I am working on a service where a user plans his route using the Google Direction Service. GDS returns (if available) alternatives and the users can choose one of these for later usage. This part works: I know how to do the first request including getting alternatives back.
My problem is: how do I rerequest that specific alternative. For instance: if I want to redisplay the route and send the request to Google, it serves me the three alternatives... But I want to show the chosen one. I thought GDS would give the discriminating waypoints it uses to make the alternative, but it doesn't. As far as I see there is nothing discriminating, but I'd like to hear your thoughts on this. A different approach would be to either remember the summary or the route index or both. I would then use one of those (or both) to select the alternative from the set. But this is only possible if the summary and/or the index does not change. And it is a bit of a cumbersome way. Another approach is to try to find the discriminating waypoints ourselves, but this seems too hard to handle...
Any thougts on this are welcomed!
Frank