R: Plot Pixel Image on Linear Network

plot.linim {spatstat} | R Documentation

## Plot Pixel Image on Linear Network

### Description

Given a pixel image on a linear network, the pixel values are displayed either as colours or as line widths.

### Usage

    ## S3 method for class 'linim'
    plot(x, ..., style = c("colour", "width"),
                 scale, adjust = 1,
                 negative.args = list(col=2),
                 legend=TRUE,
                 leg.side=c("right", "left", "bottom", "top"),
                 leg.sep=0.1,
                 leg.wid=0.1,
                 leg.args=list(),
                 leg.scale=1,
                 zlim,
                 do.plot=TRUE)

### Arguments

`x` | The pixel image to be plotted. An object of class `"linim"`.
`...` | Extra graphical parameters, passed to `plot.im` if `style="colour"`, or to `polygon` if `style="width"`.
`style` | Character string specifying the type of plot. See Details.
`scale` | Physical scale factor for representing the pixel values as line widths.
`adjust` | Adjustment factor for the default scale.
`negative.args` | A list of arguments to be passed to `polygon` specifying how to plot negative values of `x` when `style="width"`.
`legend` | Logical value indicating whether to plot a legend (colour ribbon or scale bar).
`leg.side` | Character string indicating where to display the legend relative to the main image.
`leg.sep` | Factor controlling the space between the legend and the image.
`leg.wid` | Factor controlling the width of the legend.
`leg.scale` | Rescaling factor for annotations on the legend. The values on the numerical scale printed beside the legend will be multiplied by this rescaling factor.
`leg.args` | List of additional arguments passed to `image.default`, `axis` or `text.default` to control the display of the legend. These may override the `...` arguments.
`zlim` | The range of numerical values that should be mapped. A numeric vector of length 2. Defaults to the range of values of `x`.
`do.plot` | Logical value indicating whether to actually perform the plot.

### Details

This is the `plot` method for objects of class `"linim"`. Such an object represents a pixel image defined on a linear network.

If `style="colour"` (the default) then the pixel values of `x` are plotted as colours, using `plot.im`.

If `style="width"` then the pixel values of `x` are used to determine the widths of thick lines centred on the line segments of the linear network.

### Value

If `style="colour"`, the result is an object of class `"colourmap"` specifying the colour map used. If `style="width"`, the result is a numeric value `v` giving the physical scale: one unit of pixel value is represented as `v` physical units on the plot.

The result also has an attribute `"bbox"` giving a bounding box for the plot. The bounding box includes the ribbon or scale bar, if present, but not the main title.

### Author(s)

Adrian Baddeley Adrian.Baddeley@curtin.edu.au

### References

Ang, Q.W., Baddeley, A. and Nair, G. (2012) Geometrically corrected second-order analysis of events on a linear network, with applications to ecology and criminology. Scandinavian Journal of Statistics 39, 591–617.

### See Also

`linim`, `plot.im`, `polygon`

### Examples

      X <- linfun(function(x,y,seg,tp){y^2+x}, simplenet)
      X <- as.linim(X)

      plot(X)
      plot(X, style="width", main="Width proportional to function value")

      # signed values
      f <- linfun(function(x,y,seg,tp){y-x}, simplenet)
      plot(f, style="w", main="Negative values in red")

      plot(f, style="w", negative.args=list(density=10),
           main="Negative values are hatched")

[Package spatstat version 1.54-0 Index]