计算数据框中两个长纬度坐标之间的距离

Question

I want to calculate the distance between several GPS points. I tried

distm(c(lon1,lat1), c(lon2,lat2), fun = distHaversine)

which worked for one point, but not for the columns in my data frame.

So I tried as recommended here:

Calculate distance between 2 lat longs

But I do get different results for these two calculations:

df <- read.table(sep=",", col.names=c("lat1", "lon1", "lat2", "lon2"),text="
7.348687,53.36575,7.348940,53.36507 
7.348940, 53.36507,7.350939,53.36484")


# as recommended in the link above
distHaversine(df[,2:1], df[,4:3])

[1]  80.18433 223.97181

# with distm
distm(c(7.348687,53.36575), c(7.348940,53.36507), fun = distHaversine)

         [,1]
[1,] 77.54033

distm(c(7.348940, 53.36507), c(7.350939,53.36484), fun = distHaversine)

         [,1]
 [1,] 135.2317

So how can I calculate the correct distances (which is distm(c(lon1,lat1), c(lon2,lat2), fun = distHaversine)) between two GPS points in the columns of my data frame? I double-checked with so distances that I know I get the right distances this way.

Thanks in advance.

Answer 1

Given that the output you want to store in the new column is this:

77.54033 135.23165

Try this

df$distance<-distHaversine(df[,1:2], df[,3:4])

Which should return

> df
      lat1     lon1     lat2     lon2  distance
1 7.348687 53.36575 7.348940 53.36507  77.54033
2 7.348940 53.36507 7.350939 53.36484 135.23165

Answer 2

What exactly is the question? Don't you already have all the distances you need with distHaversine() ?

Do you want to add the distance as column in the dataframe? Here you go:

f$dist <- distm(x = df[, c('lon1', 'lat1')], 
                y = df[, c('lon2', 'lat2')],
                fun = distHaversine
                )

Answer 3

I found another solution for the problem

for (i in 1:2) {

  a<-df$lon1[i]
  b<-df$lat1[i]
  c<-df$lon2[i]
  d<-df$lat2[i]

  df$distance[i]<-distm(c(a,b),c(c,d), fun = distHaversine)
  }

write.xlsx(df, file = "C:/Users/distances.xlsx")