Let's try to find directions in Google Maps from, for example from:
- Pamplona (Spain) to
- Burgos (Spain)
And now, let's try the other way:
- Burgos (Spain) to
- Pamplona (Spain)
You'll see that Google Maps returns a different set of routes depending on which sense you go. And it does the same, I should say, when querying it through the Directions API in Javascript.
Why does it do that? What criteria does Google Maps use to decide which route to use or discard in each case? (I have some intuitions about it, but I'd like to know for sure, since we are developing an app that relies in part on the Directions API).