Crossing Points of Two Line Segment Patterns
Finds any crossing points between two line segment patterns.
crossing.psp(A,B,fatal=TRUE,details=FALSE)
A,B |
Line segment patterns (objects of class |
details |
Logical value indicating whether to return additional information. See below. |
fatal |
Logical value indicating what to do
if the windows of |
This function finds any crossing points between
the line segment patterns A and B.
A crossing point occurs whenever one of the line segments in A
intersects one of the line segments in B, at a nonzero
angle of intersection.
The result is a point pattern consisting of all the intersection points.
If details=TRUE, additional information is computed,
specifying where each intersection point came from.
The resulting point pattern has a data frame of marks, with columns
named iA, jB, tA, tB. The marks iA
and jB are the indices of the line segments in A and
B, respectively, which produced each intersection point.
The marks tA and tB are numbers between 0 and 1
specifying the position of the intersection point along the
original segments.
If the windows Window(A) and Window(B) do not
overlap, then an error will be reported if fatal=TRUE,
while if fatal=FALSE an error will not occur
and the result will be NULL.
Point pattern (object of class "ppp").
Adrian Baddeley Adrian.Baddeley@curtin.edu.au and Rolf Turner r.turner@auckland.ac.nz
a <- psp(runif(10), runif(10), runif(10), runif(10), window=owin()) b <- psp(runif(10), runif(10), runif(10), runif(10), window=owin()) plot(a, col="green", main="crossing.psp") plot(b, add=TRUE, col="blue") P <- crossing.psp(a,b) plot(P, add=TRUE, col="red") as.data.frame(crossing.psp(a,b,details=TRUE))
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