About.ht

<p>&nbsp;</p>

<h2>Graph Visualization</h2>

<p>Graph visualization is a way of representing structural information as diagrams of abstract graphs and networks. It has important applications in networking, bioinformatics, &nbsp;software engineering, database and web design, machine learning, and in visual interfaces for other technical domains.</p>

<p>Graphviz is open source graph visualization software. It has several main layout programs. See the <a href="Gallery.php">gallery</a> for sample layouts. It also has web and interactive graphical interfaces, and auxiliary tools, libraries, and language bindings. We&#39;re not able to put a lot of work into GUI editors but there are quite a few&nbsp;external projects and even commercial tools that incorporate Graphviz. You can find some of these in the Resources section.</p>

<p>The Graphviz layout programs take descriptions of graphs in a simple text language, and make diagrams in useful formats, such as images and SVG for web pages; PDF or Postscript for inclusion in other documents; or display in an interactive graph browser.</p>

<p>Graphviz has many useful features for concrete diagrams, such as options for colors, fonts, tabular node layouts, line styles, hyperlinks, and custom shapes.</p>

<p>In practice, graphs are usually generated from an external data sources, but they can also be created and edited manually, either as raw text files or within a graphical editor. (Graphviz was not intended to be a Visio replacement, so it is probably frustrating to try to use it that way.) <!--
<h2>The Dynagraph saga</h2>
Graphviz is actively maintained and improved, but from 1996-2003
the Graphviz team (particularly Gordon Woodhull) also worked on
Dynagraph, a potential successor. It appears to be our own classic
case of ``second system'' syndrome.  Dynagraph shares almost
no code with Graphviz. It is based on a heavily templated
C++ graph library that's similar to the Boost Graph Library in some ways,
but follows Graphviz' graph data structure model.  Dynagraph
provides dynamic layout of on-line diagrams, with semi-interative editing.
It has a very powerful graphical interface layer for Microsoft
ActiveX, Motage, so ``live'' diagrams may be embedded
in Office documents, and may contain ActiveX controls. It does this
with full toolbar management and file persistence.  Dynagraph
also has a text API and a compatible Java front end that is 
Working Dynagraph code is included in the Graphviz source code release.
The ambition of this undertaking, and the sheer effort needed
to keep Montage working with all the different versions of
Windows and Office programs, has brought us to the point that
we need to change directions and find a new strategy for this work.
--></p>

<p>&nbsp;</p>

<h2>Roadmap</h2>
<!-- <a href="/cgi-bin/man?dot">dot</a> -->

<p><strong>dot</strong> - ``hierarchical&#39;&#39; or layered drawings of directed graphs. This is the default tool to use if edges have directionality. dot aims edges in the same direction (top to bottom, or left to right) and then attempts to avoid edge crossings and reduce edge length.</p>

<p><a href="Gallery/directed/cluster.html"><img alt="" src="Gallery/directed/cluster.small.png" style="display:block; margin-left:auto; margin-right:auto; margin-top:15px" /> </a></p>

<p><strong>neato</strong> - ``spring model&#39;&#39; layouts. &nbsp;This is the default tool to use if the graph is not too large (about 100 nodes) and you don&#39;t know anything else about it.&nbsp;Neato attempts to minimize a global energy function, which is equivalent to statistical multi-dimensional scaling. The solution is achieved using stress majorization, though the older Kamada-Kawai algorithm, using steepest descent, is also available. fdp implements the Fruchterman-Reingold heuristic including a multigrid solver that handles larger graphs and clustered undirected graphs.</p>

<div><a href="Gallery/undirected/ER.html"><img alt="" src="Gallery/undirected/ER.small.png" style="display:block; margin-left:auto; margin-right:auto; margin-top:15px" /> </a></div>

<p><strong>fdp</strong> - ``spring model&#39;&#39; layouts similar to those of neato, but does this by reducing forces rather than working with energy. Fdp implements the Fruchterman-Reingold heuristic including a multigrid solver that handles larger graphs and clustered undirected graphs.<a href="Gallery/undirected/fdpclust.html"><img alt="" src="Gallery/undirected/fdpclust.small.png" style="display:block; margin-left:auto; margin-right:auto; margin-top:15px" /> </a></p>

<p><strong>sfdp</strong> - multiscale version of fdp for the layout of large graphs.<img alt="" src="Gallery/undirected/200910_viz_matrix_188w.png" style="display:block; margin-left:auto; margin-right:auto; margin-top:15px" /></p>

<p><strong>twopi</strong> - radial layouts, after Graham Wills 97. Nodes are placed on concentric circles depending their distance from a given root node. You can set the root node, or let twopi do it.<a href="Gallery/twopi/twopi2.html"><img alt="" src="Gallery/twopi/twopi2.small.png" style="display:block; margin-left:auto; margin-right:auto; margin-top:15px" /> </a></p>

<p><strong>circo</strong> - circular layout, after Six and Tollis 99, Kauffman and Wiese 02. This is suitable for certain diagrams of multiple cyclic structures, such as certain telecommunications networks.<img alt="" src="Gallery/undirected/honda-tokoro.circo.png" style="display:block; margin-left:auto; margin-right:auto; margin-top:15px" /></p>

<h2>Viewers</h2>

<ul>
<li><a href="http://www.graphviz.org/cgi-bin/man?dotty">dotty</a> - a vintage customizable Unix/X windows viewer that has subsequently been ported to Microsoft Windows.</li>
<li><a href="http://www.graphviz.org/cgi-bin/man?tcldot">tcldot</a> - a TCL/TK scripting language extension for Graphviz</li>
<li><a href="http://api.graphviz.org/webdot/index.html">WebDot</a> - a tcldot scripted WWW service for graphs in HTML documents.
<p>There is also <a href="/Misc/webdot.pl">a simplified version</a> written in perl.</p>
</li>
<li><a href="http://www.research.att.com/~john/Grappa/">Grappa</a> - a Java package for graphs with full Java graph data structures</li>
<li><a href="http://zvtm.sourceforge.net/zgrviewer.html">ZGRViewer</a> - an SVG-based zooming graph viewer for large graphs.</li>
<li><a href="http://www.pixelglow.com/graphviz/">Mac OS X graphviz</a></li>
<li>smyrna - a prototype OpenGL viewer</li>
</ul>

<h2>Filters</h2>

<ul>
<li>gvpr is a general purpose graph stream editor, in the spirit of awk, sed (or think of perl if you don&#39;t know those).</li>
</ul>
<!--
<h2>Generators</h2>
Many external projects provide filters that translate other formats
and database into Graphviz format.
See <A HREF="Resources.php#generators-and-translators>this list</A>.

<h2>Libraries</h2>
Full disclosure requires us to explain that despite considerable interest
from outsiders, the Graphviz library APIs were really only intended to be
used by the Graphviz insiders.  For graph algorithm libraries you are
probably better off looking at LEDA, the Boost Graph Library, or similar packages.
<ul>
<li>
libgraph/libagraph
These are basic graph data structure libraries in C, layered on top of Vo's
cdt (C Dictionary Types).  The two libraries differ a little in how they handle
subgraphs and runtime attributes.  We hope to unify them eventually.
<li>
pathplan
This is a generic library for drawing arcs around obstacles diagrams.  
To us it's pretty spiffy, but it hasn't seen much outside interest.
</ul>

<p>Graphviz provides a collection of tools for manipulating graph structures and generating graph layouts.
-->

<h2>Example applications</h2>

<ul>
<li>Software documentation: <a href="http://www.graphviz.org/pub/graphviz/development/doxygen/html/structAgedge__t.html">Pretty diagrams</a> automatically generated by <a href="http://www.stack.nl/%7Edimitri/doxygen/index.html">doxygen</a> and <a href="/cgi-bin/man?dot">dot</a>. (From <a href="http://www.graphviz.org/pub/graphviz/development/doxygen/html/index.html">Graphviz source documentation</a>.)</li>
<li>WWW Graph Server: For a WWW application of Graphviz, please see <a href="http://www.graphviz.org/webdot/">Webdot</a>.</li>
<li><a href="http://code.google.com/apis/chart/docs/gallery/graphviz.html">Google Charts Graphviz API</a>. Hands across the water!&nbsp;</li>
<li><a href="http://code.google.com/p/canviz/">Canviz</a>, an HTML5 canvas Javascript library.</li>
</ul>
<!--
<h2>What tools does it provide?</h2>
<h3>Programs</h3>
<dl>
<dt><a href="http://www.graphviz.org/cgi-bin/man?dot">dot</a></dt>
<dd>A batch layout tool for directed graph layouts.  
The Input is a description of the graph in the <b>dot</b> language and
the output is a rendering of the graph in a choice of vector or bitmap
graphics formats. (The source can be either a "graph" or a "digraph")</dd>

<dt><a href="http://www.graphviz.org/cgi-bin/man?neato">neato</a></dt>
<dd>A batch layout tool for undirected graph layouts - spring model.  
The Input is a description of the graph in the <b>dot</b> language and
the output is a rendering of the graph in a choice of vector or bitmap
graphics formats. (The source can be either a "graph" or a "digraph")</dd>

<dt><a href="http://www.graphviz.org/cgi-bin/man?twopi">twopi</a></dt>
<dd>A batch layout tool for undirected graph layouts - circular.  
The Input is a description of the graph in the <b>dot</b> language and
the output is a rendering of the graph in a choice of vector or bitmap
graphics formats. (The source can be either a "graph" or a "digraph")</dd>

<dt><a href="http://www.graphviz.org/cgi-bin/man?circo">circo</a></dt>
<dd>A batch layout tool for undirected graph layouts - circular.  
The Input is a description of the graph in the <b>dot</b> language and
the output is a rendering of the graph in a choice of vector or bitmap
graphics formats. (The source can be either a "graph" or a "digraph")</dd>

<dt><a href="http://www.graphviz.org/cgi-bin/man?lefty">lefty</a></dt>
<dd>A  two-view  graphics editor for technical pictures.</dd>

<dt><a href="http://www.graphviz.org/cgi-bin/man?dotty">dotty</a></dt>
<dd>A lefty script for directed graphs</dd>

<dt><a href="http://www.graphviz.org/cgi-bin/man?lneato">lneato</a></dt>
<dd>A lefty script for undirected graphs.</dd>
</dl>

<h3>Tcl Extensions</h3>
<dl>
<dt><a href="http://www.graphviz.org/cgi-bin/man?tcldot">tcldot</a></dt>
<dd>The batch layout capabilities of <b>dot</b> and <b>neato</b>
accessible from Tcl.</dd>

<dt><a href="http://www.graphviz.org/cgi-bin/man?gdtclft">gdtclft</a></dt>
<dd>Tcl functions for drawing to bitmaps in various formats (png, jpeg, ...) 
using Tom Boutell's <a href="http://www.boutell.com/gd/"><b>gd</b></a>
and TrueType font rendering from
<a href="http://www.freetype.org/">FreeType</a>.
This code is used by the renderers in Tcldot, but the package
can also be used independently.</dd>

<dt><a href="http://www.graphviz.org/cgi-bin/man?tkspline">tkspline</a></dt>
<dd>A small extension to add bezier-spline smoothing methods to Tk.
Supports the edge routing algorithms used by Tcldot.</dd>

<dt><a href="http://www.graphviz.org/cgi-bin/man?tcldgr">tcldgr</a></dt>
<dd>Functions for the incremental manipulation of graph data structures.</dd>

<dt><a href="http://www.graphviz.org/cgi-bin/man?tcldgl">tcldgl</a></dt>
<dd>Incremental Layout engines for graphs.
Designed for use with Tcldgr, but can also be used independantly.</dd>

<dt>tclpathplan</dt>
<dd>Functions for computing shortest paths around polygon obstacles.</dd>
</dl>

<h3>Tcl Demonstration Scripts</h3>
<p>
(From the RPM these are normally installed in: /usr/share/graphviz/demo )
</p><p></p>
<dl>
<dt><a href="http://www.graphviz.org/doted_demo.gif">doted</a></dt>
<dd>A graph editor demonstrating the facilities of <b>tcldot</b>. 
Use the mouse to enter nodes and edges, then click on the
green button to layout the graph.</dd>

<dt><a href="http://www.graphviz.org/dge_demo.gif">dge</a></dt>
<dd>A dynamic graph editor demonstrating the facilities of
<b>tcldgr</b> and <b>tcldgl</b>.
Use the mouse to enter nodes and edges and the layout happens automatically
as you work.</dd>

<dt><a href="http://www.graphviz.org/entities_demo.png">entities</a></dt>
<dd>A demonstration of the TrueType font capabilities of <b>gdtclft</b>.</dd>

<dt><a href="http://www.graphviz.org/ihi_demo.gif">ihi</a></dt>
<dd>An implementation of the algorithm for Inferring Inheritance Heirarchies
by Ivan Moore and Tim Clement.  This is intended as a demonstration of the
usability of <b>tcldgr</b> without a layout engine (although the demo does still
use dot to visualize the result of the algorithm.)</dd>

<dt><a href="http://www.graphviz.org/pathplan_demo.gif">pathplan</a></dt>
<dd>A development tool that we used during the development of pathplan.
Uses <b>tclpathplan</b> to provide an editor in which you can
draw polygon obstacles and then request the shortest
bezier path between any two points.</dd>

<dt><a href="http://www.graphviz.org/spline_demo.gif">spline</a></dt>
<dd>A simple demonstration of the additional smoothing method
provided by <b>tkspline</b>.</dd>
</dl>
-->

<h3>Contacts</h3>

<p>If you have a bug or believe something is not working as expected, please submit a bug report using the <a href="http://www.graphviz.org/bugs/bugform.html">form</a>.<br />
If you have a general question or are unsure how things work, please consider posting first to the Graphviz <a href="http://www.graphviz.org/MailingList.php">mailing list</a>. We follow the list, but there are also many users who might be able to respond to you better or faster than we can. Please do not send detailed bug reports there.</p>

<p><a href="mailto:ellson@graphviz.org">John Ellson</a> (for problems with builds, installation, software configuration or this web server)</p>

<p><a href="mailto:erg@graphviz.org">Emden Gansner</a> (for all graph layout issues)</p>

<p><a href="mailto:yifanhu@research.att.com">Yifan Hu</a> (to contribute example graphs)</p>

<p><a href="mailto:arif@research.att.com">Arif Bilgin</a> (for Windows-related issues)</p>


<p><a href="mailto:dperry@research.att.com">Dwight Perry</a> (for website issues)</p>