Author Topic: Should I include controls in GPS file?  (Read 3856 times)

telstarbox

  • Loving the lanes
Should I include controls in GPS file?
« on: August 16, 2017, 10:27:37 am »
A question for the Garmin crew.

I'm setting up a ride and so far I have prepared the routesheet and brevet card which both list the control locations and distances. In parallel with this I have been working on a route saved in Strava which I can then export as a .GPX file to distribute to riders.

I've never used a Garmin to navigate but if you use one, do you prefer it to show an 'alert' when you are nearly at a control? If so, is there an easy way for me to add these to the GPX file? If not then is it best to tweak the track, for example turning in and then out of the nearest side road?
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T42

  • Tea tank
Re: Should I include controls in GPS file?
« Reply #1 on: August 16, 2017, 11:30:43 am »
Rather messing about with the GPX I created a separate file of waypoints for PBP controls, loaded them both into the Garmin (eTrex 30) and set both to show on the map. Then I added "Next Waypoint" and "ETA" data fields to the map display.  In conjunction with a list of controls and closing times taped to the top tube, it worked quite nicely.
I've dusted all those old bottles and set them up straight.

vorsprung

  • Opposites Attract
    • Audaxing
Re: Should I include controls in GPS file?
« Reply #2 on: August 16, 2017, 11:40:34 am »
Unless you specifically test the file on a particular device you don't know how the extra info above and beyond a simple track line will work

So add whatever you like but don't assume people who aren't using an eTrex30 are seeing what you are seeing

I just make a vanilla gpx file with less than 10,000 points per track and that's what people have to deal with.  This has worked well, had no complaints

The LEL approach with one track per stage (per control) was pretty good I thought
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telstarbox

  • Loving the lanes
Re: Should I include controls in GPS file?
« Reply #3 on: August 16, 2017, 12:26:06 pm »
I don't know what devices people will bring, but a .GPX file should work universally shouldn't it?
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Pingu

  • Put away those fiery biscuits!
  • Mrs Pingu's domestique
    • the Igloo
Re: Should I include controls in GPS file?
« Reply #4 on: August 16, 2017, 12:35:47 pm »
I use an etrex30. I prefer to create my own GPX files based on the routesheet, though I will check against a provided GPX if available. Like T42, I add the controls as waypoints separately.[color]

fuaran

  • rothair gasta
Re: Should I include controls in GPS file?
« Reply #5 on: August 16, 2017, 12:44:19 pm »
Yes, I think you should include the controls as waypoints, in the GPX file.
Anyone using it on their own device can then figure out what to do with them. eg you can set them as proximity waypoints if you want. Or create your own route based on them.

Its not always obvious from the routesheet, where the controls actually are. A GPX makes it a lot simpler to find them on a map.

Kim

  • Timelord
Re: Should I include controls in GPS file?
« Reply #6 on: August 16, 2017, 01:11:34 pm »
Yes, I think you should include the controls as waypoints, in the GPX file.

Seconded.  It genuinely wouldn't occur to me not to.

While I expect that some user/device combinations wouldn't make use of them, I can't believe the mere presence of waypoints in a GPX would actually cause problems navigating the track, would it?

Multiple tracks in a GPX seems to be a bad idea these days, from a usability standpoint if not a compatibility one.  Many people seem to expect a GPX to contain a single track and nothing else, and doing otherwise is likely to confuse them.  It also makes things easier to work with if the only tool you have available is a file manager (eg. on an Android phone).  I'll only bundle multiple tracks/routes in a single GPX for my own use.
To ride the Windcheetah, first, you must embrace the cantilever...

telstarbox

  • Loving the lanes
Re: Should I include controls in GPS file?
« Reply #7 on: August 16, 2017, 01:30:49 pm »
Thanks everyone.

The GPX output from Strava is a long list of coordinates, for example:

Code: [Select]
<trkpt lat="51.45349" lon="-0.034780000000000005">
    <ele>29.200000000000003</ele>
   </trkpt>

So I also need to insert each control using
Code: [Select]
<wpt> </wpt> tags?
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jiberjaber

  • ... Fancy Pants \o/ ...
  • ACME S&M^2
Re: Should I include controls in GPS file?
« Reply #8 on: August 16, 2017, 03:14:49 pm »
Perhaps just put the route on RWGPS, plonk some POI at the controls and circulate the link to that, then anyone can bake their own version suitable for their device.... otherwise you run the risk of a load of moaning because you didn't cater for $device etc...

Camaudax is a good example of this (though Nick also does offer the files in a few flavours as well)...

ETA: Here's an example based on your 3 rivers route (I just dropped the info's at random places to give you an example)

https://ridewithgps.com/routes/24276925
Regards,

Joergen

telstarbox

  • Loving the lanes
Re: Should I include controls in GPS file?
« Reply #9 on: August 16, 2017, 03:35:01 pm »
That's great, cheers Jason.
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fuaran

  • rothair gasta
Re: Should I include controls in GPS file?
« Reply #10 on: August 16, 2017, 03:42:41 pm »
ETA: Here's an example based on your 3 rivers route (I just dropped the info's at random places to give you an example)

https://ridewithgps.com/routes/24276925
But it doesn't export the waypoints in the file unless you pay for membership.

Phil W

Re: Should I include controls in GPS file?
« Reply #11 on: August 16, 2017, 06:14:58 pm »
Don't use RWGPS for this as it doesn't export the waypoints unless you have a paid membership. A simple GPX  with a track (less than 10,000 points)  and the controls as waypoints is perfect as a base GPX to provide. Made available as a download without needing to visit any online mapping service.

Re: Should I include controls in GPS file?
« Reply #12 on: August 16, 2017, 06:40:05 pm »
I use Basecamp or Gpxeditor to add waypoints.  Save/export as one file.

frankly frankie

  • I kid you not
    • Fuchsiaphile
Re: Should I include controls in GPS file?
« Reply #13 on: August 16, 2017, 07:06:57 pm »
I agree, Waypoints and Track in a single GPX file, is the way to go, and make the Waypoints accurate enough that they really do identify the control location (eg the entrance gate) - because riders will assume no less.
One reason to have control Waypoints is so that if the Track fails for some reason, the rider may still be able to 'Go To' the Waypoint.  So I would name the Waypoint starting with a number.

Code: [Select]
<trkpt lat="51.45349" lon="-0.034780000000000005">
    <ele>29.200000000000003</ele>
   </trkpt>

<hobbyhorse> Is it any wonder these files get bloated?   >:( The longitude and elevation here are defined to sub-molecular levels of 'accuracy'.  I know its not your fault, I know it's what Strava output, but speaking as one who still cares about bandwidth as much now as I did 20 years ago, this sort of stuff just makes me want to hit someone (possibly myself) with a bag of nails. 5 decimal places is sufficient to comfortably exceed the accuracy of the GPS system itself.  >:( >:( >:(</hobbyhorse>

Quote
So I also need to insert each control using
Code: [Select]
<wpt> </wpt> tags?

But not quite as simple as that.  Your list of Trackpoints is contained in a (or several) <trkseg> wrapper, and this (or these) in turn is contained in a <trk> wrapper.  That is your Track.  The Waypoints have to be outwith the tags enclosing the Track(s), they are not 'part of' the Track.  To be fully compliant, they have to be positioned before the Track, and immediately after the header which usually ends with a </metadata> tag.

An example fairly minimal Waypoint, which places a square red 'bike' symbol on a Garmin map:
Code: [Select]
  <wpt lat="53.0869" lon="-2.3379">
    <name>3 Radway</name>
    <sym>Bike Trail</sym>
  </wpt>

The following would add a proximity alert, in this case 200metres (especially useful for info controls, IHMO - though proximity also has to be set up on each GPS).  There's a limit of 10 (more than 10 will just behave as normal Waypoints).

Code: [Select]
  <wpt lat="53.0869" lon="-2.3379">
    <name>3 Radway</name>
    <sym>Bike Trail</sym>
    <extensions>
      <gpxx:WaypointExtension xmlns:gpxx="http://www.garmin.com/xmlschemas/GpxExtensions/v3">
        <gpxx:Proximity>200.00</gpxx:Proximity>
      </gpxx:WaypointExtension>
    </extensions>
  </wpt>

Perhaps just put the route on RWGPS, plonk some POI at the controls and circulate the link to that, then anyone can bake their own version suitable for their device.... otherwise you run the risk of a load of moaning because you didn't cater for $device etc...

 :( This is the best and worst of all worlds IMHO.  Yes, all the above, but also you give a rider of limited understanding every opportunity to get it wrong and download an unsuitable file.   For this reason, and because it makes the organiser look a bit lazy  ;) I'm agin this.
It's not dark yet but it's getting there.

citoyen

  • Cat 6 Racer
Re: Should I include controls in GPS file?
« Reply #14 on: August 16, 2017, 09:22:18 pm »
Seconded.  It genuinely wouldn't occur to me not to.

I'm the opposite - it wouldn't occur to me to do it. Because I didn't know you could.

Quote
Multiple tracks in a GPX seems to be a bad idea these days, from a usability standpoint if not a compatibility one.  Many people seem to expect a GPX to contain a single track and nothing else, and doing otherwise is likely to confuse them.

I've never tried to use a GPX containing multiple tracks, though I'm vaguely aware that such things exist. One was made available for an audax I did a while ago, the aim being to break the ride down into chunks containing no more than 500 trackpoints each - I didn't use it because I have a modern device that can handle tracks with more than 500 points.

I agree, Waypoints and Track in a single GPX file, is the way to go, and make the Waypoints accurate enough that they really do identify the control location (eg the entrance gate) - because riders will assume no less.
One reason to have control Waypoints is so that if the Track fails for some reason, the rider may still be able to 'Go To' the Waypoint.  So I would name the Waypoint starting with a number.

I can see the sense in that, and I'd like to adopt it as a principle. I get the basic idea that you open the GPX file in a text editor and insert the points manually, but I might need a few more pointers...

Quote
But not quite as simple as that.  Your list of Trackpoints is contained in a (or several) <trkseg> wrapper, and this (or these) in turn is contained in a <trk> wrapper.  That is your Track.  The Waypoints have to be outwith the tags enclosing the Track(s), they are not 'part of' the Track.  To be fully compliant, they have to be positioned before the Track, and immediately after the header which usually ends with a </metadata> tag.

I'm familiar enough with markup language for this to make sense but... Do the waypoints have to be included in their own 'wrapper'?

Quote
:( This is the best and worst of all worlds IMHO.  Yes, all the above, but also you give a rider of limited understanding every opportunity to get it wrong and download an unsuitable file.   For this reason, and because it makes the organiser look a bit lazy  ;) I'm agin this.

I've used RWGPS to plot my routes, but have downloaded them myself and processed them through GPSvisualizer to reduce the file size. I've also created 500-trackpoint versions for those who need such things. I have done this for both versions of my route, and I have also provided links to the routes on RWGPS. I am now I am slightly concerned that I am providing too many choices for riders of limited understanding...

Here's a tangential question: if I'm reducing a 200km track to 500 points on GPSvisualizer, what would be the recommended trackpoint distance threshold? I've experimented with this a bit but have yet to achieve satisfactory results.

telstarbox

  • Loving the lanes
Re: Should I include controls in GPS file?
« Reply #15 on: August 16, 2017, 09:47:46 pm »
Thanks for all the input above.

For info it's 100km with 5 intermediate controls so no issues with multiple days.

(If anyone on here does do the ride, I'm aware that my chosen controls for this one don't define the 100km minimum distance, but a) I'm expecting most people to treat it as a group ride b) I trust people not to cheat for the sake of an A5 certificate and no AUK points at stake.)   
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citoyen

  • Cat 6 Racer
Re: Should I include controls in GPS file?
« Reply #16 on: August 16, 2017, 10:56:40 pm »
I can see the sense in that, and I'd like to adopt it as a principle. I get the basic idea that you open the GPX file in a text editor and insert the points manually, but I might need a few more pointers...

OK, answering my own question, I've been having a play with bikehike and think I've got it sussed now...

I plotted the route in bikehike, added waypoints, then saved it as a gpx track. When I opened it in the text editor, this was at the top of the file, before the <trk>...

Code: [Select]
  <wpt lat="51.314920" lon="0.984210">
    <ele>0</ele>
    <name>INFO</name>
    <sym>Waypoint</sym>
    <type>Generic</type>
  </wpt>
  <wpt lat="51.115010" lon="0.642980">
    <ele>0</ele>
    <name>CONTROL</name>
    <sym>Waypoint</sym>
    <type>Generic</type>
  </wpt>
etc...

Presumably I can cut and paste this chunk of code into my existing GPX files - rather than re-plot all the variants from scratch.

Also, I presume I can strip out the <ele> tags, since they don't appear to contain any useful information.

Also, if I understand correctly, adding the gpxx extension to each waypoint as per frankie's code will provide a proximity warning. So...

Code: [Select]
  <wpt lat="51.314920" lon="0.984210">
    <name>INFO</name>
    <sym>Waypoint</sym>
    <type>Generic</type>
    <extensions>
      <gpxx:WaypointExtension xmlns:gpxx="http://www.garmin.com/xmlschemas/GpxExtensions/v3">
        <gpxx:Proximity>200.00</gpxx:Proximity>
      </gpxx:WaypointExtension>
    </extensions>
  </wpt>
etc...

Does that look right?

fuaran

  • rothair gasta
Re: Should I include controls in GPS file?
« Reply #17 on: August 16, 2017, 11:12:30 pm »
It is worth giving the waypoints useful, unique names. If you have several points named "INFO", you might find that one overwrites the other. At least give it a number, eg INFO1, INFO2 etc.
Also don't make the names too long. Some older Garmins are limited to 6-character names.
You can add a description with the <desc> tag if you want more details.

Not sure how well that supported that proximity gpxx extension is. It will probably work on some Garmins, but not others. It should just be ignored by anything that doesn't support it anyway.

citoyen

  • Cat 6 Racer
Re: Should I include controls in GPS file?
« Reply #18 on: August 16, 2017, 11:18:51 pm »
It is worth giving the waypoints useful, unique names.

Noted.

Quote
You can add a description with the <desc> tag if you want more details.

Is there a handy reference somewhere of all the valid tags that can be included in waypoints?

Also, a list of all the standard symbols?

frankly frankie

  • I kid you not
    • Fuchsiaphile
Re: Should I include controls in GPS file?
« Reply #19 on: August 17, 2017, 09:57:20 am »
Googling "Garmin waypoint symbol names" led to this:
http://freegeographytools.com/2008/garmin-gps-unit-waypoint-icons-table

If you don't define a symbol at all, the Garmin will default, probably to Blue Flag (older models) or Blue Pin (newer models).  As you can see from the examples at the bottom of that page, the 'Pin' is certainly highly visible.
I find Small City very useful (I have it set as my default) to create an 'invisible' waypoint, ie one that doesn't clutter the map with a symbol, otherwise I tend to use Bike Trail which is visible but more compact than the default Pin.

The official GPX documentation (tags and attributes) is here:
http://www.topografix.com/gpx/1/1/

A minimal Waypoint will work if just a pair of lat/lon coordinates and nothing else.  However I'd suggest the minimum spec should really also include a unique Name.  Everything else is optional.
A Name can be up to about 30 chars long, but as already noted there are display issues on small GPS screens.
When naming waypoints, I start with the number first, because otherwise if you do for example this
CONTROL1
CONTROL2
CONTROL3 etc
units with limited displays (6 chars max) will just list them like this
CONTRO
CONTRO
CONTRO
better to have
1CONTR
2CONTR
3CONTR

My take on waypoint naming

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citoyen

  • Cat 6 Racer
Re: Should I include controls in GPS file?
« Reply #20 on: August 17, 2017, 10:28:33 am »
Googling "Garmin waypoint symbol names" led to this:
http://freegeographytools.com/2008/garmin-gps-unit-waypoint-icons-table
...
The official GPX documentation (tags and atributes) is here:
http://www.topografix.com/gpx/1/1/

Excellent, thanks. My google fu is obviously weak at the moment - I didn't manage to find either of those.

Quote
When naming waypoints, I start with the number first...

Good thinking.

frankly frankie

  • I kid you not
    • Fuchsiaphile
Re: Should I include controls in GPS file?
« Reply #21 on: August 17, 2017, 10:36:31 am »
Here's a tangential question: if I'm reducing a 200km track to 500 points on GPSvisualizer, what would be the recommended trackpoint distance threshold? I've experimented with this a bit but have yet to achieve satisfactory results.

I would leave it on the default settings, because only in this way would you get the full cleverness of the Ramer-Douglas-Peucker algorithm ...

Which I think goes something like:
* Find the point that lies closest to a line drawn between its two neighboring points, and delete it.
* Repeat (the distance of 'closest' will steadily increase) until the total number of points is reduced to the number required.

BikeHike is also very good for point reduction.  Better IME than the Garmin tools which tend to go too far (you set a target of 500 and it returns a point count of 237 ...)
Though GPSVis is of course a brilliant site for all sorts of things, I use it all the time.
It's not dark yet but it's getting there.

citoyen

  • Cat 6 Racer
Re: Should I include controls in GPS file?
« Reply #22 on: August 17, 2017, 11:55:41 am »
GPX files for my event now updated to include Waypoints. I hope my entrants appreciate the effort I've taken on their behalf!
 
This has been a most instructive thread. I have also noted that the files downloaded from RWGPS give lat/lon to 6dp, but after processing the files through GPSvisualizer, they are cut to 5dp - presumably this is one of the methods it uses to reduce the file size, which is something I had been wondering about.

Phil W

Re: Should I include controls in GPS file?
« Reply #23 on: August 17, 2017, 12:08:02 pm »
Here's a tangential question: if I'm reducing a 200km track to 500 points on GPSvisualizer, what would be the recommended trackpoint distance threshold? I've experimented with this a bit but have yet to achieve satisfactory results.

I would leave it on the default settings, because only in this way would you get the full cleverness of the Ramer-Douglas-Peucker algorithm ...

Which I think goes something like:
* Find the point that lies closest to a line drawn between its two neighboring points, and delete it.
* Repeat (the distance of 'closest' will steadily increase) until the total number of points is reduced to the number required
The algorithm works by defining a maximum distance (as in deviation from the line of the original track, not length of a track) the new track can differ from the original track.  So if removing a trackpoint causes the new track to differ by more than that maximum distance; it is not removed.  So I'd imagine the ones that work to get below a fixed number of points just adjust the maximum distance till you get there. Though I have seen some shockingly bad ones that just remove points at fixed intervals and leave a track no longer aligned to the original The algorithm is fast and so running it iteratively isn't a worry.  You also get a feel for what setting for a maximum distance brings for a particular length of track. For instance a 300km track will generally be reduced to about 2000 track points when the max distance fed into the algorithm is set to 10 metres. This is the default setting on my website (which indeed uses that algorithm plus the radial distance algorithm) for simplifying tracks.


telstarbox

  • Loving the lanes
Re: Should I include controls in GPS file?
« Reply #24 on: September 04, 2017, 04:06:01 pm »
Right, think I've sorted it. Many thanks all.

The GPX file below contains five "hand-written" waypoints with a unique 6-letter name, inserted between the metadata and the TRK section (which is generated from Strava). If anyone could double check this I'd be much obliged.

https://drive.google.com/open?id=0B9N-QE1V7uI4eUxNVUx6UzNTQW8
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