distancePointToPoint: Finds the distance between two points or sets of points

Description

Finds the distance betweeen two single points, the distances between one point and a set of points, or the distances between two point sets. Points can be of any number of dimensions.

Usage

distancePointToPoint(p1, p2 = NULL)

Arguments

a vector of a single point or a matrix of one or multiple points

a vector of a single point or a matrix of one or multiple points. If NULL, the function either returns the distance of p1 from the origin or the distances between subsequent values of p1.

Value

a vector of distance(s)

Details

If p1 is a single point and p2 is a single point then the function returns the distance between these two points. If either p1 or p2 is a single point and the other is a matrix of multiple points then the function returns a vector of the distances between the single point and each of the multiple points. If both p1 and p2 are matrices of multiple points, then the function returns a vector of the distances between the points in each corresponding row. If p1 and p2 are both matrices, the matrix dimensions must match.

If p2 is NULL, then distancePointToPoint() returns the distance between consecutive points in p1. If p1 is a vector, the function returns the absolute difference between consecutive values of p1 (interpoint distances along a single dimension). If p1 is a matrix, then the function returns the distance between the point in each row of p1 and its subsequent row. This can be used to return the interpoint distances along a curve defined as a matrix of points.

Examples

Run this code

# NOT RUN {
## FIND THE DISTANCE BETWEEN TWO, 2D POINTS
## VALUE IS sqrt(2)
distancePointToPoint(p1=c(0, 0), p2=c(1, 1))

## FIND THE DISTANCE BETWEEN A 2D POINT AND MULTIPLE 2D POINTS
p1 <- c(0, 0)
p2 <- matrix(c(1, 1, 2, 2, 3, 3), nrow=3, ncol=2, byrow=TRUE)
distancePointToPoint(p1=p1, p2=p2)

## FIND THE DISTANCE BETWEEN TWO SETS OF 2D POINTS
p1 <- matrix(c(0, 0, 1, 1, 2, 2), nrow=3, ncol=2, byrow=TRUE)
p2 <- matrix(c(1, 1, 2, 2, 3, 3), nrow=3, ncol=2, byrow=TRUE)
distancePointToPoint(p1=p1, p2=p2)

## FIND THE DISTANCE BETWEEN A 3D POINT AND MULTIPLE 3D POINTS
p1 <- c(0, 0, 0)
p2 <- matrix(c(1, 1, 1, 2, 2, 2, 3, 3, 3), nrow=3, ncol=3, byrow=TRUE)
distancePointToPoint(p1=p1, p2=p2)

## FIND THE DISTANCE BETWEEN CONSECUTIVE VALUES IN A VECTOR
distancePointToPoint(p1=c(1, 2, 4, 7))

## FIND THE DISTANCE BETWEEN CONSECUTIVE 2D POINTS IN A MATRIX
## HERE, WE FIND THE DISTANCE BETWEEN THE POINT c(0, 0) AND c(1, 1), WHICH IS sqrt(2)
distancePointToPoint(p1=matrix(c(0, 0, 1, 1), nrow=2, ncol=2, byrow=TRUE))

## FIND THE DISTANCE BETWEEN CONSECUTIVE 2D POINTS IN A MATRIX, WITH MORE POINTS
## HERE, WE ADD TWO MORE POINTS TO THE PREVIOUS EXAMPLE: c(2, 2) AND c(3, 3)
## THE DISTANCE BETWEEN EACH CONSECUTIVE PAIR OF POINTS IS sqrt(2)
distancePointToPoint(p1=matrix(c(0, 0, 1, 1, 2, 2, 3, 3), nrow=4, ncol=2, byrow=TRUE))

## FIND THE DISTANCE BETWEEN CONSECUTIVE 3D POINTS IN A MATRIX
distancePointToPoint(p1=matrix(c(0, 0, 0, 1, 1, 1), nrow=2, ncol=3, byrow=TRUE))

## FIND THE DISTANCE BETWEEN CONSECUTIVE 4D POINTS IN A MATRIX
distancePointToPoint(p1=matrix(c(0, 0, 0, 0, 1, 1, 1, 1), nrow=2, ncol=4, byrow=TRUE))
# }