| raster.x {spatstat.geom} | R Documentation |
Cartesian Coordinates for a Pixel Raster
Description
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 |
drop |
Logical.
If |
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.
Author(s)
Adrian Baddeley Adrian.Baddeley@curtin.edu.au , Rolf Turner rolfturner@posteo.net
and Ege Rubak rubak@math.aau.dk
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