Spatial Function Class
A simple class of functions of spatial location
funxy(f, W)
f |
A |
W |
Window (object of class |
This creates an object of class "funxy".
This is a simple mechanism for handling a function
of spatial location f(x,y) to make it easier to display
and manipulate.
f should be a function in the R language.
The first two arguments of f must be named x and y
respectively.
W should be a window (object of class "owin") inside which the
function f is well-defined.
The function f should be vectorised: that is,
if x and y are numeric vectors of the same length
n, then v <- f(x,y) should be a vector of length
n.
The resulting function g <- funxy(f, W) has the same formal
arguments as f and can be called in the same way,
v <- g(x,y) where x and y are numeric vectors.
However it can also be called as v <- g(X), where X is a point pattern
(object of class "ppp" or "lpp")
or a quadrature scheme (class "quad");
the function will be evaluated at the points of X.
A function with the same arguments as f,
which also belongs to the class "funxy".
This class has methods for
print, plot, contour and persp.
Adrian Baddeley Adrian.Baddeley@curtin.edu.au, Rolf Turner r.turner@auckland.ac.nz and Ege Rubak rubak@math.aau.dk.
f <- function(x,y) { x^2 + y^2 - 1}
g <- funxy(f, square(2))
g
## evaluate function at any x, y coordinates
g(0.2, 0.3)
## evaluate function at the points of a point pattern
g(cells[1:4])Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.