Layouts

Wiki ▸ API Reference ▸ Layouts

A layout encapsulates a strategy for laying out data elements visually, relative to each other. It could be a simple as stacking bars in a chart (where the base of one bar depends on the height of any below it) or as complex as labeling a map (by shifting labels around until overlap with conflicting map features is minimized). Layouts take a set of input data, apply an algorithm or heuristic, and output the resulting positions/shapes for a cohesive display of the data.

Layouts are not unlike d3.svg path generators, in that they facilitate the conversion of data to display form. However, layouts typically operate across a collection of data as a whole, rather than individually. Furthermore, the results of a layout could be used anywhere, not just with SVG. Some layouts are even dynamic through time: for example, you .start() a d3.layout.force() instance and then listen for layout updates on 'tick' events.

Many layouts are built in to D3 itself:

• Bundle - apply Holten's hierarchical bundling algorithm to edges.
• Chord - produce a chord diagram from a matrix of relationships.
• Cluster - cluster entities into a dendrogram.
• Force - position linked nodes using physical simulation.
• Hierarchy - derive a custom hierarchical layout implementation.
• Histogram - compute the distribution of data using quantized bins.
• Pack - produce a hierarchical layout using recursive circle-packing.
• Partition - recursively partition a node tree into a sunburst or icicle.
• Pie - compute the start and end angles for arcs in a pie or donut chart.
• Stack - compute the baseline for each series in a stacked bar or area chart.
• Tree - position a tree of nodes tidily.
• Treemap - use recursive spatial subdivision to display a tree of nodes.

Layouts instances are sometimes functions (though not necessarily) that can be configured and then applied to a set of data. Other times, specific methods or event handlers are used for data input and position output. Please refer to the documentation of each particular layout for usage.