Consider a route on a map between two waypoints. Google Maps will calculate the distance between the two, and display it for you. This is very handy. Thank you Google Maps!

Consider a route where the route is straight, and the distance 'as the crow flies' between those points is 1 mile. Change that scenario to include a hill at a 30 degree slope between each point.

If the route contains hills with significant inclines or declines, does the calculated distance represent the true distance?

  • It is worth noting that a stetch of road that is 8% longer in surface distance than map distance is very steep (That is what grade means, after all). So these adjustments are generally quite small...
    – dmckee
    Commented Jul 25, 2009 at 16:48

2 Answers 2


Yes. Based on several trips through the mountains that the Google map directions were accurate for the trip

  • Interesting. I'd guess that each component of a road/path in their data also contains information about its physical distance.
    – jtbandes
    Commented Jul 25, 2009 at 5:45
  • There are many freely available elevation layers, I'm sure google makes use of one. The USGS has a huge free dataset available for the whole US.
    – Paul McMillan
    Commented Jul 25, 2009 at 8:40

No, according to Todd Gardiner:

Google Maps (and Google Earth) only calculate "as the crow flies" distance using the map coordinates of the points of the route or ruler tool. It does not use the terrain data for these calculations.

on Aug 28, 2015. Of course may have changed since (and he could have been wrong), however the difference in distance is clearly small (or this Q might not have been asked) and though Google Maps has a lot of topographical data allowing for that in distance (rather than elevation) calculations would be a lot of work for so little benefit that is seems unlikely to me they would bother.

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