SimilarityMeasures (version 1.4)

FrechetCheck: Checks a Frechet Leash Distance

Description

A function to check whether a Frechet leash distance is successful or not. This is used by the Frechet calculation and does not need to be called directly.

Usage

FrechetCheck(traj1, traj2, leash, dist1, dist2, distSq12)

Arguments

traj1

An m x n matrix containing trajectory1. Here m is the number of points and n is the dimension of the points.

traj2

A k x n matrix containing trajectory2. Here k is the number of points and n is the dimension of the points. The two trajectories are not required to have the same number of points.

leash

A numeric leash value to be checked by the function.

dist1

A vector containing the distance between each successive two points in trajectory1.

dist2

A vector containing the distance between each successive two points in trajectory2.

distSq12

A matrix containing the distance between each pair of two points where 1 point lies in trajectory1 and the other in trajectory2.

Value

A boolean value is returned. A value of true is returned if the leash is successful and false if not.

Details

This function is required by Frechet and in general does not need to be called directly.

References

Alt, H. and Godau, M. (1995) Computing the Frechet distance between two polygonal curves. International Journal of Computational Geometry & Applications, 5(01n02), 75--91.

See Also

Frechet

Examples

# Creating two trajectories.
path1 <- matrix(c(0, 1, 2, 3, 0, 1, 2, 3), 4)
path2 <- matrix(c(0, 1, 2, 3, 4, 5, 6, 7), 4)

# Running the Frechet distance algorithm with a test leash of 2.
Frechet(path1, path2, 2)