quadrats
Divide Region into Quadrats
Divides window into rectangular quadrats and returns the quadrats as a tessellation.
Usage
quadrats(X, nx = 5, ny = nx, xbreaks = NULL, ybreaks = NULL)Arguments
- X
- A window (object of class
"owin") or anything that can be coerced to a window usingas.owin, such as a point pattern. - nx,ny
- Numbers of quadrats in the $x$ and $y$ directions.
Incompatible with
xbreaksandybreaks. - xbreaks
- Numeric vector giving the $x$ coordinates of the
boundaries of the quadrats. Incompatible with
nx. - ybreaks
- Numeric vector giving the $y$ coordinates of the
boundaries of the quadrats. Incompatible with
ny.
Details
If the window X is a rectangle, it is divided into
an nx * ny grid of rectangular tiles or `quadrats'.
If X is not a rectangle, then the bounding rectangle of
X is first divided into an nx * ny grid of rectangular
tiles, and these tiles are then intersected with the window X.
The resulting tiles are returned as a tessellation (object of class
"tess") which can be plotted and used in other analyses.
If xbreaks is given, it should be a numeric vector
giving the $x$ coordinates of the quadrat boundaries.
If it is not given, it defaults to a
sequence of nx+1 values equally spaced
over the range of $x$ coordinates in the window X$window.
Similarly if ybreaks is given, it should be a numeric
vector giving the $y$ coordinates of the quadrat boundaries.
It defaults to a vector of ny+1 values
equally spaced over the range of $y$ coordinates in the window.
The lengths of xbreaks and ybreaks may be different.
Value
- A tessellation (object of class
"tess") as described undertess.
See Also
Examples
W <- square(10)
Z <- quadrats(W, 4, 5)
plot(Z)
data(letterR)
plot(quadrats(letterR, 5, 7))