Given a marked point pattern dataset X
this function computes, for each desired location y,
the mark attached to the nearest neighbour of y in X.
The desired locations y can be either a pixel grid
or the point pattern X itself.
nnmark(X, …, k = 1, at=c("pixels", "points"))A marked point pattern (object of class "ppp").
Arguments passed to as.mask to determine the
pixel resolution.
Single integer. The kth nearest data point will be used.
String specifying whether to compute the values
at a grid of pixel locations (at="pixels") or
only at the points of X (at="points").
If X has a single column of marks:
If at="pixels" (the default), the result is
a pixel image (object of class "im").
The value at each pixel is the mark attached
to the nearest point of X.
If at="points", the result is a vector or factor
of length equal to the number of points in X.
Entries are the mark values of the
nearest neighbours of each point of X.
If X has a data frame of marks:
If at="pixels" (the default), the result is a named list of
pixel images (object of class "im"). There is one
image for each column of marks. This list also belongs to
the class "solist", for which there is a plot method.
If at="points", the result is a data frame
with one row for each point of X,
Entries are the mark values of the
nearest neighbours of each point of X.
Given a marked point pattern dataset X
this function computes, for each desired location y,
the mark attached to the point of X that is nearest
to y. The desired locations y can be either a pixel grid
or the point pattern X itself.
The argument X must be a marked point pattern (object
of class "ppp", see ppp.object).
The marks are allowed to be a vector or a data frame.
If at="points", then for each point in X,
the algorithm finds the nearest other point in X,
and extracts the mark attached to it.
The result is a vector or data frame containing the marks
of the neighbours of each point.
If at="pixels" (the default), then for each pixel
in a rectangular grid, the algorithm finds the nearest point in X,
and extracts the mark attached to it.
The result is an image or a list of images containing the marks
of the neighbours of each pixel.
The pixel resolution is controlled by the arguments …
passed to as.mask.
If the argument k is given, then the k-th nearest
neighbour will be used.
# NOT RUN {
plot(nnmark(ants))
v <- nnmark(ants, at="points")
v[1:10]
plot(nnmark(finpines))
vf <- nnmark(finpines, at="points")
vf[1:5,]
# }
Run the code above in your browser using DataLab