# distmap.owin

##### Distance Map of Window

Computes the distance from each pixel to the nearest point in the given window.

- Keywords
- spatial

##### Usage

`distmap.owin(X, ...)`

##### Arguments

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

). - ...
- Arguments passed to
`as.mask`

to control pixel resolution.

##### Details

The ``distance map'' of a window $W$ is the function
$f$ whose value `f(u)`

is defined for any two-dimensional
location $u$ as the shortest distance from $u$ to $W$.

This function computes the distance map of the window `X`

and returns the distance map as a pixel image. The greyscale value
at a pixel $u$ equals the distance from $u$ to the nearest
pixel in `X`

.

Additionally, the return value
has an attribute `"bdry"`

which is
also a pixel image. The grey values in `"bdry"`

give the
distance from each pixel to the bounding rectangle of the image.

If the window `X`

is not already a pixellated window
(a binary image mask), it is converted into one. The arguments
`...`

control the pixel resolution in this case, but will
otherwise be ignored.
This function is a method for the generic `distmap`

.

##### Value

- A pixel image (object of class
`"im"`

) whose greyscale values are the values of the distance map. The return value has an attribute`"bdry"`

which is a pixel image.

##### See Also

##### Examples

```
data(letterR)
U <- distmap(letterR)
plot(U)
plot(attr(U, "bdry"))
```

*Documentation reproduced from package spatstat, version 1.5-5, License: GPL version 2 or newer*