按行计算点和线之间的距离

Question

我想计算数据集每行中显示的点和线之间的距离。 下面是我拥有的数据的一个小例子

  point_id point_lat point_lon                       geometry line_id
1    25417   47.2085   6.23435 LINESTRING (5.71922 47.01, ...    1203
2    21475   47.0499   5.21145 LINESTRING (5.13693 46.9399...    1120

dput(data)

structure(list(point_id = c("25417", "21475"), point_lat = c(47.2084948390554, 
47.049888920732), point_lon = c(6.23434636370335, 5.21144989212184
), geometry = structure(list(structure(c(5.7192239291661, 5.72408115442851, 
47.0100084570507, 47.0055943850847), .Dim = c(2L, 2L), class = c("XY", 
"LINESTRING", "sfg")), structure(c(5.13693475951681, 5.14588443111801, 
46.9399237940937, 46.9393947420422), .Dim = c(2L, 2L), class = c("XY", 
"LINESTRING", "sfg"))), class = c("sfc_LINESTRING", "sfc"), precision = 0, bbox = structure(c(xmin = 5.13693475951681, 
ymin = 46.9393947420422, xmax = 5.72408115442851, ymax = 47.0100084570507
), class = "bbox"), crs = structure(list(input = "EPSG:4326", 
    wkt = "GEOGCRS[\"WGS 84\",\n    ENSEMBLE[\"World Geodetic System 1984 ensemble\",\n        MEMBER[\"World Geodetic System 1984 (Transit)\"],\n        MEMBER[\"World Geodetic System 1984 (G730)\"],\n        MEMBER[\"World Geodetic System 1984 (G873)\"],\n        MEMBER[\"World Geodetic System 1984 (G1150)\"],\n        MEMBER[\"World Geodetic System 1984 (G1674)\"],\n        MEMBER[\"World Geodetic System 1984 (G1762)\"],\n        MEMBER[\"World Geodetic System 1984 (G2139)\"],\n        ELLIPSOID[\"WGS 84\",6378137,298.257223563,\n            LENGTHUNIT[\"metre\",1]],\n        ENSEMBLEACCURACY[2.0]],\n    PRIMEM[\"Greenwich\",0,\n        ANGLEUNIT[\"degree\",0.0174532925199433]],\n    CS[ellipsoidal,2],\n        AXIS[\"geodetic latitude (Lat)\",north,\n            ORDER[1],\n            ANGLEUNIT[\"degree\",0.0174532925199433]],\n        AXIS[\"geodetic longitude (Lon)\",east,\n            ORDER[2],\n            ANGLEUNIT[\"degree\",0.0174532925199433]],\n    USAGE[\n        SCOPE[\"Horizontal component of 3D system.\"],\n        AREA[\"World.\"],\n        BBOX[-90,-180,90,180]],\n    ID[\"EPSG\",4326]]"), class = "crs"), n_empty = 0L), 
    line_id = c(1203L, 1120L)), row.names = c(NA, -2L), class = "data.frame")

我想计算对应线的点之间的距离。所以点 25417 和线 1203 之间的距离以及 21475 和线 1120 之间的距离。

谢谢您的帮助

Answer 1

这是一个有点不常见的结构，因为它带有

geometry

/ sfc 列，但

sf

类属性未设置或被有意删除（即

sf

方法不能在框架本身上使用）

我们可以采用这样的方法，同时保持结果为

data.frame

:

• 从点坐标生成

  sf

  点对象，假设坐标为WGS84（

  y

  参数）
• 查找

  geometry

  列（

  x

  参数）中的行与生成的

  sf

  对象 (

  y

  )
之间的元素距离

library(sf)
data$dist_m <- st_distance(x = data$geometry, 
                           y = st_as_sf(data, coords = c("point_lon", "point_lat"), crs = "WGS84"),
                           by_element = TRUE)
data
#>   point_id point_lat point_lon                       geometry line_id
#> 1    25417  47.20849  6.234346 LINESTRING (5.719224 47.010...    1203
#> 2    21475  47.04989  5.211450 LINESTRING (5.136935 46.939...    1120
#>         dist_m
#> 1 44725.65 [m]
#> 2 13254.55 [m]

^{创建于 2023-09-28，使用 reprex v2.0.2}