lpp
Create Point Pattern on Linear Network
Creates an object of class "lpp" that represents
a point pattern on a linear network.
- Keywords
- spatial
Usage
lpp(X, L)Arguments
- X
- Locations of the points. A matrix or data frame of coordinates,
or a point pattern object (of class
"ppp") or other data acceptable toas.ppp. - L
- Linear network (object of class
"linnet").
Details
This command creates an object of class "lpp" that represents
a point pattern on a linear network.
Normally X is a point pattern. The points of X should lie
on the lines of L.
Alternatively X may be a matrix or data frame containing at
least two columns.
- Usually
the first two columns of
Xwill be interpreted as spatial coordinates, and any remaining columns as marks. - The exception occurs if
Xis a data frame with columns namedx,y,segandtp. Thenxandywill be interpreted as spatial coordinates, andsegandtpas local coordinates, withsegindicating which line segment ofLthe point lies on, andtpindicating how far along the segment the point lies (normalised to 1). Any remaining columns will be interpreted as marks.
Value
- An object of class
"lpp". Also inherits the class"ppx".
Note on changed format
The internal format of "lpp" objects was changed in
1.28-0.
Objects in the old format are still handled correctly,
but computations are faster in the new format.
To convert an object X from the old format to the new format,
use X <- lpp(as.ppp(X), as.linnet(X)).
See Also
intensity.lpp,
methods.lpp and
methods.ppx for methods applicable
to lpp objects.
linnet for linear networks.
Random point patterns on a linear network can be generated by
rpoislpp or runiflpp.
Examples
example(linnet)
xx <- list(x=c(-1.5,0,0.5,1.5), y=c(1.5,3,4.5,1.5))
X <- lpp(xx, letterA)
plot(X)
X
summary(X)