dilated.areas {spatstat.geom} | R Documentation |
Areas of Morphological Dilations
Description
Computes the areas of successive morphological dilations.
Usage
dilated.areas(X, r, W=as.owin(X), ..., constrained=TRUE, exact = FALSE)
Arguments
X |
Object to be dilated.
A point pattern (object of class |
r |
Numeric vector of radii for the dilations. |
W |
Window (object of class |
... |
Arguments passed to |
constrained |
Logical flag indicating whether areas should be restricted
to the window |
exact |
Logical flag indicating whether areas should be computed
using analytic geometry (which is slower but more accurate).
Currently available only when |
Details
This function computes the areas of the dilations of X
by each of the radii r[i]
. Areas may also be computed
inside a specified window W
.
The morphological dilation of a set X
by a distance r > 0
is the subset
consisting of all points x
such that the
distance from x
to X
is less than
or equal to r
.
When X
is a point pattern, the dilation by a distance
r
is the union of
discs of radius r
centred at the points of X
.
The argument r
should be a vector of nonnegative numbers.
If exact=TRUE
and if X
is a point pattern,
then the areas are computed using analytic geometry, which is
slower but much more accurate. Otherwise the computation is performed
using distmap
.
To compute the dilated object itself, use dilation
.
Author(s)
Adrian Baddeley Adrian.Baddeley@curtin.edu.au
and Rolf Turner rolfturner@posteo.net
See Also
owin
,
as.owin
,
dilation
,
eroded.areas
Examples
X <- runifrect(10)
a <- dilated.areas(X, c(0.1,0.2), W=square(1), exact=TRUE)