Author Topic: Garmin Edge track/course/point limits  (Read 8496 times)

Garmin Edge track/course/point limits
« on: 05 May, 2017, 04:01:26 pm »
My Garmin Edge 810 has freaked out on my last two 200s when following a self-plotted TCX RwGPS routes.

On the first, it crashed and reset at around 130km and although reloading the route worked, ride data to that point was lost and I had to dig out the .fit file to join with the recorded remainder. On the second, it seemed to lose the route completely at a similar distance, but again was fine after a save and restart.

This is hasn't happened before -- I usually split rides into inter-control stretches, but on these two, I plotted the whole route and instead marked controls with a custom cuesheet. The second bit worked, the first bit clearly didn't.

Anyway, I now gather the crashing/failing is all to do with the Edge's inability to work with more than a limited number of 'route things'. The question is, what are those things and what are the limits?

My cursory research has revealed a number of terms – track points, course points, route points, points -- and different sites/tools seem to use these terms interchangeably to mean different things.

On GPSies, for instance, I can reduce 'points' to 500 and still have 2600 'trackpoints' – so what's the difference and which is the important one for Garmin happiness?

Garmin, on the other hand, says "The Edge 510, 520, 800, 810, 820, 1000 and Edge Explore 820/1000 [have] a limit of 200 course points per individual course." But if course points are the point-to-point positions on a line that define the route that follows a road on a map, then that doesn't strike me as very many for even a 20-mile route...

Is there a solid primer on this stuff that explains the intricacies and terminology in a Gamin context..?

frankly frankie

  • I kid you not
    • Fuchsiaphile
Re: Garmin Edge track/course/point limits
« Reply #1 on: 05 May, 2017, 05:15:51 pm »
Garmin themselves use these terms inconsistently.

This page
http://www.aukadia.net/gps/lwg_1.htm
but it's not up-to-date on Edges and their default format, 'Courses'.  I would suggest a Coursepoint equates to a User Waypoint or possibly to a Routepoint (or Viapoint - the term that Garmin sometimes uses, though if you inspect a GPX file they are tagged as <rtept>). 

If they are equivalent to Waypoints, then those are just markers (like points of interest) with no particular navigational power, except Coursepoints make use of a 'Type' property that can be 'Left Turn' or 'Right Turn' etc which maybe can activate a prompt.
If they are like Routepoints, well 200 Routepoints would get you a lot further than 20 miles if you (and your GPS) make the very reasonable assumption that the only way from one point to the next is the shortest way by road.  Even in UK laney conditions with frequent junctions, that would get you at least 150 miles.

The 'small' points that make up the wiggley line you follow when you are following a Course are Trackpoints.  You would normally expect those to be less than 100 yards apart, or say 18 to the mile, so yes 200 of those would only get you 11 miles.  But the Edge can probably use Courses of up to 10,000 of these points (don't know the precise figure, but you certainly don't need to reduce them to 500 - however RWGPS is notorious in my mind for exporting files with over-large numbers of points, it is something to watch out for).
when you're dead you're done, so let the good times roll

Re: Garmin Edge track/course/point limits
« Reply #2 on: 26 October, 2021, 01:34:44 pm »
So it seems Garmin hasn't really moved on in the four years I last had this problem – and searching for a solution for my similarly afflicted Edge 1030 Plus brings me back to my original post...

I've been syncing routes directly from RwGPS (i.e. via Garmin Connect) since upgrading to an Edge 1030 Plus, since that preserves the 'course points' – the manually added POI markers for food, controls etc that give a useful on-device alert when they're approached. No problems so far with routes up to 300km.

However, trying the same with a 400km route at the weekend confused the Edge enormously. At some point, it decided I was riding a ~300km route (it seemed to vary during the ride) and, when I reached 300km, it stopped giving turn-by-turn directions and any other meaningful ride data altogether – instead just displaying a barely distinguishable line (not even any direction arrows). The ride was otherwise recorded properly.

Clearly the Edge was overwhelmed by something, but having just off the phone with Garmin tech support, I have no idea what. They maintain the Edge is limited to 200 'course points' to define a route, which is clearly wrong. I'm assuming they're confusing the manually added points for Food, etc (which their own routing tool calls 'course points') with 'track points' – the points that define a track. But worryingly, they're unable to tell me what the track point limit is as they don't seem to understand the question.

Whatever the case, RwGPS seems like the ultimate culprit – its original 400km GPX had 18443 track points, which seems excessive. Since RwGPS is my plotting tool of choice, I don't want to re-plot everything in Garmin Connect – but I also want to keep my manual course points, which means exporting and reducing a GPX file isn't an option.

So I guess that despite this being 2021, a £500 Garmin bike navigation device still needs to be spoon fed long routes to stop it from crashing. What a swizz.

JonB

  • Granny Ring ... Yes Please!
Re: Garmin Edge track/course/point limits
« Reply #3 on: 27 October, 2021, 10:08:53 am »
That's interesting, I've done two 600s with my 530 and on both rides it's stopped any turn by turn directions at around 500km.  At this point I can still see the magenta line on the map representing the route but it also draws a heavier magenta straight line to the finish i.e. not on the roads.  This was very confusing when it first appeared but when I realised the route was still on the map I was able to navigate easily enough.  I guess the next time I do longer rides I'll split them to avoid this but it would be nice to know how to when a route has too many 'points' (deliberately avoiding useing the nomenclature of trackpoints, coursepoints etc because i've never got on top of this) and where to get this information from.
I previously had an extrex and that was a bit of a faff but at least I knew the limit was 10,000 trackpoints and I could measure these in Basecamp and either split or reduce the trackpoints.

Re: Garmin Edge track/course/point limits
« Reply #4 on: 27 October, 2021, 10:43:27 am »
I'm still talking to Garmin tech support about this, so I'll update if/when I know more.

I've also done a bit more digging with trackpoints and my initial experiments suggest that Garmin Connect exports GPX files with more trackpoints than the equivalent RwGPS export.  What I don't know is how that relates to RwGPS/Garmin Connect tracks synced  to the device rather than exported and uploaded. I imagine these involve native FIT files and that they also use 'points' of some sort, hence why the route upload method seems to make no difference.

Ultimately, it looks like the Edge is being overwhelmed by the data it needs to process for the route remaining once it's reaches a certain distance (with the data recorded for that distance being a factor). I can only see that being based on 'trackpoints'. Incidentally, I did stop and reload the broken 400km route at about 350km into the and it didn't fix the problem – that was the reliable solution for other Edge devices I've used when faced with this problem.

JonB: Your problem matches mine exactly – I also got the birds-eye route to the end point.

There is more discussion about what these point things are called, but I'm not sure it helps that much... https://yacf.co.uk/forum/index.php?topic=119916.0

JonB

  • Granny Ring ... Yes Please!
Re: Garmin Edge track/course/point limits
« Reply #5 on: 27 October, 2021, 02:17:05 pm »
I'm still talking to Garmin tech support about this, so I'll update if/when I know more.
Great, would appreciate that

Incidentally, I did stop and reload the broken 400km route at about 350km into the and it didn't fix the problem – that was the reliable solution for other Edge devices I've used when faced with this problem.
Yes, I wondered about doing that but decided that whilst I could still follow the line on the road I didn't want to destabilise things further

There is more discussion about what these point things are called, but I'm not sure it helps that much... https://yacf.co.uk/forum/index.php?topic=119916.0
Ha, not sure my brain has capacity for that at the moment  ;)

Re: Garmin Edge track/course/point limits
« Reply #6 on: 27 October, 2021, 02:33:54 pm »
I've also done a bit more digging with trackpoints and my initial experiments suggest that Garmin Connect exports GPX files with more trackpoints than the equivalent RwGPS export. 
This isn't correct. Ride with GPS routes are notorious for generating way more trackpoints than required. Garmin connect turns these into coursepoints. You can do this yourself through ineptitude and selecting the wrong export options. DAMHIKT.

Quote
What I don't know is how that relates to RwGPS/Garmin Connect tracks synced  to the device rather than exported and uploaded. I imagine these involve native FIT files and that they also use 'points' of some sort, hence why the route upload method seems to make no difference.

If you sync with RwGPS via their Connect IQ app it syncs a FIT file. If you export as a file from RwGPS you choose the file type- which allows you to retain custom cues and waypoints.

Any device is going to have a limit- they have a finite memory after all. The assumption from Garmin is that you're not going to reach that limit. That's not unreasonable- how many people actually ride 600km in a single ride? A vanishingly small portion of their user base.


It's worth reading this: https://ridewithgps.com/help/export-file-formats
and thinking how that meshes with your use case.

Re: Garmin Edge track/course/point limits
« Reply #7 on: 27 October, 2021, 03:12:50 pm »
Any device is going to have a limit- they have a finite memory after all. The assumption from Garmin is that you're not going to reach that limit. That's not unreasonable- how many people actually ride 600km in a single ride? A vanishingly small portion of their user base.

The issue for me isn't that there's a limit per se, it's that the device loads a route without complaint and appears to be working normally, but then gives stops routing and gives erroneous 'ride remaining' forecasts without warning at some point due to apparently being unable to process more than an indeterminate length of continuous ride.

Ride recording and navigation are primary functions of these devices and the fact that Garmin's top-end model still can't do it faultlessly (or fail to do it elegantly) is reasonable grounds for complaint, I think.

(And don't get me started on the device's inability to properly calculate 'ETA at Dest.' properly for a pre-loaded route...)

frankly frankie

  • I kid you not
    • Fuchsiaphile
Re: Garmin Edge track/course/point limits
« Reply #8 on: 27 October, 2021, 11:42:30 pm »
You (all) do realise that >300km is an 'unreasonable' distance beyond which nothing is going to work properly.
when you're dead you're done, so let the good times roll

Re: Garmin Edge track/course/point limits
« Reply #9 on: 28 October, 2021, 10:36:30 am »
I always know I am in deep trouble when your search only returns your own posting from 4 years ago.

I have grown up via Garmin 200, 510, 520, 530 and like to keep the routes as simple as possible,

A question are you using the Garmin "Turn Guidance" , ie getting the big white arrows at turns. I have always found these a problem as the Garmin is using its internal map to attempt to construct a route by finding connections between the track points within the downloaded course/route. This is what happens during the sometimes lengthy "calculation phase when you select "ride". If it can't find a connection it will try to form the route using your downloaded route as a "suggestion" only, not good if it is a mandatory route.

The longer the route the more likely it will find issues as the OSM maps on which Garmin maps are built are created by well meaning but human contributors, there will be issues. The calculation function is very processor and memory intensive and prone to issues as the route becomes bigger.

As I am a control freak and don't want to leave it up to Garmin to construct its version of my course I turn off the "Turn Guidance" and rely on the "Course Points" (ie cue entries build by RWGPS for the turns plus other custom cues). Only RWGPS Fit or TCX downloads support the cue entries. Using this Course Point guidance alternative eliminates the "Calculation" phase, most Garmin "Navigation" issues and leves me in control of that prompts I get and when but the downside is that the user interface is slightly less elegant.

A typical RWGPS route consists of thousands of "Track Points" (typically one per 30-50 metres, maybe longer if more rural roads)

<Track>
        <Trackpoint>
          <Time>2017-04-27T01:09:44Z</Time>
          <Position>
            <LatitudeDegrees>-35.72934</LatitudeDegrees>
            <LongitudeDegrees>147.31004</LongitudeDegrees>
          </Position>
          <AltitudeMeters>263</AltitudeMeters>
          <DistanceMeters>0</DistanceMeters>
        </Trackpoint>
        <Trackpoint>
          <Time>2017-04-27T01:09:54Z</Time>
          <Position>
            <LatitudeDegrees>-35.72867</LatitudeDegrees>
            <LongitudeDegrees>147.31053</LongitudeDegrees>
          </Position>
          <AltitudeMeters>262.1</AltitudeMeters>
          <DistanceMeters>86.738</DistanceMeters>
        </Trackpoint>
        ............

and up to 200 "Course Points"

 <CoursePoint>
        <Name>Start of r</Name>
        <Time>2017-04-27T01:09:44Z</Time>
        <Position>
          <LatitudeDegrees>-35.72934</LatitudeDegrees>
          <LongitudeDegrees>147.31004</LongitudeDegrees>
        </Position>
        <PointType>Generic</PointType>
        <Notes>Start of route</Notes>
      </CoursePoint>
      <CoursePoint>
        <Name>Murray St</Name>
        <Time>2017-04-27T01:10:04Z</Time>
        <Position>
          <LatitudeDegrees>-35.72794</LatitudeDegrees>
          <LongitudeDegrees>147.31105</LongitudeDegrees>
        </Position>
        <PointType>Left</PointType>
        <Notes>Turn left onto Murray St</Notes>
      </CoursePoint>
      <CoursePoint>
        <Name>Towards Ra</Name>
        <Time>2017-04-27T01:13:34Z</Time>
        <Position>
          <LatitudeDegrees>-35.72647</LatitudeDegrees>
          <LongitudeDegrees>147.30551</LongitudeDegrees>
        </Position>
        <PointType>Right</PointType>
        <Notes>Turn right towards Railway Parade</Notes>
      </CoursePoint>

PS There are utilities that take large routes and apply maths to reduce the trackpoints to less than the 10,000 apparent "limit", wilkyboy used these on his PBP 2019 routes

Re: Garmin Edge track/course/point limits
« Reply #10 on: 28 October, 2021, 10:54:11 am »
You (all) do realise that >300km is an 'unreasonable' distance beyond which nothing is going to work properly.

My app has no problem with routes that long*. Modern ££££ hardware shouldn't choke on data measured in kilobytes, and if it does have an upper limit it should fail gracefully. Otherwise demand your money back.

(* ok, it crops routes to about 2000 km, but it informs the user and is fully tested below that)

Re: Garmin Edge track/course/point limits
« Reply #11 on: 28 October, 2021, 07:19:17 pm »
You (all) do realise that >300km is an 'unreasonable' distance beyond which nothing is going to work properly.

We should of course, point out that it’s not the length of the ride but the number of track points (substitute course points if using that format) causing the issue. The devices in question are quite capable of navigating a 600km track in one go. The first rider back on LEL 2017 used the two 700km north and south tracks I created quite successfully. Because they weren’t the bloated abominations that RWGPS chucks out.

Feanor

  • It's mostly downhill from here.
Re: Garmin Edge track/course/point limits
« Reply #12 on: 28 October, 2021, 08:21:34 pm »
Yes, like LP says, it's down to the number of points.

In the Garmin world, a Route has Routepoints, which are fairly sparse, and the routing engine will use the maps to generate a route and provide turn-by-turn instructions.

A Track contains Trackpoints, which are basically the same as routepoints, in as much as they contain a lat/long. But a track typically contains thousands of trackpoints. Some websites will produce super-bloated tracks. Other websites will thin these down for you.

If you ask a Garmin to navigate a Route, it will generally work fine. It has a sparse number of points, and the routing engine will use the maps to link them up.
If you ask a Garmin to navigate a Track, it's a very different thing. Different devices can do this to different levels of success.

You might well wonder 'why is this'? Both a route and track are just a list of lat/longs to be linked up.
And that's a fair question.
But it's just down to hysterical raisins. The routing engine simply cannot accept a massive list of points, even if they are within the trackpoint limit. The trackpoint limit is not the same as the number of points the routing engine can handle.

On PBP, I had an outbound and return tracks loaded, all within the trackpoint limit.
But when I attempted to follow them using the routing engine, it failed after a few minutes of grinding.

A common solution is to simply not invoke the routing engine.
Just set the track to display on the map, and follow it manually.
This is what I did on PBP.

Yes, all a bit crap. But there you have it.