Friday, January 12, 2018

Friday Fun LVII - Stream Charts


Here we go again...last week I stumbled upon a really nice charts that are inspired by Edward Tufte's Stream Charts. This is how they look like...

And here you can find more information about them.
The chart can be used to visualize a series of data with the variation of the data it contains over time. On each date different items of the series are stacked like in a stacked bar chart. The items are sorted by their value from bottom to top, meaning to say the items with the lowest value are always at the bottom and the one with the highest values are always on top.
To be honest I have again no use case for it but I really like the visualization. By choosing the colors wisely one could visualize dominating series over time very well.
Long story is my implementation of such a chart...

As you can see I don't have such good data as in the example above but you get the idea :)

To create such a chart I make use of my ChartItem class which has a timestamp property that is needed here to group the chart items for the visualization. The idea is to have a list of ChartItems that may also contain multiple ChartItems from the same day. The StreamChart component has a category property which can be one of the following categories:

  • DAY
  • WEEK
  • YEAR

So let's assume you have a list of ChartItems that contains data from different days and you would like to visualize the chart grouped by days you set the category to DAY.
With this feature you can define if you would like to group the given list of ChartItems by one of the above categories...hmm...hope that explanation was more or less clear :)

It might be easier to simply take a look at the source code (see links below).

In principle this chart is similar to the Sankey Plot but not exactly the same so I've started from there and created a modified version which you can see above. This chart is now part of my own JavaFX charts library which you can find here:

sources at github

binaries at bintray

Please find the demo classes for all the charts in the test package.

Well that's it for keep coding...

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