spatstat (version 1.41-1)

Window: Extract or Change the Window of a Spatial Object

Description

Given a spatial object (such as a point pattern or pixel image) in two dimensions, these functions extract or change the window in which the object is defined.

Usage

Window(X, ...)
   Window(X, ...) <- value
   ## S3 method for class 'ppp':
Window(X, \dots)
   ## S3 method for class 'ppp':
Window(X, \dots) <- value
   ## S3 method for class 'psp':
Window(X, \dots)
   ## S3 method for class 'psp':
Window(X, \dots) <- value
   ## S3 method for class 'im':
Window(X, \dots)
   ## S3 method for class 'im':
Window(X, \dots) <- value

Arguments

X

A spatial object such as a point pattern, line segment pattern or pixel image.

...

Extra arguments. They are ignored by all the methods listed here.

value

Another window (object of class "owin") to be used as the window for X.

Value

• The result of Window is a window (object of class "owin").

  The result of Window<- is the updated object X, of the same class as X.

Details

The functions Window and Window<- are generic.

Window(X) extracts the spatial window in which X is defined.

Window(X) <- W changes the window in which X is defined to the new window W, and discards any data outside W. In particular:

• IfXis a point pattern (object of class"ppp") thenWindow(X) <- Wdiscards any points ofXwhich fall outsideW.
• IfXis a line segment pattern (object of class"psp") thenWindow(X) <- Wclips the segments ofXto the boundaries ofW.
• IfXis a pixel image (object of class"im") thenWindow(X) <- Whas the effect that pixels lying outsideWare retained but their pixel values are set toNA.

Many other classes of spatial object have a method for Window, but not Window<-. See Window.ppm.

See Also

Window.ppm

Examples

## point patterns
   Window(cells)
   X <- demopat
   Window(X)
   Window(X) <- as.rectangle(Window(X))

   ## line segment patterns
   X <- psp(runif(10), runif(10), runif(10), runif(10), window=owin())
   Window(X)
   Window(X) <- square(0.5)

   ## images
   Z <- setcov(owin())
   Window(Z)
   Window(Z) <- square(0.5)