# raster.x

##### Cartesian Coordinates for a Pixel Raster

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

##### Usage

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

##### Arguments

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

) or a mask window (object of class`"owin"`

of type`"mask"`

). - 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 either
a pixel image (object of class `"im"`

)
or a mask window (an object of class
`"owin"`

of type `"mask"`

).

If `drop=FALSE`

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

and `raster.y`

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

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

)
of each pixel in the pixel grid.

If `drop=TRUE`

, pixels that lie outside the
window `w`

(or outside the domain of the image `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 1.41-1, License: GPL (>= 2)*