我试图计算r中一系列GPS点的最近邻点之间的平均距离。我找到了两个代码来获取值。但它似乎没有给出正确的米距离。当我在谷歌地图上查看时,它完全不在状态。
我找到了这个答案:R-找到给定半径内最近的相邻点和相邻点的数量,坐标为lat long
library(geosphere)
sp.groups <- groups
coordinates(sp.groups) <- ~Long+Lat
class(sp.groups)
d<- distm(sp.groups)
min.d<- apply(d, 1, function(x) order(x, decreasing=F)[2])
min.d
mean(min.d)
groupdist<- cbind(groups, groups[min.d,], apply(d, 1, function(x) order(x, decreasing=F)[2]))
colnames(groupdist)<- c(colnames(groups), 'neighbor', 'n.lat', 'n.long','dist')
这里使用包 rgeos,但它给出相同的结果: 计算两个数据集(最近邻)两点之间的距离
library(rgeos)
sp.groups <- groups
coordinates(sp.groups) <- ~Long+Lat
proj4string(sp.groups) <-CRS("+proj=utm +datum=WGS84")
class(sp.groups)
d<- gDistance(sp.groups, byid=TRUE)
min.d<- apply(d, 1, function(x) order(x, decreasing=F)[2])
min.d
mean(min.d)
groupdist<- cbind(groups, groups[min.d,], apply(d, 1, function(x) order(x, decreasing=F)[2]))
colnames(groupdist)<- c(colnames(groups), 'neighbor', 'n.lat', 'n.long','dist')
当我去谷歌地球(Google Earth)上查看时,距离可能相差很远。它甚至为160-200米的最近邻居提供了不同的值。此外,一些最近的邻居的距离值也不相同,请参见K11和K3,然后是K3和K11。以下是我得到的结果,我从谷歌地图中添加了预期值:
Group Lat Long neighbor n.lat n.long dist GMaps
K1 -26.96538 21.80965 K34 -26.96503 21.80940 27 44
K10 -26.96575 21.81132 K1 -26.96538 21.80965 1 172
K11 -26.96249 21.81120 K3 -26.96387 21.81053 22 166
K24 -26.96033 21.81090 K11 -26.96249 21.81120 3 240
K3 -26.96387 21.81053 K11 -26.96249 21.81120 3 166
K34 -26.96503 21.80940 K1 -26.96538 21.80965 1 44
怎么了?
我的数据
groups<-data.frame(Group = c('K1', 'K10', 'K11', 'K24', 'K3', 'K34'),
Lat = c(-26.96538, -26.96575, -26.96249, -26.96033, -26.96387, -25.96503),
Longitude = c(21.80965, 21.81132, 21.81120, 21.80190, 21.81053, 21.80940))
我不知道你在这里试图计算什么,但列距离
只是指具有最小距离的点的位置/数字。我添加了一个具有实际最小距离的数字,看起来像你期望的结果。
library(geodist, include.only = NULL)
library(sp, include.only = NULL)
groups <- data.frame(Group = c('K1', 'K10', 'K11', 'K24', 'K3', 'K34'),
Lat = c(-26.96538, -26.96575, -26.96249, -26.96033, -26.96387, -25.96503),
Long = c(21.80965, 21.81132, 21.81120, 21.80190, 21.81053, 21.80940))
sp.groups <- groups
sp::coordinates(sp.groups) <- ~Long+Lat
# mindistance Matrix
d <- geodist::geodist(groups, measure = "cheap")
# position of minimum distance
diag(d) <- Inf
min.d <- max.col(-d)
min.d
#> [1] 2 1 5 5 3 4
groupdist <- cbind(groups, groups[min.d,], min.d)
colnames(groupdist) <- c(colnames(groups), 'neighbor', 'n.lat', 'n.long','closest_to')
# get minimum distance for each pair of coordinates
groupdist$distance <- d[cbind(seq_along(min.d), min.d)]
groupdist
#> Group Lat Long neighbor n.lat n.long closest_to distance
#> 2 K1 -26.96538 21.80965 K10 -26.96575 21.81132 2 171.1554
#> 1 K10 -26.96575 21.81132 K1 -26.96538 21.80965 1 171.1554
#> 5 K11 -26.96249 21.81120 K3 -26.96387 21.81053 5 167.2225
#> 5.1 K24 -26.96033 21.80190 K3 -26.96387 21.81053 5 944.4119
#> 3 K3 -26.96387 21.81053 K11 -26.96249 21.81120 3 167.2225
#> 4 K34 -25.96503 21.80940 K24 -26.96033 21.80190 4 110613.1362
由reprex包(v2.0.1)于2021-08-22创建