# crossdist

0th

Percentile

##### Pairwise distances between two different point patterns

Computes the distances between pairs of points taken from two different point patterns.

Keywords
spatial
##### Usage
crossdist(X, Y, ..., method="C")
crossdist.ppp(X, Y, ..., method="C")
crossdist.default(X, Y, x2, y2, ..., method="C")
##### Arguments
X,Y
For crossdist.ppp, the arguments X and Y should be point patterns (objects of class "ppp"). For crossdist.default, the arguments X and Y should be numer
x2,y2
For crossdist.default, these should be numeric vectors of equal length specifying the location of the second point pattern.
...
Ignored by crossdist.ppp and crossdist.default.
method
String specifying which method of calculation to use. Values are "C" and "interpreted".
##### Details

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.

The function crossdist is generic, with a method for point patterns (objects of class "ppp") and a default method.

The method for point patterns expects two point patterns X and Y, and returns the matrix whose [i,j] entry is the distance from X[i] to Y[j].

The default method expects X and Y to be numeric vectors of equal length specifying the coordinates of the first point pattern. The arguments x2,y2 specify the coordinates of the second point pattern. 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.

##### Value

• A matrix whose [i,j] entry is the distance from the i-th point in the first pattern to the j-th point in the second pattern.

##### See Also

pairdist, nndist, Gest

##### Aliases
• crossdist
• crossdist.ppp
• crossdist.default
##### Examples
data(cells)
d <- crossdist(cells, runifpoint(6))

d <- crossdist(runif(7), runif(7), runif(12), runif(12))
Documentation reproduced from package spatstat, version 1.6-9, License: GPL version 2 or newer

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