# as.polygonal

##### 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.

##### Usage

`as.polygonal(W)`

##### Arguments

- W
- A window (object of class
`"owin"`

).

##### Details

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 already polygonal, it is returned without change.

If `W`

is a rectangle, it is converted to a polygon with
4 vertices.

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).

##### Value

- A polygonal window (object of class
`"owin"`

and of type`"polygonal"`

).

##### See Also

##### Examples

```
data(letterR)
m <- as.mask(letterR, dimyx=32)
p <- as.polygonal(m)
if(interactive()) {
plot(m)
plot(p, add=TRUE, lwd=2)
}
```

*Documentation reproduced from package spatstat, version 1.23-3, License: GPL (>= 2)*