I've have just about googled the hell out of this topic, but is it at all possible to import a gmaps map into a navigation app on a smartphone and have it give you turn-by-turn directions? It seems like a simple thing, but for some reason it just doesn't seem like anyone has done it...
Is there a way of doing this?
I've experimented with this a bit myself. The short answer is, there's not really a great way to do it.
The problem is that the routes you create in gmap-pedometer don't necessarily line up with the course of roads created in the real world. When you get turn-by turn directions from a GPS app or device, that route you're traveling was accompanied by metadata about the names of roads, the places they intersect, the degrees of the intersections, and many other points.
Although some routes in the site have this sort of data as well, not all do. They way this site works, you may have one route that has some portions generated from google's routing, and some that were drawn by the user.
The experiment I tried was imoporting a route I'd created into a third-party app. Since the route went in without any of that metadata I mentioned, it was trying to literally provide turn by turn directions every time a road bent at all. When you create a route on a road that curves, it actually creates many many short straight lines. Now imagine getting directions to turn 2 degrees to the left every few feet. Didn't work great :(
I have had one idea that I find works on a bike. There are apps that let you superimpose a line from my site on a map. I set my phone up on a holder on my handlebars, and was able to make sure I was on course as I biked a route. I don't think that would be all that great for runners, but it worked ok on the bike. What do you think of that?