Cheapest way to viewing gpx routes on tour without using your phone?

[Phil W]

For instance here is a trackpoint from the Round Netherlands GPX. Tell me what precsion those lat / lon and elevation are claiming. 

<trkpt lat="51.999610000000004" lon="5.466810000000001">
    <ele>19.000000000000004</ele>
   </trkpt>

I know it was a rhetorical question but I just looked up the answer anyway out of interest. Apparently, 13dp gives you angstrom levels of precision, so 15dp is going to be somewhat more precise than that.

https://gis.stackexchange.com/questions/8650/measuring-accuracy-of-latitude-and-longitude#8674

There are two points here that should not be conflated.

1) Number of track points,

2) Precision of the track points,

You can reduce the precision of the track points, I agree that 15dp is a bit overzealous 5 or 6 dp is plenty, however, the track point you have hilighted has come about due to a poor implementation in some software somewhere, of the IEEE 754 floating point standard. It's common in a lot of computer systems where designers don't know enough about the way their machine is storing the underlying bits. Many programmers look at a problem and think they will use floating point variables. Now they have 1.000000000000002 problems. This is why you can remove bloat from many a GPX, by simply taking all the values for lat/long, and making sure none of them are more than 5 or 6dp, (or even 3 or 4 if you're ok with 20+m of accuracy), this reduces the total number of bytes that the files needs to be stored. This can reduce the amount of CPU used by the device. However, as most programmers will just import the value into a variable, which will be either a 32bit, or in some cases (rare I'd say) 64bit, value, it takes the same amount of memory on the device to store 54.0, 54.123456 or 51.999610000000004, even if the actual file size for 54.0 is 14 bytes smaller. The only time that this longer variable then is slower than the shorter one is when it comes to reading the bytes off of the memory that the file is stored in, at which point you are looking at string manipulation, and saving yourself a couple of dozen or so clock cycles, when each clock cycle is done at many dozens of megahertz at least.

Thus, the precision of the lat/long points used in the gpx file, and the number of track points in the file, are two entirely separate things. I never claimed I needed angstrom level precision, and I hope that the above gives you an adequate explanation of why points like the above come about, and why it really doesn't matter, as well as how that is entirely not the point I am making.

So, having having dealt with that red herring, shall we move on to the issue of number of track points?

How about next time I go out for a longish ride, I upload my gpx file as it comes out of what ever route planner I've used, and one of you lot can reduce it to what ever you think is right, and I'll ride it, and we can see at which point I scream and switch to my original gpx[1]?

J

[1] Here, have Mondays ride: https://ridewithgps.com/routes/28119872 it's 1992 track points, 116km, give me a gpx with less than 116 points, and also tell me how long it took you to do it, and I'll see how far I get before it drives me too insane and I use the original route.

See my post at 1:11pm of actual etrex screen shots. You will not be able to tell the difference as the thousands of extra track points do nothing in terms of the track you see on your GPS. 

[Phil W]

Of course, why on earth would I leave it on chewing batteries whilst I stop for a bite to eat or to sleep?

So the overall average speed field is correct, presumably.

Seems a bit wasteful leaving the GPS running whilst I have a four hour sleep or even a 45 min eat.  Especially as you can get that stat if you load your data into any of the myriad applications out there.

[L CC]

I get QG's frustration, I really do. No one likes arriving 120km through a 400km ride and finding their pink line Just Ends. (Somewhere in East Anglia, for me. Back in 2010, maybe?)

Her response was to throw out the Etrex and buy something else. And her response now is to defend that choice through her own (limited) experience. N=1, and all that.

My response was work out how to use the GPS I had, properly.

There was much less choice then. I think the alternative was an Edge 800- we remember those, they were the ones with the random switch off at around 300km...

[Kim]

Of course, why on earth would I leave it on chewing batteries whilst I stop for a bite to eat or to sleep?

So the overall average speed field is correct, presumably.

Seems a bit wasteful leaving the GPS running whilst I have a four hour sleep or even a 45 min eat.

Wasteful of what?  A few electrons in a rechargeable battery?  I'm assuming this is an audax where you've planned your power budget accordingly, it would be daft for touring (which is why I habitually turn mine off, unless I'm only stopping for 5 minutes or so).

Especially as you can get that stat if you load your data into any of the myriad applications out there.

You can only do that sort of thing after the event, which isn't particularly useful.  If you keep the clock running, the 'overall average' field provides a realtime display of whether you're out of time or not during the ride.  *That's* the point.

Whether or not you find that useful enough to budget a little more battery life is up to you.

[L CC]

How about next time I go out for a longish ride, I upload my gpx file as it comes out of what ever route planner I've used, and one of you lot can reduce it to what ever you think is right, and I'll ride it, and we can see at which point I scream and switch to my original gpx[1]?

J

[1] Here, have Mondays ride: https://ridewithgps.com/routes/28119872 it's 1992 track points, 116km, give me a gpx with less than 116 points, and also tell me how long it took you to do it, and I'll see how far I get before it drives me too insane and I use the original route.

You can do it yourself. You'll only go wrong if you're a fuckwit. Here: https://simple-gpx.herokuapp.com/

I look forward to a post admitting your error.

I did BoB 1000km (That's Belgium- so cyclepaths and canalsides galore) on a Route with <500 points.

[Phil W]

Of course, why on earth would I leave it on chewing batteries whilst I stop for a bite to eat or to sleep?

So the overall average speed field is correct, presumably.

Seems a bit wasteful leaving the GPS running whilst I have a four hour sleep or even a 45 min eat.

Wasteful of what?  A few electrons in a rechargeable battery?  I'm assuming this is an audax where you've planned your power budget accordingly, it would be daft for touring (which is why I habitually turn mine off, unless I'm only stopping for 5 minutes or so).
Especially as you can get that stat if you load your data into any of the myriad applications out there.

Depends on whether you consider burning 20-25% of a battery's energy for no purpose a good thing to be doing. You do not need overall average for an audax. 

[Kim]

Of course, why on earth would I leave it on chewing batteries whilst I stop for a bite to eat or to sleep?

So the overall average speed field is correct, presumably.

Seems a bit wasteful leaving the GPS running whilst I have a four hour sleep or even a 45 min eat.

Wasteful of what?  A few electrons in a rechargeable battery?  I'm assuming this is an audax where you've planned your power budget accordingly, it would be daft for touring (which is why I habitually turn mine off, unless I'm only stopping for 5 minutes or so).
Especially as you can get that stat if you load your data into any of the myriad applications out there.

Depends on whether you consider burning 20-25% of a battery's energy for no purpose a good thing to be doing. You do not need overall average for an audax.

You do not need a GPS receiver for an audax.

You asked why someone would leave it on, I gave a possible reason.


ETA: Another reason, and one that I've actually kept my GPS switched on at audax controls for (I don't use the average speed display):  To keep an eye on what the time is.  Since I'm bringing the GPS receiver in with me so it doesn't get stolen, it can be useful to leave it switched on so I can see the clock while I'm eating/faffing.  Particularly if I've taken my glasses off to give my nose a sweat/pressure break and can't read the one on the wall.

[grams]

My app inserts *many more* points into every uploaded GPX file - LEL ends up as 78,000 points! It means elevation gets calculated properly*, navigation logic is simpler and *less* CPU intensive because all you're ever doing is looking for the nearest point rather than an imaginary point between two.

My £100 waterproof Android phone has no problem with this many points, and it downloads quickly enough and doesn't make a dent in the gigabytes of built-in storage, so however bloated or excessive this may be in theory, it has no practical effect.

(* As an extreme example, imagine a long, perfectly straight road with the same elevation at each end but a ridge of hills in the middle)

[fhills]

Right, you reduced it down to 10000. 10000 is still one way point on average every 167m. That seems reasonable. Thing is, the claim made above is that you shouldn't need more than 1 per km, so now take that gpx, and make it no more than 1670 points. Even then, that's more thanthe 250 that an etrex allows in a route.

You are still confusing routes and tracks. With routes, you need much fewer points. And in a route it is unhelpful if you have too many points.
If following a route, I want the GPS to display the "Distance to next". ie this should be the next place I have to turn off. If it says 1 km to the next point, it means I don't have to think about navigation until then, just keep following the road I am on. So it is pointless and confusing to have loads of extra points in between junctions, it just means you get the GPS beeping needlessly.

+ several.

I don't need to see a line following the road, even roughly. On a plotted ride the line is often not even visible on my screen though I can reassure myself that I am heading towards the next point by watching the "distance to" steadily decrease* and if especially nervous zoom out to see the line still there. As you say it is good to relax, ride the damn bike, enjoy the scenery, not peer at an algorithm all the time. Sometimes, so obvious is the road I am supposed to follow that the next point I have numbered may be 5 or even 8 km away. the geek IMHO should just relax and ride their bike more.

* sometimes, as when riding up and down inlets on a coastal road, the "distance to" may even increase for short periods, but since there is a sentient human being riding the bike there is no need for it to worry. Hell, you can read the landscape and let the Garmin get on with it.

edit - just checked a stored detailed GPX point to point of mine - from Peterborough (with a lot of twiddling getting out of town) to a London tube station - 169 points. Have ridden it. Despite my 4 pints en route, the Garmin's navigation was faultless.

[Cudzoziemiec]

Of course, why on earth would I leave it on chewing batteries whilst I stop for a bite to eat or to sleep?

So the overall average speed field is correct, presumably.

Seems a bit wasteful leaving the GPS running whilst I have a four hour sleep or even a 45 min eat.

Wasteful of what?  A few electrons in a rechargeable battery?  I'm assuming this is an audax where you've planned your power budget accordingly, it would be daft for touring (which is why I habitually turn mine off, unless I'm only stopping for 5 minutes or so).
Especially as you can get that stat if you load your data into any of the myriad applications out there.

Depends on whether you consider burning 20-25% of a battery's energy for no purpose a good thing to be doing. You do not need overall average for an audax.

You do not need a GPS receiver for an audax.

You asked why someone would leave it on, I gave a possible reason.


ETA: Another reason, and one that I've actually kept my GPS switched on at audax controls for (I don't use the average speed display):  To keep an eye on what the time is.  Since I'm bringing the GPS receiver in with me so it doesn't get stolen, it can be useful to leave it switched on so I can see the clock while I'm eating/faffing.  Particularly if I've taken my glasses off to give my nose a sweat/pressure break and can't read the one on the wall.

I do leave my GPS running at controls, precisely for the overall average speed display. I think one of the differences is that I don't ride audaxes with overnight stops, and neither, I think, does Kim, so it's only on and not moving for half an hour or so at a time.

ETA: If you are a more disciplined and/or faster audaxer, you won't need to keep an eye on your overall average anyway.

[frankly frankie]

The wahoo is not perfect, but it seems to be better than the Garmin's. It'll be interesting to see how many TCR riders this year are screwed over by Garmin failures...

Though what you (and they) might see as a Garmin failure I might regard as a user error ...

Frankie's claim above was for direct routing and he did not claim the route would follow the road, it won't. But he feels it is enough to navigate with if you place the route points only at turns. Not a method I have tried so cannot comment on how that would go for me.

Not only is it 'enough' to simply mark turns (generally) - but with direct routes less is more - any extra points between the turns simply cloud the issue and make the navigation less effective.

Regarding switching the GPS off at stops - it's unclear to me how much of a power hit the boot-up process is.  Even if it is 'hot-starting' ie after a short break of 15 minutes or so, on the Etrex there is still a lengthy process of importing all the GPX files into the GPS's own internal database.  This is repeated every time you boot.  (I think the Edges are different and probably better.)  For this reason on long tours (with GPX information to cover 2 or 3 weeks riding) I tend to leave the device switched on other than overnight stops or taking it indoors.  I still get 2 long days or 3 short days out of any pair of AAs (ie NiMH or alkaline - if lithiums 5-6 touring days is normal).

Regarding over-long co-ordinates - I have seen GPX files with 24 decimal points of 'precision' ... sub-molecular levels?  While accepting QGeek's point about these not impacting processing, they do go some way towards bloating file sizes.

Regarding the routes/tracks confusion and semantics - this RWGPS page linked on anther thread is a perfect example of my point:
https://ridewithgps.com/help/export-routes-to-garmin-device
their continued use of the word 'route' - while semantically correct for what they are trying to say, is extremely confusing when 90% of the time the end product they are directing you toward is a Track.  BikeHike are equally guilty of this.

[Samuel D]

Regarding the routes/tracks confusion and semantics - this RWGPS page linked on anther thread is a perfect example of my point:
https://ridewithgps.com/help/export-routes-to-garmin-device
their continued use of the word 'route' - while semantically correct for what they are trying to say, is extremely confusing when 90% of the time the end product they are directing you toward is a Track.  BikeHike are equally guilty of this.

I lay all of the blame for this at Garmin’s feet. Imagine a company like Apple or Google expecting users of mainstream products to apply such nuanced terminology. It’s insane.

[Kim]

The nuanced difference between memory and storage is beyond the average person.  It's not a terminology problem, so much as non-experts only having room in their brains for one class of list-of-coordinates data structure and regarding all terminology for such as synonyms, in the same way they treat all terminology for things-in-computers-that-hold-data as synonyms.

As I see it, there are two approaches to this sort of problem:  Either you educate your users so they can understand and apply the terminology effectively, or you abstract things in your UI to the point where they don't have to care about the difference.

Garmin are stuck with the 1990s approach where they explained how it worked in a manual, and users were expected to read and understand it in order to use the product.  Not only is this approach deeply unfashionable with modern tech users, but the art of writing manuals for consumer products declined sharply around the turn of the century.

Apple and to a lesser extent Google have made good money through the other approach.  It's still infuriating when they invent their own terms for things that there are perfectly good existing words for, but they're much less guilty of that than the Mega-Global Vendor Lock-In Corporation of Redmond, USAnia.


Frankly, it doesn't help that we - as long-distance cyclists - are trying to use these products in a way that evidently hasn't been given much, if any, consideration by the software developers.  When you're trying to creatively abuse a tool to do something it wasn't designed for, user-friendliness for the intended use-case is often unhelpful.

[Cudzoziemiec]

Is the root of the problem that originally, the record of where you have been was called a "tracklog", but that term has fallen out of use?

When I was new to GPS, I asked someone who'd been using it for years the difference between track and route.
"A route shows where you're going, a track shows where you've been."
"Okay, so for tomorrow's ride I need to put the gpx route on my Garmin."
"No, you need the track."
 ""

[Kim]

Is the root of the problem that originally, the record of where you have been was called a "tracklog", but that term has fallen out of use?

Not so much fallen out of use, so much that abusing the re-trace-a-recorded-track capability has become co-opted as the most practical (or at least user-friendly) way of getting a Garmin to stick to a planned, erm, [avoids ambiguous terminology] bike ride.

To the point where the current generation of Garmin users think that Tracks are synonymous with GPX files, and have little if any knowledge of Routes or even Waypoints.  A GPX file with a single Track in it has become a de-facto standard for sharing planned bike rides.

The Edge series muddy the waters with Courses (which, AIUI, are basically the same as Routes, but treated with the assumption that the objective is to follow the entire, erm, path, possibly multiple times - rather than just get to the other end).

[Cudzoziemiec]

It's a bit like cycle path, track and way, and possibly even lane. Especially when you consider that the historical "road-path" style of bike, which sounds like it should be a predecessor of cyclocross (or gravel, adventure, all-road, etc) bike, actually refers to a bike for road and, erm, track (in the velodrome sense). Terminology. Possibly even better than standards.

[Phil W]

Is the root of the problem that originally, the record of where you have been was called a "tracklog", but that term has fallen out of use?

The Edge series muddy the waters with Courses (which, AIUI, are basically the same as Routes, but treated with the assumption that the objective is to follow the entire, erm, path, possibly multiple times - rather than just get to the other end).

They were more of a hybrid of route and track. When creating them in Mapsource you could use auto routing to plot. The bit that was like a route. Plus you could add coursepoints for things like water, or turns.  There was a fixed set of the types of coursepoint you could add.  The course created acted more like a track however other than the prompts where you had placed your coursepoints.  The limit on my Edge 205 from 2004 was around 13,000 points in a course.  So not dissimilar to the 10,000 point limit of tracks in many devices today.  If you look inside the crs format files you will see the similarities.

[citoyen]

Terminology. Possibly even better than standards.

There's the rub. Although I think we can narrow it down further to that especially confusing subset of terminology: jargon.

But as long as you remember that 'Route' and 'Track' in this context bear no relation to their everyday meanings, you should be able to mitigate much of that confusion. I mean, I really don't care what the terms mean in Garminworld, and the historical reasons are interesting but not especially helpful. All I want to know is which type of GPX file is best for me to use for navigation on my audax rides. What they're called is unimportant.

[Cudzoziemiec]

Up to a point. It's important to remember which name as used in Garminworld or the world according to RWGPS, Bikehike, etc, corresponds to what you want, so you download the right file. But the reasons as to why it's called that are, as you say, jargon.

[frankly frankie]

Tracks and Routes are part of the GPX interchange standard and are nothing to do with Garmin.  And within that standard it is true, there is bugger-all difference between the two things, they each share the same set of possible attributes.  So on this basis, when an online Planner offers a choice between Track and Route, very often it is in fact offering the same file with just the 'trk' and 'rte' tagging substituted as appropriate.  So a 7165-point Track file (OK in most modern Garmins and other GPS) becomes a 7165-point Route file (broken in any GPS I know of).
Given that Phil W has just recently demonstrated how possible it is to do the job right (that is, intelligently downsampling as required) - then it's unfortunate the Planners fail to do likewise.

[fhills]

With regard to all those mega mega points forming a coloured road-following line on the gps map, don't folk find it tiring/find themselves peering at a screen rather the road all the time? Have never understood the point/attraction. As above I prefer minimal points, info on the distance to the next turn, and the turn marked.

[Kim]

With regard to all those mega mega points forming a coloured road-following line on the gps map, don't folk find it tiring/find themselves peering at a screen rather the road all the time?

You know when you get an OS map, mark a route in highlighter pen and put it in a bar bag?  It's like that without the stops to re-fold the map.  You don't have to peer at it all the time, just work out where the next junction is then re-check the map after the turn.  When you're turning from major to minor, it has the advantage that your own position is marked, so you don't have to obsessively count distance or check for suitable landmarks to work out which is the correct turn.

[citoyen]

peering at a screen rather the road all the time

This doesn’t describe my experience... which probably explains why I sometimes overshoot turns and have to double back when I notice a few hundred metres later - a problem that could be avoided but I hate devices beeping at me so I usually ride with the sound turned off.

If you’re using a device that supports proper turn by turn instructions, you still need to be looking at the screen to see the turn alerts, and/or have sound switched on to alert you (some people cite lack of sound as one of the shortcomings of the Karoo but I would consider it a blessing).

[grams]

Even without any alerts, you only ever need to glance at it at junctions. And if it can show a decent distance ahead you can get an idea where the next actual turn will be and can ignore it until then.]]

Although I often try to ride by my own senses (which is a fancy way of saying looking at signs or following others) and only glance at it occasionally to see if I'm on route or not.

[Cudzoziemiec]

I wonder if this preference for line on a screen vs turn by turn instructions reflects people who, before using GPS, were happiest following a map vs following a route sheet, respectively.