| as.owin {spatstat} | R Documentation |
Converts data specifying an observation window
in any of several formats, into an object of class "owin".
as.owin(W, ..., fatal=TRUE) ## S3 method for class 'owin': as.owin(W, ..., fatal=TRUE) ## S3 method for class 'ppp': as.owin(W, ..., fatal=TRUE) ## S3 method for class 'ppm': as.owin(W, ..., fatal=TRUE) ## S3 method for class 'im': as.owin(W, ..., fatal=TRUE) ## Default S3 method: as.owin(W, ..., fatal=TRUE)
W |
Data specifying an observation window, in any of several formats described under Details below. |
fatal |
Logical flag determining what to do if the data cannot be converted to an observation window. See Details. |
... |
Ignored. |
The class "owin" is a way of specifying the observation window
for a point pattern. See owin.object for an overview.
This function converts data in any of several formats
into an object of class "owin" for use by the spatstat
package. The argument W may be
"owin"
xrange, yrange specifying the
x and y dimensions of a rectangle
(xmin, xmax, ymin, ymax))
specifying the x and y dimensions of a rectangle
xl, xu, yl, yu
specifying the x and y dimensions of a rectangle
as (xmin, xmax) = (xl, xu) and
(ymin, ymax) = (yl, yu). This will accept objects of
class spp used in the Venables and Ripley spatial
library.
"ppp" representing a point pattern.
In this case, the object's window structure will be
extracted.
"im" representing a pixel image.
In this case, a window of type "mask" will be returned,
with the same pixel raster coordinates as the image.
An image pixel value of NA, signifying that the pixel
lies outside the window, is transformed into the logical value
FALSE, which is the corresponding convention for window masks.
"ppm" representing a fitted point process
model. In this case, as.owin extracts the original point
pattern data to which the model was fitted, and returns the
observation window of this point pattern.
If the argument W is not in one of these formats
and cannot be converted to a window, then an error will
be generated (if fatal=TRUE) or a value of NULL
will be returned (if fatal=FALSE).
The function as.owin is generic, with methods for
"owin",
"im" and
"ppp" as well as the default method.
An object of class "owin" (see owin.object)
specifying an observation window.
Adrian Baddeley adrian@maths.uwa.edu.au http://www.maths.uwa.edu.au/~adrian/ and Rolf Turner rolf@math.unb.ca http://www.math.unb.ca/~rolf
w <- as.owin(c(0,1,0,1))
w <- as.owin(list(xrange=c(0,5),yrange=c(0,10)))
# point pattern
data(demopat)
w <- as.owin(demopat)
# image
Z <- as.im(function(x,y) { x + 3}, unit.square())
w <- as.owin(Z)
# Venables & Ripley 'spatial' package
require(spatial)
towns <- ppinit("towns.dat")
w <- as.owin(towns)
detach(package:spatial)