How can I calculate the distance between latitude and longitude along rows of columns in R?

Question

My df looks like this:

    bid        ts    latitude  longitude
1  827566 1999-10-07 42.40944 -88.17822
2  827566 2013-04-11 41.84740 -87.63126
3 1902966 201         


        

Answer 1

I think you're overcomplicating it a little. I wish geosphere::distHaversine had a slightly more intuitive calling method (similar to, say, diff), but it's not hard to work around it:

dat <- read.table(text = "  bid        ts    latitude  longitude
 827566 1999-10-07 42.40944 -88.17822
 827566 2013-04-11 41.84740 -87.63126
1902966 2012-05-02 45.52607 -94.20649
1902966 2013-03-25 41.94083 -87.65852
3211972 2012-08-14 43.04786 -87.96618
3211972 2013-08-02 41.88258 -87.63760", header = TRUE, stringsAsFactors = FALSE)
dat$ts <- as.Date(dat$ts)

library(dplyr)
library(geosphere)
group_by(dat, bid) %>%
  mutate(
    d = c(NA,
          distHaversine(cbind(longitude[-n()], latitude[-n()]),
                        cbind(longitude[  -1], latitude[  -1]))),
    dts = c(NA, diff(ts))
  ) %>%
  ungroup() %>%
  filter( ! is.na(d) )
# # A tibble: 3 × 6
#       bid         ts latitude longitude         d   dts
#     <int>     <date>    <dbl>     <dbl>     <dbl> <dbl>
# 1  827566 2013-04-11 41.84740 -87.63126  77159.35  4935
# 2 1902966 2013-03-25 41.94083 -87.65852 660457.41   327
# 3 3211972 2013-08-02 41.88258 -87.63760 132494.65   353