Visualization Techniques and Practice

Don't use pie charts

You can learn a lot from looking at bad examples as well as good ones.

Visualization is easy, right? After all, it's just some colorful shapes and a few text labels. But things are more complex than they seem, largely due to the the ways we see and digest charts, graphs, and other data-driven images. While scientifically-backed studies do exist, there are actually many things we don't know about how and why visualization works. To help you make better decisions when visualizing your data, here's a brief tour of the research.

This is a comprehensive, but well curated list of resources for data storytelling.  Worth a deep dive or two

The deck from Gregor Aisch's workshop on data visualization.  This 176 slide powerpoint deck goes through why and how to select particular types of charts.   Practical advice on color and use of maps too.

Chart advice particularly useful:

• Avoid 3d-charts at all costs. The perspective distorts the data, what is displayed ‘in front’ is perceived as more important than what is shown in the background.
• Use pie charts with care, and only to show part of whole relationships. Two is the ideal number of slices, but never show more than five. Don’t use pie charts if you want to compare values (use bar charts instead).
• Always extend bar charts to zero baseline. Order bars by value to make comparison easier.
• Use line charts to show time series data. That’s simply the best way to show how a variable changes over time.
• Avoid stacked area charts, they are easily mis-interpreted.
• Prefer direct labeling wherever possible. You can safe your readers a lot time by placing labels directly onto the visual elements instead of collecting them in a separate legend. Also remind that we cannot differentiate that much colors.
• Label your axes! You might think that’s kind of obvious, but still it happens quite often that designers and journalists simply forget to label the axes.
• Tell readers why they should care about your graphic. Don’t waste the title line by just saying what data is shown.

What chart should I use? 

From a presentation at data journalism conference by Alberto Cairo

http://journalisminteractive.com/2013/live-blog-the-functional-art-design-and-infographics/

Some good photo/smart phone tips. It also talks about how to visually brand your social channels ...