When I first got into dataviz, I had no idea how many types of charts there were in the world. Choosing a chart is one of the most exciting activities in the field of data design. But it can be overwhelming and nerve-wracking. What if I pick the wrong chart? What chart is best to tell my story? In this article, I wrangle all the chart-type authorities into one place. If you don't already have these bookmarked, I recommend adding them to your stable!
I love how the same type of chart can be used for the most serious business analytics or for trivial (but important) fun like this ultra deep visual analysis of the characters and episodes of Seinfeld.
There are many educational websites out there to help you choose a chart, but these five online chart libraries are exceptionally well-organized and keep me coming back:
Quick summary
The Data Visualisation Catalogue is extensive and very helpful, cross-referencing the charts with what tools and programs can be used to generate them. Many even have explanatory videos of the charts. Bonus points for arranging them in alphabetical order!
DataViz Project has the most beautifully designed chart library. It also has the most chart varieties at 160 and counting, including some way-out there ones I'd never before seen like "Y-Shaped Matrix Diagram". I had fun exploring their many real-world examples for each chart type. I do wish the charts were arranged alphabetically though.
Datylon is an Illustrator plug-in that creates a wide array of chart types from within the program. Their blog explaining 80 different chart types will get you familiar with graphs of all types and includes real-world samples of each which is often the best way to learn.
Visual Vocabulary is a downloadable poster. It's more news and financial-oriented, which makes sense considering it's from the Financial Times.
Chartopedia seems especially oriented toward business and workflow applications.
Among these five sites, it's interesting to note the variation in terminology and categorization. Between them all, I learned there can be multiple names for the same chart and different approaches to categorization. There is no one authority!
For example, the Data Visualisation Catalogue makes a distinction between a "dot matrix chart" and a "pictogram chart." At Datylon, they make a distinction between the easily-confused "icon array chart" and the "waffle chart." DataViz Project calls is a "pictorial unit chart" and takes the concept further with the "pictorial fraction chart" and the "pictorial percentage chart," both of which use pictograms to show fractions.
The “Nighingale chart” (named after Florence Nightingale) is included in all the libraries, but the DataViz Project prefers to call it a”polar area chart,” leaving out the term “Nightingale” altogether.
The “quadrant chart” of Chartopedia and Datylon is absent from the Data Visualisation Catalogue and shows up on DataViz Project as a “SWOT analysis”.
DataViz Project takes a “chord diagram” one step further with its “non-ribbon chord diagram.” Also here you’ll find a “triangle bar chart” and a “curved bar chart,” neither of which is found in the other libraries.
What charts do they all agree on as far as name and inclusion? The ubiquitous bar chart and pie chart as well as the choropleth map and heatmap are mainstays (though one site lists "heatmap" as two words).
After reviewing these libraries, I will never again get a “population pyramid” confused with a “pyramid chart.”
Below is a comparison table of the libraries (and one poster):
CHART LIBRARY | NUMBER OF DIFFERENT CHART TYPES | NUMBER OF CATEGORIES FOR THE CHARTS |
Data Visualization Catalogue | 60 (plus more on their blog) | 16 |
DataViz Project | 160 | 7 |
Datylon | 80 | 6 |
Visual Vocabulary poster | 74 | 9 |
Chartopedia | 70 | 8 |
It's worth mentioning that the chart-generating browser tool RAWGraphs also has an informative chart library, but you must first paste in your data to access it. Each chart comes with a how-to tutorial video. The videos can be accessed directly on the RAWGraphs Resources page.
After you have studied the sites above, it's time to find actual examples of the charts. lf I were a teacher of data visualization, one book I would make mandatory for study is the phenomenal The Infographic History of the World by Valentina D'Efilippo & James Ball (2016). Each page is a stunning example of practically every type of chart in the libraries above. It's a fun exercise to go page-by-age and try to identify the chart type they used. Because they are so cleverly designed, I found it to be harder than it looks! The designers push the boundaries of these charts and the entire book is a delight.
Studying the visualizations in this book can really sharpen your chart-naming skills as it show how the same chart can be creatively used in many different ways, but still retain its core properties. Like the part-to-whole icon chart below of "Her Majesty's Armed Forces", arranged as a silhouette of... her majesty.
Have fun with these sites and remember to check them often as they are always adding new types of charts!