https://github.com/cran/pracma
Tip revision: d57c14d79af36feb7376258875e720ceffcc1312 authored by Hans W. Borchers on 11 October 2014, 00:00:00 UTC
version 1.7.3
version 1.7.3
Tip revision: d57c14d
segm_distance.Rd
\name{segm_distance}
\alias{segm_distance}
\title{
Segment Distance
}
\description{
The minimum distance between a point and a segment, or the
minimum distance between points of two segments.
}
\usage{
segm_distance(p1, p2, p3, p4 = c())
}
\arguments{
\item{p1, p2}{end points of the first segment.}
\item{p3, p4}{end points of the second segment, or the point \code{p3}
alone if \code{p4} is \code{NULL}.}
}
\details{
If \code{p4=c()}, determines the orthogonal line to the segment through
the single point and computes the distance to the intersection point.
Otherwise, it computes the distances of all four end points to the
other segment and takes the minimum of those.
}
\value{
Returns a list with component \code{l} the minimum distance and components
\code{p, q} the two nearest points.
If \code{p4=c()} then point \code{p} lies on the segment and \code{q} is
\code{p4}.
}
\note{
The interfaces of \code{segm_intersect} and \code{segm_distance} should be
brought into line.
}
\seealso{
\code{\link{segm_intersect}}
}
\examples{
\dontrun{
plot(c(0, 1), c(0, 1), type = "n", asp=1,
xlab = "", ylab = "", main = "Segment Distances")
grid()
for (i in 1:20) {
s1 <- matrix(runif(4), 2, 2)
s2 <- matrix(runif(4), 2, 2)
lines(s1[, 1], s1[, 2], col = "red")
lines(s2[, 1], s2[, 2], col = "darkred")
S <- segm_distance(s1[1,], s1[2,], s2[1,], s2[2,])
S$d
points(c(S$p[1], S$q[1]), c(S$p[2], S$q[2]), pch=20, col="navy")
lines(c(S$p[1], S$q[1]), c(S$p[2], S$q[2]), col="gray")
}}
}
\keyword{ geom }