# nearestsegment

0th

Percentile

##### Find Line Segment Nearest to Each Point

Given a point pattern and a line segment pattern, this function finds the nearest line segment for each point.

Keywords
spatial, math
##### Usage
nearestsegment(X, Y)
##### Arguments
X
A point pattern (object of class "ppp").
Y
A line segment pattern (object of class "psp").
##### Details

The distance between a point x and a straight line segment y is defined to be the shortest Euclidean distance between x and any location on y. This algorithm first calculates the distance from each point of X to each segment of Y. Then it determines, for each point x in X, which segment of Y is closest. The index of this segment is returned.

##### Value

• Integer vector v (of length equal to the number of points in X) identifying the nearest segment to each point. If v[i] = j, then Y[j] is the line segment lying closest to X[i].

project2segment to project each point of X to a point lying on one of the line segments.

Use distmap.psp to identify the nearest line segment for each pixel in a grid.

##### Aliases
• nearestsegment
##### Examples
X <- runifpoint(3)
Y <- as.psp(matrix(runif(20), 5, 4), window=owin())
v <- nearestsegment(X,Y)
plot(Y)
plot(Y[v[1]], add=TRUE, lwd=2, col="red")