link.hull Function (GPL)

Syntax

link.hull(<algebra>)

or 

link.hull(<binning function>)

or 

link.hull(<statistic function>)

<algebra>. Graph algebra, such as x*y. Refer to Brief Overview of GPL Algebra for an introduction to graph algebra.

<binning function>. A binning function.

<statistic function>. Another statistic function. The result of the embedded statistic is used to calculate link.hull.

Description

Calculates the convex hull around the values. This function is typically used with the edge graphic element. A convex hull connects the least number of outermost values so that the hull contains all values. The hull contains all possible connections between any two values. Note that the convex hull is the boundary of the Delaunay triangulation.

Examples

Figure 1. Example: Creating a convex hull
ELEMENT: edge(position(link.hull(x*y)))

Statistic Functions

See GPL Functions .