nndist(X, ..., method="C")
nndist.ppp(X, ..., method="C")
nndist.default(X, Y=NULL, ..., method="C")
nndist.ppp
, the argument X
should be a point
pattern (object of class "ppp"
).
For nndist.default
, typically X
and <nndist.ppp
and nndist.default
."C"
and "interpreted"
. The function nndist
is generic, with
a method for point patterns (objects of class "ppp"
)
and a default method.
The method for point patterns expects a single
point pattern argument X
and returns the vector of its
nearest neighbour distances.
The default method expects that X
and Y
will determine
the coordinates of a set of points. Typically X
and
Y
would be numeric vectors of equal length. Alternatively
Y
may be omitted and X
may be a list with two components
named x
and y
, or a matrix or data frame with two columns.
The argument method
is not normally used. It is
retained only for checking the validity of the software.
If method = "interpreted"
then the distances are
computed using interpreted R code only. If method="C"
(the default) then C code is used.
The C code is faster by two to three orders of magnitude
and uses much less memory.
If there is only one point (if x
has length 1),
then a nearest neighbour distance of Inf
is returned.
If there are no points (if x
has length zero)
a numeric vector of length zero is returned.
pairdist
,
Gest
data(cells)
d <- nndist(cells)
x <- runif(100)
y <- runif(100)
d <- nndist(x, y)
# Stienen diagram
plot(cells %mark% (nndist(cells)/2), markscale=1)
Run the code above in your browser using DataLab