LinkPath Transform

The linkpath transform is used to route a visual link between two nodes. The most common use case is to draw edges in a tree or network layout. By default links are simply straight lines between source and target nodes; however, with additional shape and orientation information, a variety of link paths can be expressed. This transform writes one property to each datum, providing an SVG path string for the link path.

Example

View Source Export PNG Export SVG

Transform Parameters

Property	Type	Description
sourceX	Field	The data field for the source x-coordinate. The default is `source.x`.
sourceY	Field	The data field for the source y-coordinate. The default is `source.y`.
targetX	Field	The data field for the target x-coordinate. The default is `target.x`.
targetY	Field	The data field for the target y-coordinate. The default is `target.y`.
orient	String	The orientation of the link path. One of `vertical` (default), `horizontal` or `radial`. If a `radial` orientation is specified, x and y coordinate parameters will instead be interpreted as an angle (in radians) and radius, respectively.
shape	String	The shape of the link path. One of `line` (default), `arc`, `curve`, `diagonal`, or `orthogonal`.
require	Signal	≥ 4.3 A required signal that this transform depends on. This parameter is needed if source or target coordinate values are set as a non-propagating side-effect of a transform in a different data stream (such as a force transform). In such cases the upstream transform should be bound to a signal and required by the linkpath transform.
as	String	The output field for the link path. The default is `"path"`.

Usage

{"type": "linkpath"}

Computes straight-line link paths using the default source and target coordinate fields. Writes the result to the path field.

{
  "type": "linkpath",
  "orient": "radial",
  "sourceX": "source.angle",
  "sourceY": "source.radius",
  "targetX": "target.angle",
  "targetY": "target.radius",
  "shape": "orthogonal",
  "as": "linkpath"
}

Computes link paths in polar coordinates ("orient": "radial") using the provided source and target coordinate fields. Link paths are routed along orthogonal lines, as in a cluster plot or dendrogram. Writes the result to the linkpath field.