GraphML

{{Short description|File format for graphs}} {{Distinguish|Graph Modelling Language}} {{Infobox file format | name = GraphML | icon = | iconcaption = | icon_size = | screenshot = | screenshot_size = | caption = |_noextcode = | extension =  |_nomimecode = | mime = | type code = | uniform_type = | conforms_to = | magic = | developer = [http://graphdrawing.org/ Graph Drawing] | released =  | latest_release_version = | latest_release_date =  | genre = Graph description language | container_for = | contained_by = | extended_from = | extended_to = | standard =  | free = | url = {{URL|http://graphml.graphdrawing.org/}} }}

'''GraphML''' is an XML-based file format for graphs. The GraphML file format results from the joint effort of the graph drawing community to define a common format for exchanging graph structure data. It uses an XML-based syntax and supports the entire range of possible graph structure constellations including directed, undirected, mixed graphs, hypergraphs, and application-specific attributes.<ref>{{Cite book|contribution=Graph Markup Language (GraphML)|first1=Ulrik|last1=Brandes|author1-link=Ulrik Brandes|first2=Markus|last2=Eiglsperger|first3=Jürgen|last3=Lerner|first4=Christian|last4=Pich|url=https://cs.brown.edu/people/rtamassi/gdhandbook/chapters/graphml.pdf|pages=517–541|editor-first=Roberto|editor-last=Tamassia|editor-link=Roberto Tamassia|title=Handbook of Graph Drawing and Visualization|publisher=CRC Press}}.</ref>

==Overview== A GraphML file consists of an XML file containing a <code>graph</code> element, within which is an unordered sequence of <code>node</code> and <code>edge</code> elements. Each <code>node</code> element should have a distinct <code>id</code> attribute, and each <code>edge</code> element has <code>source</code> and <code>target</code> attributes that identify the endpoints of an edge by having the same value as the <code>id</code> attributes of those endpoints. Here is what a simple undirected graph with two nodes and one edge between them looks like: <syntaxhighlight lang="xml"> <?xml version="1.0" encoding="UTF-8"?> <graphml xmlns="http://graphml.graphdrawing.org/xmlns" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://graphml.graphdrawing.org/xmlns/1.0/graphml.xsd"> <graph id="G" edgedefault="undirected"> <node id="n0"/> <node id="n1"/> <edge id="e1" source="n0" target="n1"/> </graph> </graphml> </syntaxhighlight>

Additional features of the GraphML language allow its users to specify whether edges are directed or undirected, and to associate additional data with vertices or edges.

==See also== *yEd, a widespread graph editor that uses GraphML as its native file format (but ports, hypergraphs not supported and limited nested graphs support). *Gephi, a graph visualization software that supports a limited set of GraphML. *DOT (graph description language) *Boost libraries allow to read from and write to GraphML format.

==References== {{reflist}}

==External links== *{{Official}} *[http://graphml.graphdrawing.org/primer/graphml-primer.html GraphML Primer] *[https://web.archive.org/web/20190814062720/http://www.svgopen.org/2003/papers/ComparisonXML2SVGTransformationMechanisms/ Comparison between XML to SVG Transformation Mechanisms], showing conversions between GraphML and SVG

{{Graph representations}} Category:XML markup languages Category:Graph description languages Category:XML-based_standards