https://github.com/cran/pracma
Tip revision: f2b1a2b0b321bb40a034d89a636072cd71ad25cc authored by HwB on 21 November 2011, 00:00:00 UTC
version 0.8.6
version 0.8.6
Tip revision: f2b1a2b
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}.
}
\author{
HwB email: <hwborchers@googlemail.com>
}
\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 }