I was wondering whether there was a way to compare airport distances(IATA codes). There are some scripts but not is using R. So I tried that with with the API:
Example data:
library(curl) # for curl post
departure <- c("DRS","TXL","STR","DUS","LEJ","FKB","LNZ")
arrival <- c("FKB","HER","BOJ","FUE","PMI","AYT","FUE")
flyID <- c(1,2,3,4,5,6,7)
df <- data.frame(departure,arrival,flyID)
departure arrival flyID
1 DRS FKB 1
2 TXL HER 2
3 STR BOJ 3
4 DUS FUE 4
5 LEJ PMI 5
6 FKB AYT 6
7 LNZ FUE 7
api<- curl_fetch_memory("https://airport.api.aero/airport/distance/DRS/FUE?user_key=d805e84363494ca03b9b52d5a505c4d1")
cat(rawToChar(api$content))
callback({"processingDurationMillis":0,"authorisedAPI":true,"success":true,"airline":null,"errorMessage":null,"distance":"3,416.1","units":"km"})
where DRS corresponds to departure and FUE arrival airport
So I though to loop over dfand paste into url. However that seems somehow difficult for a R - Newbie
df$distance<- list(length = nrow(df))
for (i in 1:nrow(df)){
url <- paste0("https://airport.api.aero/airport/distance/", i, "FUE ?user_key=d805e84363494ca03b9b52d5a505c4d1")
myData[[i]] <- read.table(url, header=T,sep="|")
}
Desired Output:
departure arrival flyID distance
1 DRS FKB 1 1000
2 TXL HER 2 499
3 STR BOJ 3 300
4 DUS FUE 4 200
5 LEJ PMI 5 586
6 FKB AYT 6 10292
7 LNZ FUE 7 3939
Here's another way with the httr package:
library(httr)
callAPI <- function(from, to) {
res <- GET("https://airport.api.aero",
path = paste0("airport/distance/", from, "/", to),
query = list(user_key = "d805e84363494ca03b9b52d5a505c4d1"))
stop_for_status(res)
return(content(res, encoding = "UTF-8"))
}
test <- callAPI("DRS", "FKB")
# test
test$distance
# [1] "484.6"
for (i in 1:nrow(df)) {
from = df[i, "departure"]
to = df[i, "arrival"]
df[i, "distance"] <- callAPI(from, to)$distance
}
# departure arrival flyID distance
# 1 DRS FKB 1 484.6
# 2 TXL HER 2 2,131.8
# 3 STR BOJ 3 1,575.0
# 4 DUS FUE 4 3,066.3
# 5 LEJ PMI 5 1,512.4
# 6 FKB AYT 6 2,264.2
# 7 LNZ FUE 7 3,258.0
If you want to get the full results, you could use:
all_results <- mapply(function(x,y) { callAPI(x,y) }, df$departure, df$arrival)
cbind(df, t(all_results))
# departure arrival flyID processingDurationMillis authorisedAPI success airline errorMessage distance units
# 1 DRS FKB 1 0 TRUE TRUE NULL NULL 484.6 km
# 2 TXL HER 2 0 TRUE TRUE NULL NULL 2,131.8 km
# 3 STR BOJ 3 0 TRUE TRUE NULL NULL 1,575.0 km
# 4 DUS FUE 4 0 TRUE TRUE NULL NULL 3,066.3 km
# 5 LEJ PMI 5 0 TRUE TRUE NULL NULL 1,512.4 km
# 6 FKB AYT 6 0 TRUE TRUE NULL NULL 2,264.2 km
# 7 LNZ FUE 7 1 TRUE TRUE NULL NULL 3,258.0 km
You can do this without an API, just using the co-ordinates of airports, which are available freely in a database here https://raw.githubusercontent.com/jpatokal/openflights/master/data/airports.dat
## Import airport data
airports <- read.csv("https://raw.githubusercontent.com/jpatokal/openflights/master/data/airports.dat", header = F)
library(geosphere)
## Calculate matrix of differences in km
distance.matrix <- distm(x = airports[,c("V8", "V7")], y = airports[,c("V8", "V7")])/1000
## This may take a while, and will generate a matrix 8107 by 8107, about 0.5gb in size.
## Rename dimensions to airport codes
rownames(distance.matrix) <- airports$V5
colnames(distance.matrix) <- airports$V5
## Example: km between Gatwick and Heathrow
distance.matrix["LGW", "LHR"]
[1] 41.24091
What about the following loop over your api calls?
df$distance <- 0
for (i in nrow(df)){
drs <- df[i,]$departure
fue <- df[i,]$arrival
url <- paste0("https://airport.api.aero/airport/distance/", drs, "/", fue, "?user_key=4e816a2bf391f8379df1c42d2762069e")
api <- curl_fetch_memory(url)
text <- rawToChar(api$content)
distance <- as.numeric(gsub(',','',substr(text,regexpr('distance',text)+11,regexpr('units',text)-4)))
df[1,]$distance <- distance
}
df
来源：https://stackoverflow.com/questions/37572731/using-an-api-to-calculate-distance-between-two-airports-two-columns-within-r