Hi
I am trying to create a list of nearest neighbors using knearneigh and
dinearneigh. To understand these I have been coding what these functions do:
For example, for dnearneigh, suppose I have x-y coordinates and the
corresponding z values
# calculate distances between observations
data<-cbind(x,y,z)
coords<-cbind(x,y)
dis<-as.matrix(dist(coords,diag=T,upper=T))
# Create distance threshold =2
thrs<-2
nb<-list(vector("numeric",length(z)))
for (j in 1:nrow(data)){
nb[[j]]<-as.vector(which(dis[j,]<=thrs))
}
nb
Then I can use this nb list to compute many local statistics.
For knearneigh, I can sort the distance matrix in ascending order and
take the first n numbers as nearest neighbors. Then, how can I take a
look at a list of neighbors when I use knearneigh? unlist(nb,coords)
just breaks the [[ ]] structure...
Thank for help in advance.
Taka
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