Km-indication vs distance

This is the Map Pedometer Forum
Post Reply
Ivanhoe
Posts: 12
Joined: Thu Feb 06, 2014 10:37 am

Km-indication vs distance

Post by Ivanhoe »

When I measuere a route using run/walk there is a difference between the distance measured and the km-indication. On average it's 1,3m/km. This means that for example the 100km point isn't on 100km but on 99km870. When I use straight line this problem doesn't exist. What's the correct 100km point? The total distance or the 100km point? I suppose the same problem goes for driving.
admin
Site Admin
Posts: 298
Joined: Thu Jul 21, 2011 9:51 am

Re: Km-indication vs distance

Post by admin »

When creating a run/walk/cycling/driving route, we use the total distance provided by Google for each segment between the points clicked on the map. When creating a straight line segment between points, we use a Google provided distance calculation to determine the distance of each segment. The mile/km indicators are placed on the map based on Google provided distance calculations between each point in a line segment. The calculation of straight line distance markers is identical to the calculation of the entire straight line segment. The calculation method for the distance markers for run/walk/cycling/driving segments differs from the total segment length since we recompute partial segment distances using the Google provided distance calculation. Since the calculation method is different, a slight variation (you measured 99.87% distance marks versus total distance) may be seen in the reported distances.

We chose to use the Google provided distance for a calculated segment since Google may have optimized/corrected the distance calculation over the total segment length. The accuracy of distance calculations between latitude/longitude points on earth can also vary based on the radius of the earth, elevations changes, etc.

In your post, you asked which is the correct distance. The answer is that both distances are "correct" as all distances reported on Map Pedometer are approximate distances. The distances aren't guaranteed to be accurate and should only be used for "entertainment" purposes. The distances reported on Map Pedometer should NOT be used where 100% accuracy is needed such as with property line surveys.

Ivanhoe wrote:When I measuere a route using run/walk there is a difference between the distance measured and the km-indication. On average it's 1,3m/km. This means that for example the 100km point isn't on 100km but on 99km870. When I use straight line this problem doesn't exist. What's the correct 100km point? The total distance or the 100km point? I suppose the same problem goes for driving.
Post Reply