spatstat.linnet (version 3.4-0)

as.linim: Convert to Pixel Image on Linear Network

Description

Converts various kinds of data to a pixel image on a linear network.

Usage

as.linim(X, ...)
  # S3 method for linim
as.linim(X, ...)
  # S3 method for linfun
as.linim(X, L=domain(X), ...,
                            eps = NULL, dimyx = NULL, xy = NULL,
                            rule.eps=c("adjust.eps",
                                        "grow.frame", "shrink.frame"),
                            delta=NULL, nd=NULL)
  # S3 method for function
as.linim(X, L, ...,
                             eps = NULL, dimyx = NULL, xy = NULL,
                             rule.eps=c("adjust.eps",
                                        "grow.frame", "shrink.frame"),
                             delta=NULL, nd=NULL)
  # S3 method for default
as.linim(X, L, ...,
                             eps = NULL, dimyx = NULL, xy = NULL,
                             rule.eps=c("adjust.eps",
                                        "grow.frame", "shrink.frame"),
                             delta=NULL, nd=NULL)

Value

An image object on a linear network; an object of class "linim".

Details

This function converts the data X into a pixel image on a linear network, an object of class "linim" (see linim).

The argument X may be any of the following:

• a function on a linear network, an object of class "linfun".

• a pixel image on a linear network, an object of class "linim".

• a pixel image, an object of class "im".

• a function(x,y) in the R language.

• any type of data acceptable to as.im, such as a function, numeric value, or window.

First X is converted to a pixel image object Y (object of class "im"). The conversion is performed by as.im. The arguments eps, dimyx, xy and rule.eps determine the pixel resolution.

Next Y is converted to a pixel image on a linear network using linim. The argument L determines the linear network. If L is missing or NULL, then X should be an object of class "linim", and L defaults to the linear network on which X is defined.

In addition to converting the function to a pixel image, the algorithm also generates a fine grid of sample points evenly spaced along each segment of the network. The function values at these sample points are stored in the resulting object as a data frame (the argument df of linim). This mechanism allows greater accuracy for some calculations (such as integral.linim). If L is a "linim" object, then it is used as a template; the sample points are determined by the sample points in L. Otherwise, L is treated as a network (class "linnet"), and new sample points are constructed by placing them evenly-spaced along each segment of the network with separation delta.

See Also

as.im

Examples

  f <- function(x,y){ x + y }
  plot(as.linim(f, simplenet))