VISUALIZE MULTIPLE DATASETS
AND COMPARE TRENDS
WITH HORIZON GRAPHS
Click on the image to see a full screen display of over 30 time series datasets on a single screen with this Horizon Graph.
See huge amounts of information
in a single screen
Horizon Graphs are a fantastic way to overview a large number of time series in a limited rectangular space. Since this information visualization packs the information in a line graph in 1/6th the space through a smart pre-attentive color encoding, it allows for an overview of a large number of time series. Users can scan huge amounts of data points across all relevant time series and immediately identify areas of concern that require closer scrutiny.
Learn how to interpret Horizon Graphs with this video
We developed the Horizon Graph to make it easy to examine how a large number of items (stocks, product sales, employee satisfaction, and other data) have changed through time. Horizon Graphs let you:
Spot extraordinary behaviors and predominant patterns
View each item independently from the others
Make comparisons between items
View changes with enough precision to determine if further examination is required
Jeffrey Heer at Stanford University together with Nicholas Kong and Maneesh Agrawala at the University of California at Berkeley published a research study that compares the performance of the Horizon Graph to that of a line graph. The study is entitled "Sizing the Horizon: The Effects of Chart Size and Layering on the Graphical Perception of Time Series Visualizations". In brief, they come to the conclusion that the Horizon Graph is more effective than the traditional line graph when graph sizes are small. The Horizon Graph results in fewer estimation errors, with similar or slightly longer estimation times. Read this research paper.
See and compare trends in complex datasets
This data visualization displays quantitative values using a combination of length (like in a line graph, where the height of the curve represents the underlying value) and color. Users can read exact values from the visualization by hovering their cursor over specific points on the Graph.
Start with a standard line graph.
Color code the graph — red indicates negative values and blue indicates positive values. Shades of red and blue indicate value ranges.
Invert the negative values so that the entire graph is above the "zero" line.
Collapse the graph on itself so that all values appear in a constrained vertical space.
Our Horizon Graph visualization is particularly useful when you need to see a large number of time series on a single screen. This makes it easy to compare trends and spot patterns that would be very difficult or impossible to see in a standard report. They work well with Treemap, Heatmap, Heat Matrix, Barseries and Stack Graph visualizations since they allow you to see your data from different perspectives.
Information Visualization guru Stephen Few wrote about Horizon Graphs in his influential Perceptual Edge blog. He said:
"Almost every good invention is developed in response to a particular problem. The Horizon Graph was
developed in response to a need shared by many organizations to examine how a large number of items
(stocks, product sales, employee satisfaction, and so on) changed through time... The Horizon Graph succeeds because its
designer kept the rules of visual perception in mind as he worked his way, one design step at
a time, testing each as he proceeded, towards the goal. This is a good example of how effective innovations in
the field of information visualization are developed.
"
"The information visualization research community produces many innovations each year, which I’m always
excited to discover in the research literature or during visits to research labs. I get a special thrill, however,
when I find an effective innovation that has been incorporated into commercial software, where it must reside
to reach a broad audience. Only a few commercial software vendors are producing effective visualization
solutions today. When I run across an example like the Horizon Graph, it gives me joy to make it known and
praise its worth. It gives me greater joy by far than what I get when bemoaning the poor designs of most
business intelligence vendors, which is rarely fun at all."
