Charts and graphs can be very effective at communicating data, from plotting change over a period of time, to comparing quantity and percentages There are many types of chart and graph: bar charts, line charts, scatter graphs and pie charts to name a few.
Here are a few suggestions to help you make the important data as clear and accessible to as many people as possible:
Design
-
The information contained in a chart or graph is the most important detail and should stand out clearly. In some charts or graphs information will be represented by a directional line, in others it may be symbols or points. Design these features so that they stand out clearly.
-
Data points or symbols will be clearest with adequate space around them.
-
If using a number of directional lines across your chart or graph, you will need to break one line where the other crosses over the top. This will provide a sense of direction and will avoid the lines merging together.
-
The design of many charts and graphs depends on a line work structure such as horizontal and vertical lines. There may also be small tick marks that represent a value. These lines are less important, so they should be lighter than data lines. This will ensure that the data will stand out clearly from the structure of the chart or graph.
-
Ensure symbols used are consistent in design.
-
When designing bar charts, avoid making space between bars the same width as the bars themselves as this can cause uncomfortable visual effects.
Texture and colour
-
Use textures with care to avoid creating uncomfortable visual patterns or shimmering effects that can confuse the eye. Also avoid textures that are too heavy and will dominate the chart or graph.
-
If using colour on a chart or graph, ensure good colour contrast is used. Never use colour alone to convey information such as 'the red line shows distance travelled.' Not everybody can distinguish different colours, so ensure important parts of a chart or graph are labelled.
Text and labelling
-
Use labels only where necessary. Repetitive labels take up space and make the chart or graph appear more cluttered and confusing than it needs to be.
-
Avoid using italic letters as these can be difficult to read.
-
Ensure text is horizontal as much as possible - the only exception to this is labelling the vertical Y axis.
-
If using abbreviations to label a chart or graph, use intuitive letters rather than obscure abbreviations.
-
If a label used contains more than one line of text, ensure the text is left aligned as it will be easier for a person to find the beginning of the next line.
There are computer programs available that will produce charts and graphs. However they may not always produce results that are clear and legible to everybody due to their formatted settings, so some adjustment may be needed.
Always provide a description of the chart or graph in the accompanying text. This will help users find the information they require if they can't access the actual chart or graph.