Class of Line Segment Patterns
A class "psp" to represent a spatial pattern of
line segments in the plane.
Includes information about the window in which the
pattern was observed. Optionally includes marks.
An object of this class represents a two-dimensional pattern of line segments. It specifies
the locations of the line segments (both endpoints)
the window in which the pattern was observed
optionally, a “mark” attached to each line segment (extra information such as a type label).
If X is an object of type psp,
it contains the following elements:
ends |
data frame with entries x0, y0, x1, y1 |
| giving coordinates of segment endpoints | |
window |
window of observation |
(an object of class owin) |
|
n |
number of line segments |
marks |
optional vector or data frame of marks |
markformat |
character string specifying the format of the |
| marks; “none”, “vector”, or “dataframe” |
Users are strongly advised not to manipulate these entries directly.
There are also methods for summary and print
for line segment patterns. Use summary(X) to see a useful description
of the data.
Utilities for line segment patterns include
midpoints.psp (to compute the midpoints of each segment),
lengths_psp, (to compute the length of each segment),
angles.psp, (to compute the angle of orientation of
each segment), and
distmap.psp to compute the distance map of a
line segment pattern.
Adrian Baddeley Adrian.Baddeley@curtin.edu.au
and Rolf Turner r.turner@auckland.ac.nz
# creating
a <- psp(runif(20),runif(20),runif(20),runif(20), window=owin())
# converting from other formats
a <- as.psp(matrix(runif(80), ncol=4), window=owin())
a <- as.psp(data.frame(x0=runif(20), y0=runif(20),
x1=runif(20), y1=runif(20)), window=owin())
# clipping
w <- owin(c(0.1,0.7), c(0.2, 0.8))
b <- clip.psp(a, w)
b <- a[w]
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