DataFormats»Graph ML

Graph ML

Seems like a bunch of projects use it, including JUNG

Main site:

http://graphml.graphdrawing.org/

Specification

http://graphml.graphdrawing.org/specification.html

Example Parsers

Java

from JUNG GraphML.java

C

from Pigale

Links / info

GraphML Extension Package (yWorks)

comments:

  • I would use two tags edge and arc instead of edge+directed/undirected. This is not serious comment because the description is intended to be used mainly by programs. But in general I find GraphML powerful enough to express all the data that I can express in Pajek's format.
  • XML allows (user's) format extensions.
  • GrapmML does not have the ability to express "this graph will have only [un]directed edges in it"; there's basically no good way (aside from reading through the entire file twice) to make sure taht a given graph is stricty directed or undirected. (You can specify a _default_ edge type, but that's not a constraint.)

Short Example:

<?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
    http://graphml.graphdrawing.org/xmlns/1.0/graphml.xsd">
 <graph id="G" edgedefault="undirected">
   <node id="n0"/>
   <node id="n1"/>
   <node id="n2"/>
   <node id="n3"/>
   <node id="n4"/>
   <node id="n5"/>
   <node id="n6"/>
   <node id="n7"/>
   <node id="n8"/>
   <node id="n9"/>
   <node id="n10"/>
   <edge source="n0" target="n2"/>
   <edge source="n1" target="n2"/>
   <edge source="n2" target="n3"/>
   <edge source="n3" target="n5"/>
   <edge source="n3" target="n4"/>
   <edge source="n4" target="n6"/>
   <edge source="n6" target="n5"/>
   <edge source="n5" target="n7"/>
   <edge source="n6" target="n8"/>
   <edge source="n8" target="n7"/>
   <edge source="n8" target="n9"/>
   <edge source="n8" target="n10"/>
 </graph>
</graphml>