dot
hierarchical or layered drawings of directed graphs.
Layout Engines
Various algorithms for projecting abstract graphs into a space for visualization.
neato
spring model layouts.
fdp
stands for Force-Directed Placement.
sfdp
stands for Scalable Force-Directed Placement.
twopi
radial layout.
nop
Pretty-print DOT graph file. Equivalent to nop1.
nop2
Pretty-print DOT graph file, assuming positions already known.
osage
draws clustered graphs.
patchwork
draws map of clustered graph using a squarified treemap layout.
Writing Layout Plugins
How to write a custom layout engine.