In the API call, I'm setting "travelMode:google.maps.TravelMode.WALKING" - so Google is return the correct result.

So the problem is the copy I wrote. I'll leave it be since my 10-minute limit is over. But I agree I should've said "The shortest walk is x miles..."

In general, shortest would be fastest for walking (unless the difference is large and fatigue sets in).

Or you could analyse ground gradiants for steepness and find the flatest. Combine with your own personal fitness levels and solve for a better optimal route :)

> In general, shortest would be fastest for walking

Traffic lights, crime-addled regions, embassies (I wouldn't dare jog towards a guarded embassy carrying a backpack), loose gravel paths. All these will slow down walking considerably.

Or outside the city: Marshes, mountains, thick forests, muddy hill slopes.

So put the adjective "walkable" in front. The question is the same. These things are unwalkable and therefore not able to be part of any route.

Same with your car: the places without roads are undrivable and therefore not available for routing. But with a car, the speeds are so much greater than bipedal motion, shortest vs. fastest is a viable question. When the routing system avoids obstacles, it's mostly going give you the shortest and fastest route. brador makes a good point about grade; with enough grade on the shortest route, it might not be the fastest.

No, these are all walkable.

I can't believe people are actually debating this. Did you really expect a check box 'jogging with backpack' mode?

It's a quick and dirty calculation that google is making about routing. Im pretty sure the google walking routes wont take you through marshes or thick forests.