问题描述
我正在尝试将ggmap包与route()函数配合使用，以从由多对坐标组成的小动量中获取行驶距离和时间。
数据：
locations <- tibble(start_loc = c("44.025135,-69.892204","44.0175617,-70.0108097"),end_loc = "43.9195136,-69.9665309")
我想最后得到的是locations标题，并附加了另外两列：总旅行时间和总距离。为此，我可能需要遍历locations中的每一行，并通过route()函数传递每对坐标。问题在于route()的输出会为路由中的每个步骤产生一行。
到目前为止我所拥有的：
library(ggmap)
library(dplyr)
locations
# A tibble: 2 x 2
# start_loc end_loc
# <chr> <chr>
#1 44.025135,-69.892204 43.9195136,-69.9665309
#2 44.0175617,-70.0108097 43.9195136,-69.9665309
for(i in 1:nrow(locations)) {
route_output <- route(from = locations$start_loc[i],to = locations$end_loc[i],mode = c("driving"),output = c("simple"),units ="mi",structure = "legs")
}
route_output
# A tibble: 6 x 11
# m km miles seconds minutes hours start_lon start_lat end_lon end_lat route
# <int> <dbl> <dbl> <int> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <chr>
#1 2608 2.61 1.62 184 3.07 0.0511 -70.0 44.0 -70.0 44.0 A
#2 524 0.524 0.326 32 0.533 0.00889 -70.0 44.0 -70.0 44.0 A
#3 3106 3.11 1.93 232 3.87 0.0644 -70.0 44.0 -70.1 44.0 A
#4 9516 9.52 5.91 528 8.8 0.147 -70.1 44.0 -70.0 43.9 A
#5 88 0.088 0.0547 9 0.15 0.0025 -70.0 43.9 -70.0 43.9 A
#6 1960 1.96 1.22 166 2.77 0.0461 -70.0 43.9 -70.0 43.9 A
这显示的是仅最后start_loc end_loc对的路由的每一步。所以它没有像我想要的那样循环，并且我没有得到摘要信息。我什至没有办法将route_output拼凑回到“位置拼凑”。简而言之，我真的被卡住了。
关于做什么的建议？如果ggmap软件包对此不利，我还应该使用什么？
解决方法
尝试类似的东西：
library(ggmap)
locations <- data.frame(start_loc = c("44.025135,-69.892204","44.0175617,-70.0108097"),end_loc = "43.9195136,-69.9665309")
trip_dist_time <- function(from,to,mode) {
results <- ggmap::route(from,mode)
data.frame(time_minutes = sum(results$minutes),distance_km = sum(results$km),mode = mode)
}
# Select a travel mode from "driving","walking","bicycling","transit"
travel_mode <- "driving"
results <- mapply(trip_dist_time,locations$start_loc,locations$end_loc,travel_mode,SIMPLIFY = FALSE)
results <- Reduce(rbind,results)
results <- cbind(locations,results)
results
您将获得：
start_loc end_loc time_minutes distance_km mode
1 44.025135,-69.892204 43.9195136,-69.9665309 15.95 16.476 driving
2 44.0175617,-70.0108097 43.9195136,-69.9665309 19.40 17.802 driving