Question

给定具有纬度和经度的数据帧，我想添加一个列，该列仅包含在某个半径范围内的其他点（相同数据帧）的计数，例如距离该特定点10公里。

示例数据：

set.seed(1)
radius<-10
lat<-runif(10,-90,90)
long<-runif(10,-180,180)
id<-1:10
dat<-cbind(id,lat,long)

      id       lat         long
 [1,]  1 -42.20844 -105.8491530
 [2,]  2 -23.01770 -116.4395691
 [3,]  3  13.11361   67.3282248
 [4,]  4  73.47740  -41.7226614
 [5,]  5 -53.69725   97.1429112
 [6,]  6  71.71014   -0.8282728
 [7,]  7  80.04155   78.3426630
 [8,]  8  28.94360  177.0861941
 [9,]  9  23.24053  -43.1873354
[10,] 10 -78.87847   99.8802797

现在给定半径变量我想要一个新列说＆＃34; X＆＃34;对于每个点，仅包含＆＃34;半径＆＃34;内的其他点的数量。我不关心这些是什么点。

虽然此R - Finding closest neighboring point and number of neighbors within a given radius, coordinates lat-long主题和答案已接近，但它并未解决简单计数的具体问题。这个问题不同，因为我需要半径内所有点的计数而不是点

Answer 1

试试这个：

library(geosphere)
cbind(dat, X=rowSums(distm (dat[,3:2], 
       fun = distHaversine) / 1000 <= 10000)) # number of points within distance 10000 km

      id       lat         long X
 [1,]  1 -42.20844 -105.8491530 5
 [2,]  2 -23.01770 -116.4395691 5
 [3,]  3  13.11361   67.3282248 5
 [4,]  4  73.47740  -41.7226614 6
 [5,]  5 -53.69725   97.1429112 4
 [6,]  6  71.71014   -0.8282728 6
 [7,]  7  80.04155   78.3426630 6
 [8,]  8  28.94360  177.0861941 5
 [9,]  9  23.24053  -43.1873354 6
[10,] 10 -78.87847   99.8802797 4

计算某个半径内的点数

1 个答案: