Let’s walk through why you’re seeing that NOT FOUND error and fix your function to get reliable travel duration data:

1. The Immediate Fix: Complete Your API Request URL #

Looking at your code snippet, the strQuery string gets cut off mid-destination parameter (destinat...). The Google Maps Directions API requires a full, properly formatted URL with all mandatory parameters to process your request—an incomplete URL will almost always throw a NOT FOUND error.

2. Full Corrected Function #

I’ve updated your code to fix the URL structure, add proper error handling, and extract the duration data you need. Here’s the polished version:

getDuration <- function(from, to, tMode, key){ 
  # Convert to UTF-8 and URL-encode parameters to handle special characters
  from <- URLencode(iconv(from, to="UTF-8"))
  to <- URLencode(iconv(to, to="UTF-8"))
  tMode <- URLencode(iconv(tMode, to="UTF-8"))
  
  # Build the complete, valid API request URL
  strQuery <- paste0(
    "https://maps.googleapis.com/maps/api/directions/json?",
    "origin=", from,
    "&destination=", to,
    "&mode=", tMode,
    "&key=", key
  )
  
  # Send the request and check for HTTP-level errors
  library(httr)
  response <- GET(strQuery)
  if (http_status(response)$category != "Success") {
    stop("Request failed: ", http_status(response)$message)
  }
  
  # Parse the JSON response from the API
  result <- content(response, as = "parsed")
  
  # Check for API-specific errors (e.g., invalid key, missing permissions)
  if (result$status != "OK") {
    stop("API Error: ", result$status, " - ", result$error_message)
  }
  
  # Extract duration data (uses the first route/leg; adjust if you need alternatives)
  duration_text <- result$routes[[1]]$legs[[1]]$duration$text
  duration_seconds <- result$routes[[1]]$legs[[1]]$duration$value
  
  return(list(duration = duration_text, duration_seconds = duration_seconds))
}

3. Additional Troubleshooting Steps #

If you still run into issues after fixing the URL, check these common culprits:

• API Key Permissions: Make sure your Google Cloud API key has the Directions API enabled, and there are no IP/usage restrictions blocking your request.
• Valid Travel Mode: Ensure tMode is one of the allowed values: driving, walking, bicycling, or transit—using an invalid mode will trigger errors.
• Test the URL Manually: Print out the strQuery value and paste it into a browser. The raw API response will show you exact error details (like invalid origin/destination) that might not surface in your R code at first.

内容的提问来源于stack exchange，提问作者Grigory Sharkov