A diagram is a symbolic representation of information. Infographics typically combine multiple types of visualisations (eg text, illustrations, graphs) in a single graphic. 

Diagrams:

• show concepts or processes such as scale, cross-sections, relationships, simplified maps, or hierarchies of information
• help to communicate a technical or scientific concept.

Infographics:

• can be data, process or message driven, depending on the topic and readership
• show information, statistics and facts quickly and clearly
• appeal to a general audience
• are often self-contained or standalone
• may include animation or interactivity.

This section covers:

• Types of diagrams
• Infographics
• Main conventions for diagrams and infographics
• Functional design for diagrams and infographics.