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<span id="openzim-page-title" class="mw-page-title-main"><span class="mw-page-title-main">Graph Modelling Language</span></span>
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</style><div role="note" class="hatnote navigation-not-searchable">Not to be confused with <a href="GraphML" title="GraphML">GraphML</a>.</div>
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</style><table class="infobox"><tbody><tr><th scope="row" class="infobox-label" style="line-height: 1.2; padding-right: 0.65em;"><a href="Filename_extension" title="Filename extension">Filename extension</a></th><td class="infobox-data" style="line-height: 1.35;"><style data-mw-deduplicate="TemplateStyles:r886049734">
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.gml</div></td></tr><tr><th scope="row" class="infobox-label" style="line-height: 1.2; padding-right: 0.65em;"><a href="Media_type" title="Media type">Internet media type</a></th><td class="infobox-data" style="line-height: 1.35;"><div class="monospaced">
text/vnd.gml</div></td></tr><tr><th scope="row" class="infobox-label" style="line-height: 1.2; padding-right: 0.65em;">Developed by</th><td class="infobox-data" style="line-height: 1.35;">Michael Himsolt</td></tr></tbody></table>
<p><b>Graph Modeling Language</b> (GML) is a hierarchical <a href="ASCII" title="ASCII">ASCII</a>-based file format for describing <a href="Graph_(discrete_mathematics)" title="Graph (discrete mathematics)">graphs</a>. It has been also named <i>Graph Meta Language</i>.
</p>
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<div class="mw-heading mw-heading2"><h2 id="Example">Example</h2></div>
<p>A simple graph in GML format:
</p>
<pre>graph [
comment "This is a sample graph"
directed 1
id 42
label "Hello, I am a graph"
node [
id 1
label "node 1"
thisIsASampleAttribute 42
]
node [
id 2
label "node 2"
thisIsASampleAttribute 43
]
node [
id 3
label "node 3"
thisIsASampleAttribute 44
]
edge [
source 1
target 2
label "Edge from node 1 to node 2"
]
edge [
source 2
target 3
label "Edge from node 2 to node 3"
]
edge [
source 3
target 1
label "Edge from node 3 to node 1"
]
]
</pre>
<div class="mw-heading mw-heading2"><h2 id="Applications_supporting_GML">Applications supporting GML</h2></div>
<ul><li><a href="Cytoscape" title="Cytoscape">Cytoscape</a>, an <a href="Open-source_license" title="Open-source license">open source</a> <a href="List_of_bioinformatics_software" title="List of bioinformatics software">bioinformatics software</a> platform for visualizing molecular interaction networks, loads and save previously-constructed interaction networks in GML.</li>
<li><a href="Igraph" title="Igraph">igraph</a>, an <a href="Open-source_license" title="Open-source license">open source</a> network analysis library with interfaces to multiple programming languages.</li>
<li><a href="Gephi" title="Gephi">Gephi</a>, an <a href="Open-source_license" title="Open-source license">open source</a> graph visualization and manipulation software.</li>
<li><a href="Graph-tool" title="Graph-tool">Graph-tool</a>, a <a href="Free_software" title="Free software">free</a> Python module for manipulation and statistical analysis of graphs.</li>
<li><a href="NetworkX" title="NetworkX">NetworkX</a>, an <a href="Open-source_license" title="Open-source license">open source</a> <a href="Python_(programming_language)" title="Python (programming language)">Python</a> library for studying complex graphs.</li>
<li><a href="Tulip_(software)" title="Tulip (software)">Tulip (software)</a> is a free software in the domain of <a href="Information_visualisation" class="mw-redirect" title="Information visualisation">information visualisation</a> capable of manipulating huge graphs (with more than 1.000.000 elements).</li>
<li><a href="YEd" title="YEd">yEd</a>, a free Java-based graph editor, supports import from and export to GML.</li>
<li>The <a href="Graphviz" title="Graphviz">Graphviz</a> project includes two command-line tools (gml2gv and gv2gml) that can convert to and from the <a href="DOT_(graph_description_language)" title="DOT (graph description language)">DOT</a> file format.</li>
<li><a href="Wolfram_Language" title="Wolfram Language">Wolfram Language</a>, a general very high-level programming language, supports <a rel="nofollow" class="external text" href="https://reference.wolfram.com/language/ref/format/Graphlet.html">GML import and export</a>.</li></ul>
<div class="mw-heading mw-heading2"><h2 id="See_also">See also</h2></div>
<ul><li><a href="Graph_Query_Language" title="Graph Query Language">Graph Query Language</a> (GQL)</li>
<li><a href="DGML" title="DGML">DGML</a></li></ul>
<div class="mw-heading mw-heading2"><h2 id="References">References</h2></div>
<p><sup id="cite_ref-1" class="reference"><a href="#cite_note-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup>
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<li id="cite_note-1"><span class="mw-cite-backlink"><b><a href="#cite_ref-1">^</a></b></span> <span class="reference-text">
Plenz, M., Frank, A., Graph Language Models, 2401.07105, cs.CL, 2024, <a rel="nofollow" class="external free" href="https://arxiv.org/abs/2401.07105">https://arxiv.org/abs/2401.07105</a>, access date: 2025-07-03</span>
</li>
</ol></div></div>
<div class="mw-heading mw-heading2"><h2 id="External_links">External links</h2></div>
<ul><li><a rel="nofollow" class="external text" href="https://web.archive.org/web/20190303094704/http://www.fim.uni-passau.de:80/fileadmin/files/lehrstuhl/brandenburg/projekte/gml/gml-technical-report.pdf">GML: A portable Graph File Format</a>, Michael Himsolt - 2010/11/30 (<a rel="nofollow" class="external text" href="https://web.archive.org/web/20190303094704/http://www.fim.uni-passau.de:80/fileadmin/files/lehrstuhl/brandenburg/projekte/gml/gml-technical-report.pdf">archived version</a>)</li>
<li>Unravelling Graph-Exchange File Formats, by Matthew Roughan and Jonathan Tuke, 2015, <a rel="nofollow" class="external free" href="https://arxiv.org/pdf/1503.02781.pdf">https://arxiv.org/pdf/1503.02781.pdf</a></li></ul>
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</style><div id="Graph_representations87" style="font-size:114%;margin:0 4em">Graph representations</div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%">Data structures</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em">
<ul><li><a href="Graph_(abstract_data_type)" title="Graph (abstract data type)">Graph (abstract data type)</a></li>
<li><a href="Adjacency_list" title="Adjacency list">Adjacency list</a></li>
<li><a href="Edge_list" title="Edge list">Edge list</a></li>
<li><a href="Adjacency_matrix" title="Adjacency matrix">Adjacency matrix</a></li>
<li><a href="Incidence_matrix" title="Incidence matrix">Incidence matrix</a></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">XML-based formats</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em">
<ul><li><a href="DGML" title="DGML">DGML</a></li>
<li>DotML</li>
<li>GEXF</li>
<li><a href="GraphML" title="GraphML">GraphML</a></li>
<li><a href="GXL" title="GXL">GXL</a></li>
<li><a href="XGMML" title="XGMML">XGMML</a></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Text-based formats</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em">
<ul><li><a href="DOT_(graph_description_language)" title="DOT (graph description language)">DOT</a></li>
<li> (GML)</li>
<li><a href="LCF_notation" title="LCF notation">LCF notation</a> for cubic Hamiltonian graphs</li>
<li><a href="Newick_format" title="Newick format">Newick format</a> for trees</li>
<li><a href="Trivial_Graph_Format" title="Trivial Graph Format">Trivial Graph Format</a></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Related concepts</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em">
<ul><li><a href="Graph_database" title="Graph database">Graph database</a></li>
<li><a href="Graph_drawing" title="Graph drawing">Graph drawing</a></li>
<li><a href="Linked_data" title="Linked data">Linked data</a></li></ul>
</div></td></tr></tbody></table></div>
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