View source for Streamgraph

{{Short description|Type of stacked area graph}}[[Image:LastGraph_example.svg|thumb|200px|A ThemeRiver of music listened to by a user|alt=]]
A '''streamgraph''', or '''stream graph''', is a type of stacked [[Area chart|area graph]] which is displaced around a [[Cartesian coordinate system|central axis]], resulting in a flowing, organic shape. Unlike a traditional stacked area graph in which the layers are stacked on top of an axis, in a streamgraph the layers are positioned to minimize their "wiggle". More formally, the layers are displaced to minimize the sum of the squared slopes of each layer, weighted by the area of the layer.<ref name=":0">{{cite journal|last1=Byron|first1=Lee|last2=Wattenberg|first2=Martin|date=November–December 2008|title=Stacked Graphs – Geometry & Aesthetics|journal=IEEE Transactions on Visualization and Computer Graphics|publisher=IEEE Computer Society|volume=14|issue=6|pages=1245–1252|doi=10.1109/TVCG.2008.166|issn=1077-2626|pmid=18988970|s2cid=15281429}}</ref> Streamgraphs display data with only positive values, and are not able to represent both negative and positive values.<ref name=":1">{{Cite journal|last1=Bartolomeo|first1=Marco Di|last2=Hu|first2=Yifan|date=2016|title=There is More to Streamgraphs than Movies: Better Aesthetics via Ordering and Lassoing|url=https://onlinelibrary.wiley.com/doi/abs/10.1111/cgf.12910|journal=Computer Graphics Forum|language=en|volume=35|issue=3|pages=341–350|doi=10.1111/cgf.12910|s2cid=17724977|issn=1467-8659}}</ref>

Streamgraphs and their use were popularized by [[Biography:Amanda Cox|Amanda Cox]] in a February 2008 ''{{wipe|New York Times}}'' article on movie [[Engineering:Box office|box office]] revenues.<ref>{{cite news |title=The Ebb and Flow of Movies: Box Office Receipts 1986–2007 |author=Matthew Bloch|author2=Lee Byron|author3=Shan Carter|author4=Amanda Cox |url=https://www.nytimes.com/interactive/2008/02/23/movies/20080223_REVENUE_GRAPHIC.html |newspaper=The New York Times |date=23 February 2008 |access-date=24 July 2012}}</ref> Cox got the idea from then-undergraduate Lee Byron,<ref name=":0" /> who had used a similar method for visualizing his music listening history.<ref>{{Cite news|date=2008-02-25|title=Talk to the Newsroom: Graphics Director Steve Duenes|language=en-US|work=The New York Times|url=https://www.nytimes.com/2008/02/25/business/media/25asktheeditors.html|access-date=2021-04-24|issn=0362-4331}}</ref>

A related graph, sometimes conflated with streamgraphs, is the ThemeRiver, in which the "silhouette" of the graph is symmetrically arranged around the central axis.<ref name=":0" />

Streamgraphs were found to be more readable than basic stacked area graphs or ThemeRivers for value comparison tasks.<ref>{{Cite journal|last1=Thudt|first1=Alice|last2=Walny|first2=Jagoda|last3=Perin|first3=Charles|last4=Rajabiyazdi|first4=Fateme|last5=MacDonald|first5=Lindsay|last6=Vardeleon|first6=Riane|last7=Greenberg|first7=Saul|last8=Carpendale|first8=Sheelagh|date=June 2016|title=Assessing the Readability of Stacked Graphs|url=https://dl.acm.org/doi/abs/10.5555/3076132.3076164|journal=Proceedings of the 42nd Graphics Interface Conference|series=GI '16|location=Victoria, British Columbia, Canada|publisher=Canadian Human-Computer Communications Society|pages=167–174|isbn=978-0-9947868-1-4}}</ref>

Streamgraphs are officially supported by [[Software:Matplotlib|Matplotlib]]<ref>{{Cite web|title=matplotlib.axes.Axes.stackplot — Matplotlib 3.1.2 documentation|url=https://matplotlib.org/3.1.1/api/_as_gen/matplotlib.axes.Axes.stackplot.html|access-date=2020-10-06|website=matplotlib.org}}</ref> and [[Software:D3.js|D3.js]].<ref>{{Cite web|title=d3/d3-shape|url=https://github.com/d3/d3-shape|access-date=2020-10-06|website=GitHub|language=en}}</ref>

Marco Di Bartolomeo and Yifan Hu (2016) propose several improvements to streamgraphs, such as using 1-norm minimization instead of 2-norm minimization.<ref name=":1" />

==References==
<references />

==External links==
* [https://github.com/leebyron/streamgraph_generator Lee Byron's streamgraph_generator]
* [http://app.rawgraphs.io/ RAWGraphs] Open-source visualization tool easing streamgraph generation.
* [https://wiretrip.github.io/streamgraph-post/ StreamGraph] Open-source javascript for generating a streamgraph in SVG.

[[Category:Diagrams]]
[[Category:Statistical charts and diagrams]]



{{Sourceattribution|Streamgraph}}