# raster.x

##### Cartesian Coordinates for a Pixel Raster

Return the $x$ and $y$ coordinates of each pixel in a binary pixel image.

##### Usage

```
raster.x(w, drop=FALSE)
raster.y(w, drop=FALSE)
raster.xy(w, drop=FALSE)
```

##### Arguments

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

) of type`"mask"`

representing a binary pixel image. - drop
- Logical.
If
`TRUE`

, then coordinates of pixels that lie outside the window are removed. If`FALSE`

(the default) then the coordinates of every pixel in the containing rectangle are retained.

##### Details

The argument `w`

should be a window (an object of class
`"owin"`

, see `owin.object`

for details).
A window of type `"mask"`

represents a binary pixel image.

If `drop=FALSE`

(the default), the
functions `raster.x`

and `raster.y`

return
a matrix of the same dimensions as the
binary pixel image itself, with entries giving the $x$ coordinate
(for `raster.x`

) or $y$ coordinate (for `raster.y`

)
of each pixel in the binary image.

If `drop=TRUE`

, pixels that lie outside the
window `w`

are removed, and `raster.x`

and `raster.y`

return numeric vectors containing the coordinates of the
pixels that are inside the window `w`

.

The function `raster.xy`

returns a list
with components `x`

and `y`

which are numeric vectors of equal length containing the pixel coordinates.

##### Value

`raster.xy`

returns a list with components`x`

and`y`

which are numeric vectors of equal length containing the pixel coordinates.If

`drop=FALSE`

,`raster.x`

and`raster.y`

return a matrix of the same dimensions as the pixel grid in`w`

, and giving the value of the $x$ (or $y$) coordinate of each pixel in the raster.If

`drop=TRUE`

,`raster.x`

and`raster.y`

return numeric vectors.

##### See Also

##### Examples

```
u <- owin(c(-1,1),c(-1,1)) # square of side 2
w <- as.mask(u, eps=0.01) # 200 x 200 grid
X <- raster.x(w)
Y <- raster.y(w)
disc <- owin(c(-1,1), c(-1,1), mask=(X^2 + Y^2 <= 1))
plot(disc)
# approximation to the unit disc
```

*Documentation reproduced from package spatstat, version 1.31-3, License: GPL (>= 2)*