For example, lets say I have two parallel roads with starting point and ending point 1 mile apart.
The left hand road is as flat and straight as an arrow.
The right hand road is also straight....but has a series of sine-wave shaped hills and valleys.
Obviously, if I measure using a Surveyor's wheel, the second path will be longer, even though both roads are starting and ending a mile apart.
My question: which measurement does google maps use? Does it account for difference in elevation adding to the travel distance?