Pairwise distances between two different point patterns
Computes the distances between pairs of points taken from two different point patterns.
## S3 method for class 'ppp' crossdist(X, Y, ..., periodic=FALSE, method="C", squared=FALSE)
X,Y |
Point patterns (objects of class |
... |
Ignored. |
periodic |
Logical. Specifies whether to apply a periodic edge correction. |
method |
String specifying which method of calculation to use.
Values are |
squared |
Logical. If |
Given two point patterns, this function computes the Euclidean distance from each point in the first pattern to each point in the second pattern, and returns a matrix containing these distances.
This is a method for the generic function crossdist
for point patterns (objects of class "ppp").
This function expects two
point patterns X and Y, and returns the matrix
whose [i,j] entry is the distance from X[i] to
Y[j].
Alternatively if periodic=TRUE, then provided the windows
containing X and Y are identical and are rectangular,
then the distances will be computed in the ‘periodic’
sense (also known as ‘torus’ distance): opposite edges of the
rectangle are regarded as equivalent.
This is meaningless if the window is not a rectangle.
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 a factor of 4.
A matrix whose [i,j] entry is the distance
from the i-th point in X
to the j-th point in Y.
Pavel Grabarnik pavel.grabar@issp.serpukhov.su and Adrian Baddeley Adrian.Baddeley@curtin.edu.au
Y <- runifrect(6, Window(cells)) d <- crossdist(cells, Y) d <- crossdist(cells, Y, periodic=TRUE)
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