Convert a Window to a Polygonal Window
Given a window W of any geometric type (rectangular,
polygonal or binary mask), this function returns a polygonal window
that represents the same spatial domain.
as.polygonal(W, repair=FALSE)
W |
A window (object of class |
repair |
Logical value indicating whether to check the validity
of the polygon data and repair it,
if |
Given a window W of any geometric type (rectangular,
polygonal or binary mask), this function returns a polygonal window
that represents the same spatial domain.
If W is a rectangle, it is converted to a polygon with
4 vertices.
If W is already polygonal, it is returned unchanged, by default.
However if repair=TRUE then the validity of the polygonal coordinates
will be checked (for example to check the boundary is not self-intersecting)
and repaired if necessary, so that the result could be different
from W.
If W is a binary mask, then each pixel in the
mask is replaced by a small square or rectangle, and the union of these
squares or rectangles is computed. The result is a polygonal window
that has only horizontal and vertical edges.
(Use simplify.owin to remove the staircase
appearance, if desired).
A polygonal window (object of class "owin"
and of type "polygonal").
Adrian Baddeley Adrian.Baddeley@curtin.edu.au, Rolf Turner r.turner@auckland.ac.nz and Ege Rubak rubak@math.aau.dk
m <- as.mask(letterR, dimyx=32)
p <- as.polygonal(m)
if(interactive()) {
plot(m)
plot(p, add=TRUE, lwd=2)
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