Courses: Average Speed - Edge 530

A good question and one I have asked RWGPS "Help" Desk several times but they each time proceed to tell me about the average estimated speed which displays for Premium members and which has no relationship to the course speeds for exported courses.

The Courses (either FIT or TCX) contain thousands of "track points" defining the course/route and these consist of a position (Latitude. & Longitude), elevation and to give them a unique ID they have a generated date / time stamp. The "average speed" on the Garmin seems to  be calculated by dividing the total distabce by a total time (last track point date / time stamp minus the first date / time stamp). There is also a <TotalTimeSeconds> field which has no relationship to the calculated average speed.

So I have asked them how they generate the date / time stamps for the track points and have never got an answer, seems random as it will give a speed of 5kph for one course and if I export the same course 5 minutes later it will be 15 or more.

Having said that there are some planing sites that will allow you to nominate an average speed and this is then used to generate the date / time stamps for the exported route. Garmin Connect is one such site, I prefer RWGPS but sometimes import a Course to Gamin Connect so I can set the average speed.

In the TCX below the <TotalTimeSeconds>. is shown as 3566** seconds, less than an hour whereas the difference between the Last & First point time stamps is about 9h55m and Garmin says average speed 10.59kph (ie 105/9h:55m)

If you find an answer to this mystery please let me know.

<?xml version="1.0" encoding="UTF-8"?>
<TrainingCenterDatabase xmlns="">www.garmin.com/.../v2" xmlns:xsi="">www.w3.org/.../XMLSchema-instance" xsi:schemaLocation="www.garmin.com/.../v2 ">www.garmin.com/.../TrainingCenterDatabasev2.xsd">
  <Folders>
    <Courses>
      <CourseFolder Name="Courses">
        <CourseNameRef>
          <Id>Winery-Tour</Id>
        </CourseNameRef>
      </CourseFolder>
    </Courses>
  </Folders>
  <Courses>
    <Course>
      <Name>Winery-Tour</Name>
      <Lap>
        <TotalTimeSeconds>3566</TotalTimeSeconds>     **(strangely enough 3566 is exactly the number of trackpoints in the file?)
        <DistanceMeters>105020.0</DistanceMeters>
        <BeginPosition>
          <LatitudeDegrees>-33.62321</LatitudeDegrees>
          <LongitudeDegrees>151.15302</LongitudeDegrees>
        </BeginPosition>
        <EndPosition>
          <LatitudeDegrees>-33.62274</LatitudeDegrees>
          <LongitudeDegrees>151.15363</LongitudeDegrees>
        </EndPosition>
        <Intensity>Active</Intensity>
      </Lap>
      <Track>
        <Trackpoint>
          <Time>2021-06-19T06:13:22Z</Time>
          <Position>
            <LatitudeDegrees>-33.62321</LatitudeDegrees>
            <LongitudeDegrees>151.15302</LongitudeDegrees>
          </Position>
          <AltitudeMeters>211.2</AltitudeMeters>
          <DistanceMeters>0</DistanceMeters>
        </Trackpoint>

        ......(3,564 trackpoints)......

(Last Trackpoint)    

<Trackpoint>
          <Time>2021-06-19T16:08:22Z</Time>
          <Position>
            <LatitudeDegrees>-33.62274</LatitudeDegrees>
            <LongitudeDegrees>151.15363</LongitudeDegrees>
          </Position>
          <AltitudeMeters>213.8</AltitudeMeters>
          <DistanceMeters>105020.193</DistanceMeters>
        </Trackpoint>
      </Track>
     

Thanks for the information. I've also put in a support question to RWGPS but not had an answer yet. I'll let you know if they come back with anything new. Not holding my breath.

So, contacted RWGPS and they basically told me to contact Garmin. So I contacted Garmin, Garmin told me to use Garmin Connect, which I did, it works fine and you can even change the average speed using "Pace Settings".

I looked at the RWGPD .tcx file and noticed that the time difference between the time stamp on the first trackpoint and last trackpoint equalled the estimated time shown when loaded to the 530 and therefore the incorrect average speed.

I've contacted RWGPS again pointing this out as it can only be coming from RWGPS. 

I'll post what happens. 

At one point I thought the ability to set a course time was only available through their paid service (RWGPS)

I wasn't aware you could change estimated speed, only that it is calculated based on previous rides over 10 miles. 

ridewithgps.com/.../estimated-time

So, I've had a reply from RWGPS that doesn't help / make sense. Here is their response and my reply:

"I took a closer look into this with a colleague of mine, the low average speed you are seeing on your Garmin is due to the TCX Course file cues we insert into the device for cue notifications as you navigate a route. 

The only downside to a TCX file for navigation is the Virtual Partner. When we create a TCX Course file for a pre-planned route, we have to embed fake timestamps on each point, which is used for the virtual partner speed on the GPS unit. As a result, you’ll end up racing against the virtual partner and thus have not your typical avg speed estimation for a route from the Garmin device. 

I hope this helps explain what you're seeing. If you have any follow up questions or concerns please let me know!"

And this is my reply:

"I’m not sure I understand this. If this is the case why does Garmin Connect create route files with times either at a default of 25kph or at an average speed that can set to any value in via their Pace Settings option. These download to the 530 device without problem and presumably work just fine with the Virtual Partner.

In fact if I wanted to use the Virtual Partner I would expect as a starting point for the time trackpoints to be based on my average speed not a speed lower than walking pace.

It seems to me this is either a bug or something that hasn’t been thought through.

Can you please put this forward for either a fix or a future enhancement."

I won't be holding my breath.

RWGPS reply:

"The reason you don't see this inaccurate average time calcuation on Garmin Connect created courses is because these are created within the Garmin routing system. For our routes and navigational cues to be compatible with this routing system, we need to add in each cue asssociated with a false time stamp within the route file itself. That is the method that we have been using for 10+ years to provide cue (and custom cue) notifications for routes created with our service to be compatible for use while navigating on Garmin units. I will certainly pass on your feedback on this process to our development team for their consideration in future."

Still not sure this makes sense but nothing is going to change. 

Does anyone know if Komoot is any better?

In my experience the 530 unit will ignore the pace set with courses created in komoot, strava and garmin connect.

This is annoying for me as i like to have an estimate of when i will get home. I have even created a duplicate course in GC and then used the pace calculator field (you don't seem to be able to adjust the pace for a course synched from elsewhere). I have even adjusted the virtual partner speed. When I fire up the course on my unit it has the speed entered on GC but when i press ride and it calculates it over rides it with a different number. 

Typically i have it set to 27 or 28kph and the unit will use 22kph.

I'd love to have an answer to this !

MB