From EduTech Wiki
Jump to: navigation, search

This article or section is a stub. A stub is an entry that did not yet receive substantial attention from editors, and as such does not yet contain enough information to be considered a real article. In other words, it is a short or insufficient piece of information and requires additions.


1 Definition

  • Graphviz is an open source graph visualization software. It has several main graph layout programs, called layout engines.
hierarchical drawings of directed graphs. The layout algorithm aims edges in the same direction (top to bottom, or left to right) and then attempts to avoid edge crossings and reduce edge length.
spring model - attempts to minimize a global energy function, which is equivalent to statistical multi-dimensional scaling. See also fdp.
spring model layouts similar to those of neato, but does this by reducing forces rather than working with energy.
multiscale version of fdp for the layout of large graphs.
radial layouts, The nodes are placed on concentric circles depending their distance from a given root node.
circular layout - suitable for certain diagrams of multiple cyclic structures such as certain telecommunications networks

2 The GraphViz language and command line syntax

2.1 Command line syntax

See Command-line Invocation (at

GraphViz includes several command line commands. The most imporant one is dot

The syntax pattern is:

cmd [ flags ] [ input files ]


dot -Tsvg > GCF2.svg

Important flags:

Defines the output format. You also can choose from a renderer and change the default formatter for the renderer.
See the list of output formats.
Most important ones for web pages: png, svg, cmapx (client-side html map), imap (server-side html map) and vrml (partially supported)
Most important ones for printing: png, svg, ps, pdf
Most important ones for specialized clients: dot (reproduces the input, along with layout information for the graph), xdot (same with lots of additional information)


dot -Kneato is equivalent to running neato
dot -Ktwopi runs the radial twopi engine
Defines attributes of the graph like overlaps, fonts, etc.
specify the output file. Otherwise it's written to default output.

2.2 Format, rendering engines, formatters and layout engines

Here are some examples

Client-side HTML maps
creates client-side image maps (of course you'll have to attache URLS to either nodes or edges or both)


dot -Tcmapx -Tpng -oyour_graph.png

Then use something like:

<IMG SRC="your_graph.png" USEMAP="#mainmap" /> 
... [content of] ... 
SVG output using the default dot layout engine

Default use:

dot -Tsvg

Create SVG output using the cairo renderer and formatter

dot -Tsvg:cairo:cairo
SVG output with the twopi engine
dot -Ktwopi -Tsvg > GCF2.svg
PDF output with the twopi or fdp layout engines
dot -Ktwopi -Tpdf > GCF2.pdf
dot -Kfdp -Tpdf > GCF2.pdf
PNG output

Default use:

dot -Tpng 

specifies PNG output produced by Cairo formatted using the GD library:

dot  -Tpng:cairo:gd
xdot output
Pratical to see where nodes are being positioned so that you can manually change things
Also useful with graphviz clients


dot -Ksfdp -Txdot > temp.xdot

2.3 Some Neato command line examples

Lists configuration

neato -v

List all formats your installation can produce

neato -Tformat:

PNG output without overlap

neato -Tpng -Goverlap=false > GCF.png

SVG output

neato -Tsvg > GCF.svg
neato -Tsvg -Goverlap=scale -Gfontsize=8.0 >

3 Graph files

3.1 Graph file syntax

Below is a semi-formal grammar (i.e. the real grammar simplified). See the official doc for a complete one.

Parentheses ( and ) indicate grouping when needed. Italic square brackets [ and ] enclose optional items. Vertical bars ¦ separate alternatives. Stuff in bold must be typed "as is", e.g. bold [ ... ] square brackets or graph

graph --> (digraph ¦ graph) id {statement-list}
statement-list --> statement; statement; ...
statement --> attr-statement ¦ node-statement ¦ edge-statement ¦ subgraph cluster_xxx {...}
node-statement --> id [ attr-list ]
attr-statement --> (graph ¦ node ¦ edge) [attr-list ]
id --> id = id
attr-list --> id=val_id, id=val_id, ....
id --> String ¦ quoted string
edge-statement --> id (-- ¦ ->) id [attr-list]

Are C++ style, i.e. either /* ....*/, // or #

Identifiers (id and val_id)
  • Must start with a letter
  • Unquoted strings only can contain [A-Z][a-z][0-9] and "_"
  • Otherwise strings must be quoted

3.2 Graphviz attributes

See either (or both):

In addition.

We we understood right (this is a disclaimer!)

  • You may set these (most?) as global settings in the command line
  • As global settings in a file at the graph level or for all nodes or for all edges.
  • As "parameter" for node statements
  • As "parameter" for edge statements

Also, some will not work with certain layout programs and there is interaction. I.e. sometimes it's quite difficult to figure out what given attributes will do. I found that pinning down nodes in given locations won't work with sfdp (or maybe I didn't figure out how to do this ...) - Daniel K. Schneider 13:46, 24 May 2010 (UTC).

defines the size of the output in inches
Consult Wikipedia's papersize or ISO 216 articles for pratical tables that translate ISO (European) A,B,C formats to inches.

Example of a portrait A2 page:

Is a crucial attribute for larger graphs that should fit on a given canevas size


will try to fill a "page" defined by its size.
Defines multiple page outputs (only works with PS)

Example of A3 output (biggest page a typical laser printer can handle)

Defines the shape of a none

Example of a node redition:

Remove shape (keep the text only), make it smaller:
node [fontsize=8,shape=none];
determines if and how node overlaps should be remove. There exist several alorithms



3.3 Edge and node attributes

Some attributes only apply to either nodes or edges


node [fontsize=14,fontname="Arial",shape=none,nodesep=1,ranksep=2];
edge [arrowhead=normal,arrowsize=0.3,len=0.3]

4 Simple graphviz for mediawiki examples

In this wiki, a directed graph that is represented like this (if you use the graphviz software as standalone program, you should remove the XML tags with are specific to the Graphviz mediawiki extension we are using here).

digraph G4 {
            node [fontsize="10"];
            "Learning Theory" [URL="Learning theory"];
            "Pedagogic strategy" [URL="Pedagogic strategy"];
	    "Instructional design model" [URL="Instructional design model"];
            "Learning Theory" -> "Pedagogic strategy";
            "Instructional design model" -> "Pedagogic strategy"

could render like that (yes this wiki has a graphviz extension, but we may not keep it for sure since it is somewhat CPU intensive)

Graph image creation requires permission to upload.

A simple non-directed graph (Notice: the XML attributes are ignored, worked once with an older version that is lost to humanity:

 graph G1 {
    aaa -- bbb;
    bbb -- c;
    aaa -- c;


Graph image creation requires permission to upload.

Or a more complex non-directed graph:

graph G7 {
   node [fontsize="8"];
   run -- intr;
   intr -- runbl;
   runbl -- run;
   run -- kernel;
   kernel -- zombie;
   kernel -- sleep;
   kernel -- runmem;
   sleep -- swap;
   swap -- runswap;
   runswap -- new;
   runswap -- runmem;
   new -- runmem;
   sleep -- runmem;

like this

Graph image creation requires permission to upload.

5 Tools

See Graphviz - Graph Visualization Software (a longer list of interfaces, bindings, generators, scripts, etc.). Usually also needs graphviz software and the other way round. I.e. after installing Graphviz, you likely want to install a viewer or generator.

5.1 Mediawiki extensions

5.2 GraphiViz Viewers

6 Installation

  • Download of GraphViz software (source and Win/Linux binaries).
  • The windows version has a *.msi installer. For VISTA, a command-line install is recommended, but I had to run the "click-on-it" install in order to have the gui tools through the command menu. Anyhow, it works fine both under VISTA and Win7
Ubuntu 64-bit 14 LTS
  • apt-get install graphviz
  • However, sfdp still doesn't work (this is true since Ubuntu 10, years ago ...)
Error: remove_overlap: Graphviz not built with triangulation library

... Manual installation/compilation could work, but I am too old for that and use my Windows PC instead ;)

Ubunto 64-bit server

Download (as of May 2010):



pkg -i libgraphviz4_2.26.3-1_amd64.deb 
dpkg -i graphviz_2.26.3-1_amd64.deb 

Since it is is likely that libraries are missing, type the following that should fix everything, i.e. retrieve missing stuff and install everything :)

apt-get -f install

Note: Again, you will have to do this manually since the graphviz in the official Ubuntu install is old (sfdp layout engine missing)

  • For solaris, you can download a binary from plus these (check the version dependencies): cairo-xxx, freetype-xxx, glib-xxx, graphviz-xxx, pango-xxx, xrender-xxx, expat-xxx.

7 Tutorials and introductions

  • Graphviz - Graph Visualization Software Includes both introductions and manuals. However, first contact with the documentation is confusing, i.e. finding the appropriate pages for a problem is not so easy. Also, there is no beginners tutorial that simply shows solutions for typical use cases.
Graphviz for UML