Neato

Neato is a graph layout program within the Graphviz suite that focuses on arranging undirected graphs. It uses a spring-electrical (force-directed) model to position nodes by simulating repulsive forces between node pairs and attractive forces along edges. Through iterative adjustment, neato seeks layouts that distribute nodes evenly while reflecting the graph’s connectivity, producing aesthetically balanced drawings for moderate-sized graphs.

In neato, edge lengths can be influenced by edge attributes or weights, allowing users to encourage shorter or longer connections between certain node pairs. The algorithm tends to produce readable layouts by smoothing node placement and spacing, though it does not guarantee planarity. Neato supports constraints such as fixed node positions or specified edge length hints to guide the layout process.

Input to neato is typically a graph described in the DOT language. It can handle various graph attributes for nodes and edges, including shapes, sizes, colors, and weights. Neato can output layout data in multiple formats via Graphviz’s output options, including vector formats like SVG and PostScript and raster formats like PNG, depending on the chosen target format. Common usage involves piping a DOT file through the neato command with a -T option to select the output format, for example neato -Tsvg input.dot -o output.svg.

Neato is one of several Graphviz layout engines; it is particularly suitable for undirected graphs where a force-directed arrangement is desirable. For very large graphs, Graphviz provides alternative engines such as sfdp. Neato has been part of Graphviz since its early releases and remains a standard tool within the package.