spatstat (version 1.31-3)

lpp: Create Point Pattern on Linear Network

Description

Creates an object of class "lpp" that represents a point pattern on a linear network.

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 to as.ppp.

L

Linear network (object of class "linnet").

Value

• An object of class "lpp". Also inherits the class "ppx".

Note on changed format

The internal format of "lpp" objects was changed in spatstat version 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)).

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 ofXwill be interpreted as spatial coordinates, and any remaining columns as marks.
• The exception occurs ifXis 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.

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)