ridewithgps / bikeroutetoaster total elevation

Lucky Douglas
Lucky Douglas Posts: 155
edited October 2011 in Road beginners
I've clicked round a 4 day route in ridewithgps and the total elevation came in at 11,500 ft.
That was more than I was expecting so I did the same route on bikeroutetoaster and it reckoned 6,400 ft.

I know these are estimates, but wouldn't have expected such a variance. Does anyone know how they arrive at these figures? Any ideas why such a difference?

Comments

  • Gizmodo
    Gizmodo Posts: 1,928
    From the RideWithGPS.com FAQ: http://ridewithgps.com/faq#elevation_accuracy
    Many people contact us to tell us our elevations are not the same as they see on their altimeter/GPS units, Garmin Connect, MMR, etc. Unfortunately, this is always going to be the case because no one actually has 100% accurate elevation information. In reality, there is no sure fire way to exactly calculate the gain/loss of a particular route! However, we can get as close as possible to accurate, which is a difficult task. Currently, we are using some complex signal processing analysis to smooth out elevation data recorded from either your GPS unit, or from the USGS elevation dataset we use when mapping a new route. We believe we have the most accurate elevation data of any online mapping service, however, we are always wanting to improve it. Please contact us if you have experience processing noisy datasets using signal processing techniques or statistical analysis and have any ideas that could help. We would love to hear from you!
  • Gizmodo wrote:
    From the RideWithGPS.com FAQ: http://ridewithgps.com/faq#elevation_accuracy
    Many people contact us to tell us our elevations are not the same as they see on their altimeter/GPS units, Garmin Connect, MMR, etc. Unfortunately, this is always going to be the case because no one actually has 100% accurate elevation information. In reality, there is no sure fire way to exactly calculate the gain/loss of a particular route! However, we can get as close as possible to accurate, which is a difficult task. Currently, we are using some complex signal processing analysis to smooth out elevation data recorded from either your GPS unit, or from the USGS elevation dataset we use when mapping a new route. We believe we have the most accurate elevation data of any online mapping service, however, we are always wanting to improve it. Please contact us if you have experience processing noisy datasets using signal processing techniques or statistical analysis and have any ideas that could help. We would love to hear from you!
    Thanks - I think the FAQ extract is about smoothing minor spikes, rather than c.100% variations.
    The route is the the NCN45 - anyone know whether 6000ft or 11.500ft is nearer the mark? .
  • John.T
    John.T Posts: 3,698
    Gizmodo wrote:
    From the RideWithGPS.com FAQ: http://ridewithgps.com/faq#elevation_accuracy
    Many people contact us to tell us our elevations are not the same as they see on their altimeter/GPS units, Garmin Connect, MMR, etc. Unfortunately, this is always going to be the case because no one actually has 100% accurate elevation information. In reality, there is no sure fire way to exactly calculate the gain/loss of a particular route! However, we can get as close as possible to accurate, which is a difficult task. Currently, we are using some complex signal processing analysis to smooth out elevation data recorded from either your GPS unit, or from the USGS elevation dataset we use when mapping a new route. We believe we have the most accurate elevation data of any online mapping service, however, we are always wanting to improve it. Please contact us if you have experience processing noisy datasets using signal processing techniques or statistical analysis and have any ideas that could help. We would love to hear from you!
    This refers to US data. The readings in the UK are high. I stopped using their corrections on their advice as they said the barometric altimeter in my Edge 500 would give more accurate results. So if you plan a route on RWGPS you will get a high figure for the UK. What mapping does Bikeroutetoaster use. If OS then their figure will be nearer the mark. If they use Google (the same as RWGPS) then they must use a different algorithm. If you have a computer with a barometric altimeter just go out and do a ride, upload it to both and see which comes up closest to the computer.
  • The route is the the NCN45 - anyone know whether 6000ft or 11.500ft is nearer the mark? .
    Post a link to a .gpx file and I'll run it through memory map.
  • The route is the the NCN45 - anyone know whether 6000ft or 11.500ft is nearer the mark? .
    Post a link to a .gpx file and I'll run it through memory map.
    That's a kind offer thanks Rothers.
    I've got memorymap myself but hadn't thought to try what you suggested. What it did show up is that the ridewithgps file is nacked.
    I think I'm going to have to click the whole thing into memorymap from scratch!