Window
Extract or Change the Window of a Spatial Object
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 ppp
Window(X, …)
# S3 method for ppp
Window(X, …) <- value
# S3 method for psp
Window(X, …)
# S3 method for psp
Window(X, …) <- value
# S3 method for im
Window(X, …)
# S3 method for im
Window(X, …) <- 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 forX
.
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:
If
X
is a point pattern (object of class"ppp"
) thenWindow(X) <- W
discards any points ofX
which fall outsideW
.If
X
is a line segment pattern (object of class"psp"
) thenWindow(X) <- W
clips the segments ofX
to the boundaries ofW
.If
X
is a pixel image (object of class"im"
) thenWindow(X) <- W
has the effect that pixels lying outsideW
are 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
.
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
.
See Also
Examples
# NOT RUN {
## 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)
# }