D3 Git History Streamgraph
This streamgraph visualizes commit activity across D3’s GitHub repositories over time, with each layer representing a repository and its thickness reflecting smoothed weekly commit counts. The layer order follows each repository’s first commit, revealing the shift from the monolithic d3 repo to a package explosion during the 4.0 release. Using d3.stack with stackOffsetWiggle and stackOrderAppearance, the code applies array-blur smoothing to the data, renders SVG paths via d3.area, and adds hover effects that highlight individual layers. The visualization links each layer to its repository, and labels are positioned using d3-area-label. Data comes from a JSON file of all D3 commits.
AI-generated descriptionThis is an experiment in visualizing D3 Git History. Each layer is a D3 repository. The thickness of each layer is the number of commits per week with smoothing applied. This visualization uses a modified Streamgraph technique where the layer order is determined by the time of the first commit. So, as you read the labels from bottom to top, that corresponds to the history of when each repository was introduced.
On the whole, one can see that development occurred in the original monolithic d3 repository from late 2010 to mid 2014. In late 2014 we see an explosion of packages, corresponding to the 4.0 release of D3. Since that great explosion, we see a big push on d3-delaunay in 2018, and ongoing development/maintenance work pretty evenly distributed across the various D3 packages.
This piece was created as a submission for D3 Parade 2021.
It was the starting point for the open source project: stamen/git-history-streamgraph.