connected.ppp
Connected components of a point pattern
Finds the topologically-connected components of a point pattern, when all pairs of points closer than a threshold distance are joined.
Usage
## S3 method for class 'ppp':
connected(X, R, \dots)Arguments
- X
- A point pattern (object of class
"ppp"). - R
- Threshold distance. Pairs of points closer than
Runits apart will be joined together. - ...
- Other arguments, not recognised by these methods.
Details
This function can be used to identify clumps of points in a point pattern.
The function connected is generic. This is the method for
point patterns (objects of class "ppp").
The point pattern X is first converted into an abstract graph
by joining every pair of points that lie closer than R units
apart. Then the connected components of this graph are identified.
Two points in X belong to the same connected component if they
can be reached by a series of steps between points of X,
each step being shorter than R units in length.
The result is a vector of labels for the points of X
where all the points in a connected component have the same label.
Value
- A point pattern, equivalent to
Xexcept that the points have factor-valued marks, with levels corresponding to the connected components.
See Also
Examples
Y <- connected(redwood, 0.13)
if(interactive()) {
plot(Y, cols=1:length(levels(f)))
plot(split(Y))
}