- Pie charts are often criticised. Comparing the size of pie segments can be difficult, and many visualisation experts suggest that bar-charts should be used instead.
- Using area or volume to represent data can distort data values, and exaggerate differences between values. For example, if the radius of the circle is used to represent data values, the area of the circle will quadruple if the data values double. There is also an issue of 'perceptual scaling' - the tendency of people to underestimate areas.
- When using colours to portray data values or types, ensure that the colors used are accessible to all users. Online tools such as ColorBrewer (www.colorbrewer.org) can help identify issues with colours used.
- Bubble charts can be created in a range of standard data applications such as Excel.
- Some combination charts, such as bar and line charts, can be created in standard applications such as Excel (using more than one axis). Others can be combined by saving visualisations as image files and combining in an image editor.
- Pie charts can be created in a range of standard data applications such as Excel.