使用mutate中的distm函数计算两点之间的距离 [英] Calculating distance between two points using the distm function inside mutate

问题描述

我正在尝试计算两组经度和纬度坐标之间的距离.

I am trying to calculate the distance between two sets of longitude and latitude coordinates.

我正在使用封装地理层中的distm()函数来完成此操作.

I am using the function distm() from the package geosphere to do this.

如果我手动在distm()函数中输入值，效果很好，但是我无法在mutate命令中使用它.

It works fine if I manually put in the values in the distm() function, but I can't get it to work inside my mutate command.

在mutate函数中运行它时，出现错误:

When running it inside a mutate function I get the error:

Error in mutate_impl(.data, dots) : 
Evaluation error: Wrong length for a vector, should be 2.

@Dotpi在评论中写道小注释.未对geosphere:distm方法进行矢量化.要对其进行矢量化，请使用apply函数." 在此线程中回答(用于计算两点之间的地理空间距离(纬度，经度)，使用R )

@Dotpi wrote in a comment "A small note. The method geosphere:distm is not vectorized. To vectorize it use the apply functions." when he replied in this thread (Function to calculate geospatial distance between two points (lat,long) using R)

据此，我猜测这是导致mutate函数错误的原因，但我不知道如何解决.我希望使用tidyverse解决方案，但会有所帮助.

From that I am guessing that this is what is causing the error in the mutate function, but I don't know how to solve it. I would prefer a tidyverse solution, but any help is appreciated.

下面是一个测试数据帧，其中首先包含产生错误的代码，然后是一个工作示例，在该示例中，我手动从DF的第一行插入了值.

Below is a test dataframe with first the code that produces the error, and then a working example where I manually insert the values from the first row in DF.

library(tidyverse)
library(geosphere)

set.seed(1)
DF <- tibble(
  Long1 = sample(1:10),
  Lat1 = sample(1:10),
  Long2 = sample(1:10),
  Lat2 = sample(1:10))

DF %>% mutate(
  Dist = distm(x= c(Long1, Lat1), y=c(Long2, Lat2), fun = distHaversine ))

distm( x = c(3, 3), y = c(10, 5), fun = distHaversine )

推荐答案

也许我们可以使用 pmap

library(purrr)
pmap_dbl(DF, ~ distm(x = c(..1, ..2), y = c(..3, ..4), 
                    fun = distHaversine) %>% c)

与 mutate

library(dplyr)
DF %>% 
  mutate(Dist = pmap_dbl(., ~
           distm(x = c(..1, ..2), y = c(..3, ..4), fun = distHaversine)))
# A tibble: 10 x 5
#   Long1  Lat1 Long2  Lat2     Dist
#   <int> <int> <int> <int>    <dbl>
# 1     3     3    10     5  808552.
# 2     4     2     2     6  497573.
# 3     5     6     6     4  248726.
# 4     7    10     1     2 1110668.
# 5     2     5     9    10  951974.
# 6     8     7     8     8  111319.
# 7     9     8     7     9  246730.
# 8     6     4     5     1  351986.
# 9    10     1     3     7 1024599.
#10     1     9     4     3  745867.

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