as.owin
Convert Data To Class owin
Converts data specifying an observation window
in any of several formats, into an object of class "owin"
.
Usage
as.owin(W, ..., fatal=TRUE) ## S3 method for class 'owin':
as.owin(W, \dots, fatal=TRUE)
## S3 method for class 'ppp':
as.owin(W, \dots, fatal=TRUE)
## S3 method for class 'ppm':
as.owin(W, \dots, fatal=TRUE)
## S3 method for class 'kppm':
as.owin(W, \dots, fatal=TRUE)
## S3 method for class 'lppm':
as.owin(W, \dots, fatal=TRUE)
## S3 method for class 'psp':
as.owin(W, \dots, fatal=TRUE)
## S3 method for class 'quad':
as.owin(W, \dots, fatal=TRUE)
## S3 method for class 'tess':
as.owin(W, \dots, fatal=TRUE)
## S3 method for class 'im':
as.owin(W, \dots, fatal=TRUE)
## S3 method for class 'gpc.poly':
as.owin(W, \dots, fatal=TRUE)
## S3 method for class 'data.frame':
as.owin(W, \dots, fatal=TRUE)
## S3 method for class 'distfun':
as.owin(W, \dots, fatal=TRUE)
## S3 method for class 'nnfun':
as.owin(W, \dots, fatal=TRUE)
## S3 method for class 'funxy':
as.owin(W, \dots, fatal=TRUE)
## S3 method for class 'rmhmodel':
as.owin(W, \dots, fatal=FALSE)
## S3 method for class 'default':
as.owin(W, \dots, fatal=TRUE)
Arguments
- 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.
Details
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 W
may be
- an object of class
"owin"
- a structure with entries
xrange
,yrange
specifying the$x$and$y$dimensions of a rectangle - a four-element vector
(interpreted as
(xmin, xmax, ymin, ymax)
) specifying the$x$and$y$dimensions of a rectangle - a structure with entries
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 classspp
used in the Venables and Ripleyspatial library. - an object of class
"gpc.poly"
from thegpclib package, representing a polygonal window. - an object of class
"ppp"
representing a point pattern. In this case, the object'swindow
structure will be extracted. - an object of class
"psp"
representing a line segment pattern. In this case, the object'swindow
structure will be extracted. - an object of class
"tess"
representing a tessellation. In this case, the object'swindow
structure will be extracted. - an object of class
"quad"
representing a quadrature scheme. In this case, the window of thedata
component will be extracted. - an object of class
"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 ofNA
, signifying that the pixel lies outside the window, is transformed into the logical valueFALSE
, which is the corresponding convention for window masks. - an object of class
"ppm"
or"kppm"
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. - an object of class
"lppm"
representing a fitted point process model on a linear network. In this case,as.owin
extracts the linear network and returns a window containing this network. - A
data.frame
with exactly three columns. Each row of the data frame corresponds to one pixel. Each row contains the$x$and$y$coordinates of a pixel, and a logical value indicating whether the pixel lies inside the window. - an object of class
"distfun"
,"nnfun"
or"funxy"
representing a function of spatial location, defined on a spatial domain. The spatial domain of the function will be extracted. - an object of class
"rmhmodel"
representing a point process model that can be simulated usingrmh
. The window (spatial domain) of the model will be extracted. The window may beNULL
in some circumstances (indicating that the simulation window has not yet been determined). This is not treated as an error, because the argumentfatal
defaults toFALSE
for this method.
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.
Value
- An object of class
"owin"
(seeowin.object
) specifying an observation window.
See Also
Examples
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)