bdist.pixels
From spatstat v1.480
by Adrian Baddeley
Distance to Boundary of Window
Computes the distances from each pixel in a window to the boundary of the window.
Usage
bdist.pixels(w, ..., style="image")
Arguments
 w
 A window (object of class
"owin"
).  ...
 Arguments passed to
as.mask
to determine the pixel resolution.  style
 Character string determining the format of
the output: either
"matrix"
,"coords"
or"image"
.
Details
This function computes, for each pixel $u$
in the window w
, the shortest distance
$dist(u, W')$ from $u$
to the boundary of $W$.
If the window is not of type "mask"
then it is first
converted to that type. The arguments "\dots"
are
passed to as.mask
to determine the pixel resolution.
Value

If
style="image"
, a pixel image (object of class "im"
)
containing the distances from each pixel in the image raster
to the boundary of the window.If style="matrix"
,
a matrix giving the distances from each pixel in the image raster
to the boundary of the window. Rows of this matrix correspond to
the $y$ coordinate and columns to the $x$ coordinate.If style="coords"
, a list with three components
x,y,z
, where x,y
are vectors of length $m,n$
giving the $x$ and $y$ coordinates respectively,
and z
is an $m x n$ matrix such that
z[i,j]
is the distance from (x[i],y[j])
to the
boundary of the window. Rows of this matrix correspond to the
$x$ coordinate and columns to the $y$ coordinate.
This result can be plotted with persp
, image
or contour
.
See Also
Examples
u < owin(c(0,1),c(0,1))
d < bdist.pixels(u, eps=0.01)
image(d)
d < bdist.pixels(u, eps=0.01, style="matrix")
mean(d >= 0.1)
# value is approx (1  2 * 0.1)^2 = 0.64
Community examples
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