rpoisppOnLines {spatstat} | R Documentation |
Given a line segment pattern, generate a Poisson random point pattern on the line segments.
rpoisppOnLines(lambda, L, lmax = NULL, ...)
lambda |
Intensity of the Poisson process.
A single number, a |
L |
Line segment pattern (object of class |
lmax |
Maximum possible value of |
... |
Additional arguments passed to |
This command generates a Poisson point process on the one-dimensional
system of line segments in L
. The result is a point pattern
consisting of points lying on the line segments in L
.
The number of random points falling on any given line segment follows
a Poisson distribution. The patterns of points on different segments
are independent.
The intensity lambda
is the expected number of points
per unit length of line segment.
It may be constant, or it may depend on spatial location.
The argument lambda
may be a single number,
or a function(x,y)
, or a pixel image (object of class
"im"
). In the two latter cases, the rejection method is used.
The rejection method requires knowledge of lmax
,
the maximum possible value of lambda
. If lmax
is not
given, it will be computed approximately, by sampling many values of
lambda
.
A point pattern (object of class "ppp"
) in the same window
as L
.
Adrian Baddeley Adrian.Baddeley@csiro.au http://www.maths.uwa.edu.au/~adrian/ and Rolf Turner r.turner@auckland.ac.nz
psp
,
ppp
,
runifpointOnLines
,
rpoispp
L <- psp(runif(10), runif(10), runif(10), runif(10), window=owin()) plot(L, main="") # uniform intensity Y <- rpoisppOnLines(4, L) plot(Y, add=TRUE, pch="+") # intensity is a function Y <- rpoisppOnLines(function(x,y){ 10 * x^2}, L, 10) plot(L, main="") plot(Y, add=TRUE, pch="+") # intensity is an image Z <- as.im(function(x,y){10 * sqrt(x+y)}, unit.square()) Y <- rpoisppOnLines(Z, L, 10) plot(L, main="") plot(Y, add=TRUE, pch="+")