layout.data Function (GPL)

Syntax

layout.data(<algebra>, <function>)

or 

layout.data(<function>))

<algebra>. Graph algebra, such as x*y. Refer to Brief Overview of GPL Algebra for an introduction to graph algebra. Unlike other network graphs, the algebra determines the position of elements and ties the position to a specific coordinate value (such as a value on a dimension). You can omit the algebra for edges if you are using algebra in another ELEMENT statement to specify the position of the points.

<functions>. Valid functions. The from and to functions are required. The node function is optional for edges, allowing you to draw edges without a separate node data source.

Description

Lays out graphic elements in the coordinate positions specified by the data. The function is used for network graphs, which are visual representations of data that consist of nodes and relations between nodes (edges).

Note: Network graphs that display nodes and edges require two data sources, one for the unique nodes and one for the edges. If the edge data source includes weights and the weight variable is indicated in the SOURCE statement, the weights influence the length of edges in the graph, with higher weights having shorter edges.

Examples

Figure 1. Example: Creating a network diagram
ELEMENT: point(position(layout.data(x*y, node(id), from(fromVar), to(toVar))), label(id))
ELEMENT: edge(position(layout.data(node(id), from(fromVar), to(toVar))))