eroded.areas {spatstat.geom} | R Documentation |
Areas of Morphological Erosions
Description
Computes the areas of successive morphological erosions of a window.
Usage
eroded.areas(w, r, subset=NULL)
Arguments
w |
A window. |
r |
Numeric vector of radii at which erosions will be performed. |
subset |
Optional window inside which the areas should be computed. |
Details
This function computes the areas of the erosions of the window
w
by each of the radii r[i]
.
The morphological erosion of a set W
by a distance r > 0
is the subset
consisting of all points x \in W
such that the
distance from x
to the boundary of W
is greater than
or equal to r
. In other words it is the result of trimming
a margin of width r
off the set W
.
The argument r
should be a vector of positive numbers.
The argument w
should be a window (an object of class
"owin"
, see owin.object
for details)
or can be given in any format acceptable to as.owin()
.
Unless w
is a rectangle, the computation is performed
using a pixel raster approximation.
To compute the eroded window itself, use erosion
.
Value
Numeric vector, of the same length as r
,
giving the areas of the successive erosions.
Author(s)
Adrian Baddeley Adrian.Baddeley@curtin.edu.au
and Rolf Turner rolfturner@posteo.net
See Also
Examples
w <- owin(c(0,1),c(0,1))
a <- eroded.areas(w, seq(0.01,0.49,by=0.01))