# Does google maps use elevation to calculate travel distance?

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?

• Your difference there is a difference in road length, not elevation . . . Oct 12, 2011 at 13:44
• Difference in road length due to elevational changes is what OP implies.
– Chris
Oct 12, 2011 at 13:52
• Clearly you guys do not live in SF Oct 13, 2011 at 2:25
• 25 grade in San Francisco datapointed.net/visualizations/maps/san-francisco/streets-slope = about a 3% error
– user19129
Jun 14, 2013 at 18:48

I doubt it. Since the length of a sloped road would be `sqrt(1+x^2)`-times the length of the flat one (where `x` is the slope). For low values of `x`, this is roughly `1+1/2*x^2`, which is rather low, eg. for a 10 % slope, you get an error of 0.5 %. Not considering the actual lane you drive probably has a similar error.