pairdist.lpp {spatstat.linnet}

Pairwise shortest-path distances between points on a linear network

Description

Given a pattern of points on a linear network, compute the matrix of distances between all pairs of points, measuring distance by the shortest path in the network.

Usage

## S3 method for class 'lpp'
pairdist(X, ..., method="C")

Arguments

X

Point pattern on linear network (object of class "lpp").

method

Optional string determining the method of calculation. Either "interpreted" or "C".

...

Ignored.

Details

Given a pattern of points on a linear network, this function computes the matrix of distances between all pairs of points, measuring distance by the shortest path in the network.

If two points cannot be joined by a path, the distance between them is infinite (Inf).

The argument method is not normally used. It is retained only for developers to check the validity of the software.

Value

A symmetric matrix, whose values are nonnegative numbers or infinity (Inf).

Algorithms and accuracy

Distances are accurate within the numerical tolerance of the network, summary(X)$toler.

For network data stored in the non-sparse representation described in linnet, then pairwise distances are computed using the matrix of path distances between vertices of the network, using R code if method = "interpreted", or using C code if method="C" (the default).

For networks stored in the sparse representation, the argument method has no effect, and the distances are computed using an efficient C algorithm.

Author(s)

Ang Qi Wei [e-mail] and Adrian Baddeley [e-mail].

See Also

lpp

Examples

   X <- runiflpp(12, simplenet)
   d <- pairdist(X)
   d[1:3, 1:3]