spatstat (version 1.31-3)

plot.owin: Plot a Spatial Window

Description

Plot a two-dimensional window of observation for a spatial point pattern

Usage

## S3 method for class 'owin':
plot(x, main, add=FALSE, \dots, box, edge=0.04,
                      hatch=FALSE, angle=45, spacing=diameter(x)/50,
                      invert=FALSE)

Arguments

x

The window to be plotted. An object of class owin, or data which can be converted into this format by as.owin().

main

text to be displayed as a title above the plot.

add

logical flag: if TRUE, draw the window in the current plot; if FALSE, generate a new plot.

...

extra arguments passed to the generic plot function.

box

logical flag; if TRUE, plot the enclosing rectangular box

edge

nonnegative number; the plotting region will have coordinate limits that are 1 + edge times as large as the limits of the rectangular box that encloses the pattern.

hatch

logical flag; if TRUE, the interior of the window will be shaded by a grid of parallel lines.

angle

orientation of the shading lines (in degrees anticlockwise from the $x$ axis) when hatch=TRUE.

spacing

spacing between the shading lines, when hatch=TRUE.

invert

logical flag; when the window is a binary pixel mask, the mask colours will be inverted if invert=TRUE.

Value

• none.

Cairo graphics on a Linux system

Linux systems support the graphics device X11(type="cairo") (see X11) provided the external library cairo is installed on the computer. See http://www.cairographics.org/download for instructions on obtaining and installing cairo. After having installed cairo one needs to re-install Rfrom source so that it has cairo capabilites. To check whether your current installation of R has cairo capabilities, type (in R) capabilities()["cairo"]. The default type for X11 is controlled by X11.options. You may find it convenient to make cairo the default, e.g. via your .Rprofile. The magic incantation to put into .Rprofile is setHook(packageEvent("graphics", "onLoad"), function(...) grDevices::X11.options(type="cairo"))

Details

This is the plot method for the class owin. The action is to plot the boundary of the window on the current plot device, using equal scales on the x and y axes.

If the window x is of type "rectangle" or "polygonal", the boundary of the window is plotted as a polygon or series of polygons. If x is of type "mask" the discrete raster approximation of the window is displayed as a binary image (white inside the window, black outside).

Graphical parameters controlling the display (e.g. setting the colours) may be passed directly via the ... arguments, or indirectly reset using spatstat.options.

When x is of type "rectangle" or "polygonal", it is plotted by the Rfunction polygon. To control the appearance (colour, fill density, line density etc) of the polygon plot, determine the required argument of polygon and pass it through ... For example, to paint the interior of the polygon in red, use the argument col="red". To draw the polygon edges in green, use border="green". To suppress the drawing of polygon edges, use border=NA.

When x is of type "mask", it is plotted by image.default. The appearance of the image plot can be controlled by passing arguments to image.default through .... The default appearance can also be changed by setting the parameter par.binary of spatstat.options.

To zoom in (to view only a subset of the window at higher magnification), use the graphical arguments xlim and ylim to specify the desired rectangular field of view. (The actual field of view may be larger, depending on the graphics device).

See Also

owin.object, plot.ppp, polygon, image.default, spatstat.options

Examples

# rectangular window
   data(nztrees)
   plot(nztrees$window)
   abline(v=148, lty=2)

  # polygonal window
  data(demopat)
  w <- demopat$window
  plot(w)
  plot(w, col="red", border="green", lwd=2)
  plot(w, hatch=TRUE, lwd=2)

  # binary mask
  we <- as.mask(erosion(w, 400, FALSE))
  plot(we)
  op <- spatstat.options(par.binary=list(col=grey(c(0.5,1))))
  plot(we)
  spatstat.options(op)