knearneigh(spdep)
knearneigh()所属R语言包:spdep
K nearest neighbours for spatial weights
K近邻的空间权重
译者:生物统计家园网 机器人LoveR
描述----------Description----------
The function returns a matrix with the indices of regions belonging to the set of the k nearest neighbours of each other. If longlat = TRUE, Great Circle distances are used.
该函数返回一个矩阵的指数集的k近邻,彼此的区域属于。如果longlat = TRUE,大圆距离使用。
用法----------Usage----------
knearneigh(x, k=1, longlat = NULL, RANN=TRUE)
参数----------Arguments----------
参数:x
matrix of region point coordinates or a SpatialPoints object
区域点的坐标矩阵或SpatialPoints对象
参数:k
number of nearest neighbours to be returned
一些最近的邻居将返回
参数:longlat
TRUE if point coordinates are longitude-latitude decimal degrees, in which case distances are measured in kilometers; if x is a SpatialPoints object, the value is taken from the object itself
TRUE,如果点坐标的经纬度小数度,在这种情况下,测量距离(公里),如果x是一个SpatialPoints,对象,对象本身的价值是从
参数:RANN
logical value, if the RANN package is available, use for finding k nearest neighbours when longlat is FALSE
逻辑值,如果兰恩包,使用时发现k近邻longlat是FALSE
Details
详细信息----------Details----------
The underlying C code is based on the knn function in the class package in the VR bundle.
底层的C代码是基于knn功能在VR包中的类包。
值----------Value----------
A list of class knn
列表类knn
参数:nn
integer matrix of region number ids
整数矩阵的区域编号IDS
参数:np
number of input points
输入点的数
参数:k
input required k
输入所需K表
参数:dimension
number of columns of x
的x的列数
参数:x
input coordinates
输入坐标
(作者)----------Author(s)----------
Roger Bivand <a href="mailto:Roger.Bivand@nhh.no">Roger.Bivand@nhh.no</a>
参见----------See Also----------
knn, dnearneigh,
knn,dnearneigh,
实例----------Examples----------
example(columbus)
coords <- coordinates(columbus)
col.knn <- knearneigh(coords, k=4)
plot(columbus, border="grey")
plot(knn2nb(col.knn), coords, add=TRUE)
title(main="K nearest neighbours, k = 4")
data(state)
us48.fipsno <- read.geoda(system.file("etc/weights/us48.txt",
package="spdep")[1])
if (as.numeric(paste(version$major, version$minor, sep="")) < 19) {
m50.48 <- match(us48.fipsno$"State.name", state.name)
} else {
m50.48 <- match(us48.fipsno$"State_name", state.name)
}
xy <- as.matrix(as.data.frame(state.center))[m50.48,]
llk4.nb <- knn2nb(knearneigh(xy, k=4, longlat=FALSE))
gck4.nb <- knn2nb(knearneigh(xy, k=4, longlat=TRUE))
plot(llk4.nb, xy)
plot(diffnb(llk4.nb, gck4.nb), xy, add=TRUE, col="red", lty=2)
title(main="Differences between Euclidean and Great Circle k=4 neighbours")
summary(llk4.nb, xy, longlat=TRUE)
summary(gck4.nb, xy, longlat=TRUE)
xy1 <- SpatialPoints((as.data.frame(state.center))[m50.48,],
proj4string=CRS("+proj=longlat"))
gck4a.nb <- knn2nb(knearneigh(xy1, k=4))
summary(gck4a.nb, xy1)
转载请注明:出自 生物统计家园网(http://www.biostatistic.net)。
注:
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