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rgeospatialdistancelatitude-longitudegeosphere

Trying to find the distance between pairs of latitude and longitude coordinates

Currently have a data frame of 4 columns, "lon.x," "lat.x," "lon.y," "lat.y." with 581 rows. I would like to find the distance between each pair of coordinates.

I tried:

library(geosphere)
distm(c(coords$lon_x, coords$lat_x),c(coords$lon_y, coords$lat_y), fun = distHaversine())

But got this error

Error in .pointsToMatrix(x) : Wrong length for a vector, should be 2

Is there a different way to do this?

Solution

  • Using distm(cbind(coords$lon_x, coords$lat_x), cbind(coords$lon_y, coords$lat_y), distHaversine) or distm(coords[, c("lon_x", "lat_x")], coords[, c("lon_y", "lat_y")], distHaversine) works for me, or even more succinct using with:

    library(geosphere)
res <- with(coords, distm(cbind(lon_x, lat_x), cbind(lon_y, lat_y), distHaversine))
res
#           [,1]     [,2]     [,3]     [,4]      [,5]
# [1,]  82926.65 102777.0 416520.9 317338.5 229201.72
# [2,] 227148.47 371663.8 472784.4 441059.9  51871.09
# [3,] 131700.50 212885.3 344615.2 270580.8 166672.80
# [4,] 170629.69 314137.0 566038.0 506409.5 114399.77
# [5,] 125941.89 208759.0 350108.9 275223.3 164881.02

    You just want the diag, though.

    diag(res)
# [1]  82926.65 371663.76 344615.24 506409.47 164881.02

    Check:

    with(coords, distm(cbind(lon_x, lat_x)[1,], cbind(lon_y, lat_y)[1,], distHaversine))
#          [,1]
# [1,] 82926.65
with(coords, distm(cbind(lon_x, lat_x)[2,], cbind(lon_y, lat_y)[2,], distHaversine))
#          [,1]
# [1,] 371663.8
with(coords, distm(cbind(lon_x, lat_x)[3,], cbind(lon_y, lat_y)[3,], distHaversine))
#          [,1]
# [1,] 344615.2

    Toy data:

    n <- 5
set.seed(42)
coords <- data.frame(id=seq(n), 
                     lon_x=rnorm(n, 47.364842), lat_x=rnorm(n, 8.573026),
                     lon_y=rnorm(n, 47.364842), lat_y=rnorm(n, 8.573026),
                     sth_else=rnorm(n))