R: Search for the enclosing Delaunay convex hull

tsearch {geometry}

R Documentation

Search for the enclosing Delaunay convex hull

Description

For t = delaunay(cbind(x, y)), where (x, y) is a 2D set of points, tsearch(x, y, t, xi, yi) finds the index in t containing the points (xi, yi). For points outside the convex hull the index is NA.

Usage

tsearch(x, y, t, xi, yi, bary = FALSE)

Arguments

`x`	X-coordinates of triangluation points
`y`	Y-coordinates of triangluation points
`t`	Triangulation, e.g. produced by `t = delaunayn(cbind(x, y))`
`xi`	X-coordinates of points to test
`yi`	Y-coordinates of points to test
`bary`	If `TRUE` return barycentric coordinates as well as index of triangle.

Value

If bary is FALSE, the index in t containing the points (xi, yi). For points outside the convex hull the index is NA. If bary is TRUE, a list containing:

`list("idx")`	the index in `t` containing the points `(xi, yi)`
`list("p")`	a 3-column matrix containing the barycentric coordinates with respect to the enclosing triangle of each point code(xi, yi).

Note

Author(s)

David Sterratt