About 90% of the time, when using get_map in ggmap, I get the following error. Can someone please tell me why?
map <- get_map(location = 'Australia', zoom = 4)
Error in download.file(url, destfile = destfile, quiet = !messaging, mode = "wb") : cannot open URL 'http://maps.googleapis.com/maps/api/staticmap?center=Australia&zoom=4&size=%20640x640&scale=%202&maptype=terrain&sensor=false' In addition: Warning message: In download.file(url, destfile = destfile, quiet = !messaging, mode = "wb") : cannot open: HTTP status was '403 Forbidden'
The problem is likely related to your API project not being authorized by Google.
An API project is easy to create, and get authorized:
Click this link and choose create. Alternatively choose select if you already have a created project, but just need to activate the API.
After that choose "Enable".
After that your code should work.
Link again: https://console.developers.google.com/apis/api/static_maps_backend?project=_
The 403 error is because Google now requires users to register for and use a (free) api key.
The "zoom = 4" is, per documentation, "reserved for google business users only." I can't find much documented on why this would work intermittently or at all for a non-business user, but that's my best guess.
来源：https://stackoverflow.com/questions/19827598/error-in-get-map-using-ggmap-in-r