In a time-series graph, the horizontal axis represents the ‘regular rhythm’ of time in appropriate Units and the vertical axis represents the quantity that varies over time.

Time-series graphs are favourites of the media, particularly newspapers. They are useful tools of comparative analysis, and are frequently used in support of particular arguments.Figure 1 comes from an article in a national newspaper relating changing levels of crime and drug abuse; Figure 2 appeared in an article critical of the government and shows the changing support (in 1995) for the three largest political parties in the UK; Figure 3 was found on the financial pages of a newspaper – it shows how exchange rates and stock market prices varied over three months.

Figure 1
Figure 1 Crime and drug abuse
Figure 2
Figure 2 Support for political parties
Figure 3
Figure 3 Financial indicators

Time-series graphs should not be looked at in isolation from the context in which they appear. If a graph appears in a newspaper article, for example, it usually has a very specific role to play in supporting the argument being put forward by the writer. Remember that someone has chosen to include that particular graph; someone has chosen how the graph should look; and someone has chosen what information should be included on the graph and what should be ignored. Like the text in which it is embedded, the time-series graph does not appear by accident. It is there to reinforce visually the story the author wants to tell.

One use of time-series graphs is to keep track of how a quantity is changing so that an assessment or prediction can be made. In health care, for example, graphs of how a person’s temperature varies with time can give indications both of the general health of the individual and act as a guide to specific physiological events.


Take your learning further

Making the decision to study can be a big step, which is why you'll want a trusted University. The Open University has over 40 years’ experience delivering flexible learning and 170,000 students are studying with us right now. Take a look at all Open University courses.

If you are new to university level study, find out more about the types of qualifications we offer, including our entry level Access courses and Certificates.

Not ready for University study then browse over 900 free courses on OpenLearn and sign up to our newsletter to hear about new free courses as they are released.

Every year, thousands of students decide to study with The Open University. With over 120 qualifications, we’ve got the right course for you.

Request an Open University prospectus