Last chance! 50% off unlimited learning
Sale ends in
A simple class of functions of spatial location
funxy(f, W)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.
A function in the R language
with arguments x,y (at least)
Window (object of class "owin") inside which the
function is well-defined.
Adrian Baddeley Adrian.Baddeley@curtin.edu.au, Rolf Turner r.turner@auckland.ac.nz and Ege Rubak rubak@math.aau.dk.
This command creates an object of class "funxy".
This is a simple mechanism for handling a function
of spatial location
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.
The result also has a unitname, inherited from W.
plot.funxy,
summary.funxy
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])
Run the code above in your browser using DataLab