Data Visualization Guidelines (selection)

Design process

• Iterate over your designs, get feedback

Visualization design

• A chart must be as simple as possible, but not simpler.
• Rainbow color maps are harmful
• Don’t use piecharts
• Correspondence principle: The same data should produce the same visualization
• Maxime data-ink ratio
• Overview first, zoom and filter, detail on demand (Shneiderman’s Information seeking mantra)
• Use interaction in visualization sparsely and cautionsly
• Don’t use more than six colors together
• Reduce clutter in Parallel coordinates by reordering axes
• Use adjacency matrices for dense networks
• Chose your colors for various types of color-blindness as well as printed in black+white
• Use several complementary visualizations to reduce clutter and complexity
• Avoid overuse of texture
• Highlight and label missing data
• Focus on the patterns in your data

Communication & presentation

• Message first, visualization design second.
• Don’t truncate axes
• Label your charts and axes
• Avoid overlapping labels and other occlusions
• Chose meaningful scales
• Add meaningful annotations carefully.
• Lie factor guideline: The representation of numbers, as physically measured on the surface of the graphic itself, should be directly proportional to the quantities represented.
• Don’t use the blow-appart effect
• Introduce and explain your visualization
• Know your audience
• Chose a meaningful chart type
• Avoid redundant information and redundant visual encodings
• Avoid 3D effects and encoding data in 3D volumes
• Careful embellishment can improve memorization if related to the patterns in the data
• Use line charts for continuous (e.g., temporal) values only
• Avoid circular charts
• Rely on simple and well-known visualization unless you have a reason
• Long lines are difficult to follow.
• Take advantage of the space you have available (Alberto Cairo)
• visualizations should not simplify messages, they should clarify them (Alberto Cairo)
• think of stucture firs, eye candy later (Albero cairo)
• organize your graphic ino layers: summary/intro, information, logical order
• Experimenting (carefully) with novel foms is not just a whimisical impulse, its a necssity (Albero Cairo)
• the more novel a visalization is,the more redundancy should be included (Albero Cairo)