Discrepancy in route calculator

Forum guidelines BT super discount
Site Issues Training Log & Site Support » Discrepancy in route calculator Rss Feed  
Moderators: k9car363, alicefoeller Reply
2009-10-03 4:13 PM

User image

Master
1882
1000500100100100252525
Chandler, Arizona
Subject: Discrepancy in route calculator

I've noticed that there is always discrepancy in miles and feet of climbing between manually mapping out a ride in the route calculator and doing it through a Garmin decvice. I usually will map out a ride and then go ride it. When I get back I like to upload the same route from my Garmin because I figure it would be more exact. The Garmin data is always substantially lower. Any reason for this?

 

Thanks!

2009-10-03 5:02 PM
in reply to: #2440954

User image

Champion
11641
50005000100050010025
Fairport, NY
Subject: RE: Discrepancy in route calculator
There will always be some difference between the two as they're very different methodologies being used to measure different things.

The Route Tracker (or more accurately, Google Maps as that's the underlying technology) is measuring the distance on a map on your computer screen and then converting that to feet/kms/miles and the Garmin is using the GPS system.  You would have to click on every exact point, to within 3 feet, on the Route Tracker to get the same datapoints that the Garmin is measuring, and even then there would probably be some variation due to the different methodologies being used.

The elevation measurements are also using different technologies and those values are based the exact locations being mapped. They may come close, but I very much doubt you'd ever see them match. How much of a variation are you seeing?
2009-10-05 11:32 PM
in reply to: #2440986

User image

Master
1882
1000500100100100252525
Chandler, Arizona
Subject: RE: Discrepancy in route calculator

marmadaddy - 2009-10-03 3:02 PM There will always be some difference between the two as they're very different methodologies being used to measure different things.

The Route Tracker (or more accurately, Google Maps as that's the underlying technology) is measuring the distance on a map on your computer screen and then converting that to feet/kms/miles and the Garmin is using the GPS system.  You would have to click on every exact point, to within 3 feet, on the Route Tracker to get the same datapoints that the Garmin is measuring, and even then there would probably be some variation due to the different methodologies being used.

The elevation measurements are also using different technologies and those values are based the exact locations being mapped. They may come close, but I very much doubt you'd ever see them match. How much of a variation are you seeing?

 

The major vairation that I'm seeing is in elevation. I did a 72 mile ride this weekend that has 3,400 of climbing in it. When I upload from the Garim the distance is pretty close but the Garmin data said that the elevation was less then 2,000. I'm not sure if the Garmin is inputing a net figure or what but just thought I'd ask. I actually deleted the route from the Garmin because I know it's not right. I guess it would help if I had links for the two different rides to show you. Maybe I'll do that with tomorrow's ride. Anyways, thanks for the help. 

New Thread
Site Issues Training Log & Site Support » Discrepancy in route calculator Rss Feed