Author Topic: Using tracklogs to validate DIY perms  (Read 44897 times)

DanialW

Using tracklogs to validate DIY perms
« on: August 19, 2009, 12:56:25 pm »
I'm taking a proposal to the next commitee meeting, to allow me to test using tracklogs and GPX files to check and validate DIY perms on my patch. I hope that the commitee will allow me a temporary waiver to validate rides without the normal proof of passage, such as stamps and receipts.

If the committee are amenable, how do you see such a system developing?

My first thought is that the shortest distance between controls needn't apply, as the route ridden will be clear to see. How to might I be reasonably confident that the rider rode the route? I don't think there will be issues with forged tracklogs, but how might I guard against such nefarious deeds?

Any thoughts gratefully welcome. Any volunteers to experiment on also happily considered.

Re: Using tracklogs to validate DIY perms
« Reply #1 on: August 19, 2009, 01:47:16 pm »
I think you would still need some 'traditional' proofs of passage. I can't imagine why someone would want to commit audax-fraud, but it is fairly straightforward to take an existing gps track and just change the dates on the track points.

But with a gps track it should be possible to require less receipts etc, and distance verification will be much easier, and result in less disputes


Re: Using tracklogs to validate DIY perms
« Reply #2 on: August 19, 2009, 01:47:53 pm »
My first thought is that the shortest distance between controls needn't apply, as the route ridden will be clear to see. How to might I be reasonably confident that the rider rode the route? I don't think there will be issues with forged tracklogs, but how might I guard against such nefarious deeds?

As a computery guy rather than someone who knows about Audax:  It'd be pretty trivial for anyone competent to forge a single gpx file. 

I know there's no reason for tough security, but maybe asking just a couple of receipts for the whole ride (which match up with the tracklog) might be cautious?  Just a single something/anything more than the tracklog alone. 

Then it's surely worth the fairer distance/easier planning benefits.


DanialW

Re: Using tracklogs to validate DIY perms
« Reply #3 on: August 19, 2009, 01:50:21 pm »
It's a good point you two make. I did wonder if there was potential to use, say MS Excel to check two ostensibly identical tracklogs to make sure they were sufficiently different in terms of geolocation, gaps bewtween points, etc.

Re: Using tracklogs to validate DIY perms
« Reply #4 on: August 19, 2009, 01:52:04 pm »
My first thought is that the shortest distance between controls needn't apply, as the route ridden will be clear to see. How to might I be reasonably confident that the rider rode the route? I don't think there will be issues with forged tracklogs, but how might I guard against such nefarious deeds?

As a computery guy rather than someone who knows about Audax:  It'd be pretty trivial for anyone competent to forge a single gpx file. 

I know there's no reason for tough security, but maybe asking just a couple of receipts for the whole ride (which match up with the tracklog) might be cautious?  Just a single something/anything more than the tracklog alone. 

Then it's surely worth the fairer distance/easier planning benefits.


I can't imagine it would be much effort to completely fabricate a gpx in much less time it takes to go out and gather receipts using some other means than human muscular effort.

red marley

Re: Using tracklogs to validate DIY perms
« Reply #5 on: August 19, 2009, 01:58:10 pm »
Excellent Danial. Good luck with the proposal.

I suggested this on the AUK list a few years ago and was met with a whole list of ways in which GPS-related proof of passage could be forged. Of course it could. But so could more conventional means. The whole system is built on trust anyway. For example, use of Info controls on perms, manual annotation of receipts where the till time is wrong or has no indication of the location, using postmarks on postcards, the fact I can get Fixed Wheel Points for a perm that no-one else witnesses etc. etc.

Long may we continue to rely on trust, and lets not put new methods of route identification under greater scrutiny than older ones.

Re: Using tracklogs to validate DIY perms
« Reply #6 on: August 19, 2009, 01:59:32 pm »
I've also had problems with the GPS turning itself off, either due to rattling or old batteries of duff rechargeables. I don't always notice either, especially if I'm going over familiar roads where I don't need the GPS for direction.

Saying that, it would certainly make it easier to ride DIYs along nicer routes. There are times when I've had to miss out on certain roads/routes purely because of a lack of an appropriate control on one section. Being able to rely on the GPX for proof of passage for some subsections (not even all of the ride) would be very useful.

It would also make convoluted routes much easier. For example, I'd like to be able to do the Surrey Hills route as a detour from home to work (or vice versa) as a DIY 100. It's possible to DIY it, but it means compromising the route.

http://www.bikely.com/maps/bike-path/167493

The problem is the lack of anything useful in Ewhurst. There's a pub but I'd be looking to do this early in the morning when it won't be open. I can DIY it by moving the control to Cranleigh but that pulls me off the route that I want to take.

Being able to use normal controls (Putney, Epsom, Dorking, Epsom, Putney or Waterloo) with the GPX file for Ewhurst would solve this problem.
"Yes please" said Squirrel "biscuits are our favourite things."

Re: Using tracklogs to validate DIY perms
« Reply #7 on: August 19, 2009, 02:00:10 pm »
I'd have thought that it's better evidence than the current method. At present, someone could drive between the controls and hang around long enough at each to make it convincing - you'd never know they weren't on a bike. Presumably the GPS log would reveal average speeds attained at various points? If so a cheat would have to be very careful to drive in such a way as to mimic a bike - so much so it would probably be more trouble than it's worth. Actually, I'm struggling to think of a way of cheating that's less detectable using a GPS than with the current system.

Freedom from having to faff about finding proof of passage at particular locations would certainly encourage me to have a go at DIY's.

Edit just read the above posts about forging the GPX file entirely, never thought about that. Wouldn't it be a pain to make it look convincingly cycle like?

Re: Using tracklogs to validate DIY perms
« Reply #8 on: August 19, 2009, 02:01:37 pm »
It's a good point you two make. I did wonder if there was potential to use, say MS Excel to check two ostensibly identical tracklogs to make sure they were sufficiently different in terms of geolocation, gaps bewtween points, etc.

I wouldn't personally bother - down this road lies a technical tit-for-tat improvement in checking and falsifying gpx files.  Ask for something real-world instead to make it less appealing to the inner geek to try it.

I can't imagine it would be much effort to completely fabricate a gpx in much less time it takes to go out and gather receipts using some other means than human muscular effort.

For the first one, yes, but once the script is written... 

I'm just suggesting requesting a single something else to be cautious really.

Re: Using tracklogs to validate DIY perms
« Reply #9 on: August 19, 2009, 02:02:34 pm »
I presume you'll still need an entry form with minimum distances calculated using Autoroute or ViaMichelin ? What if the tracklog is shorter than the approved entry ? I presume it'll be ignored and only the time of passage considered ?

mattc

  • n.b. have grown beard since photo taken
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Re: Using tracklogs to validate DIY perms
« Reply #10 on: August 19, 2009, 02:03:30 pm »
If the 'shortest route' concept is ditched, will you still have controls?

Will riders still submit their route in advance? How closely will you check that the route they ride is the same that they submitted?

If they go off route, do they have to return to their first deviation? Or just ride far enough to make up the distance? What about road closures?
Has never ridden RAAM
---------
No.11  Because of the great host of those who dislike the least appearance of "swank " when they travel the roads and lanes. - From Kuklos' 39 Articles

Re: Using tracklogs to validate DIY perms
« Reply #11 on: August 19, 2009, 02:04:39 pm »
If the 'shortest route' concept is ditched, will you still have controls?

Will riders still submit their route in advance? How closely will you check that the route they ride is the same that they submitted?

If they go off route, do they have to return to their first deviation? Or just ride far enough to make up the distance? What about road closures?

CUrrently we just submit a list of controls and distances with the entry form, no route. This can't change surely ?

DanialW

Re: Using tracklogs to validate DIY perms
« Reply #12 on: August 19, 2009, 02:05:05 pm »
Being able to use normal controls (Putney, Epsom, Dorking, Epsom, Putney or Waterloo) with the GPX file for Ewhurst would solve this problem.

What an excellent suggestion. I'd never thought of this.

DanialW

Re: Using tracklogs to validate DIY perms
« Reply #13 on: August 19, 2009, 02:07:12 pm »
If the 'shortest route' concept is ditched, will you still have controls?

Theoretically, no. The route is the route. The downside would be a lack of freedom to improvise as you go along, which a control-based system affords you.

Personally, I favour a control-based system, but I'm willing to have my head turned.

Re: Using tracklogs to validate DIY perms
« Reply #14 on: August 19, 2009, 02:07:17 pm »
Actually, I'm struggling to think of a way of cheating that's less detectable using a GPS than with the current system.

I could create a realistic fake GPX tracklog without having to get off my chair, let alone drive around a route in a car collecting receipts.

All I'd need to do is take a tracklog of a route created on bikehike and apply some semi-realistic error to it (I know what kind of error to add as I've compared many tracklogs to actual GPX logs). Then I'd write something to fake the timestamps based on a bunch of variable parameters. With a bit more work I could also create a program that could take the tracklog and create any number of gpx tracklogs for realistic "rides", I can add my own simulation of wind, tiredness, random delays for punctures/stops, etc to make each one different.

Mind you, it's still quite a lot of work when I'd rather be out riding the bike.

I'm with jwo. It's highly unlikely that someone would go to all that effort to fake it, so why bother worrying about it. And if they do then more fool them.
"Yes please" said Squirrel "biscuits are our favourite things."

Re: Using tracklogs to validate DIY perms
« Reply #15 on: August 19, 2009, 02:08:56 pm »
If the 'shortest route' concept is ditched, will you still have controls?

Theoretically, no. The route is the route. The downside would be a lack of freedom to improvise as you go along, which a control-based system affords you.

Personally, I favour a control-based system, but I'm willing to have my head turned.

so the entry form would simply say "on Monday 28th I'm going to ride 207km " ?

frankly frankie

  • I kid you not
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Re: Using tracklogs to validate DIY perms
« Reply #16 on: August 19, 2009, 02:10:12 pm »
I wouldn't want a gpx file to be anything other than the plain text file it is, but it is rather unfortunate that there is no embedding of the GPS Id in the file, similar to the way the camera info is embedded in a Jpeg.

I think forging a convincing track from scratch might be quite challenging (even if it seems simple to some people here) - however copying and re-dating an existing (ridden by someone else) track is very easy.  So I think you need a hardcopy proof of passage at the furthest point of the ride, at least.  But with that in hand, I don't see so much problem with the rest of it.

Your point about the shortest distance thing would be a real plus, and I feel sure might help sell it to committee who otherwise might be expected to let their inner luddites out for a run, on a proposal like this.
It's not dark yet but it's getting there.

DanialW

Re: Using tracklogs to validate DIY perms
« Reply #17 on: August 19, 2009, 02:10:19 pm »
I'm with jwo. It's highly unlikely that someone would go to all that effort to fake it, so why bother worrying about it. And if they do then more fool them.

FranklyFrankie made the point that wireless GPS units may be able to send tracks to each other in the future, which may make the vlidation of gpx files during events a bit trickier.

But for now, I'm going to pilot this, committee permitting on DIY/Mesh routes. And indeed, more fool you if you're prepared to forge one.

red marley

Re: Using tracklogs to validate DIY perms
« Reply #18 on: August 19, 2009, 02:10:58 pm »
As a computery guy rather than someone who knows about Audax[...]

Let's not get carried away with speculating about how such things could be forged. As both a computery guy and someone who does Audax, the main point to me is that I have absolutely no desire or reason to forge a DIY route. There is no point. My inner geek has no trouble in seeing that such a thing could be forged, but that doesn't mean anyone would actually do so.

As for Matt's point about controls, you could still keep the same rules about controls (max distance between them, nominal min and max times to arrive at them etc.). It's just that proof that you get to those controls at a given time would be via the tracklog, not a receipt. Nothing to stop you going off route, following road diversions etc. just like we do at the moment, as long as you do arrive at the pre-agreed controls within time.

DanialW

Re: Using tracklogs to validate DIY perms
« Reply #19 on: August 19, 2009, 02:11:55 pm »
so the entry form would simply say "on Monday 28th I'm going to ride 207km " ?

Not quite. It might say "I'm going to rie 207km, and here is the route as a gpx that I made on memory map/bikely/wherever.

Re: Using tracklogs to validate DIY perms
« Reply #20 on: August 19, 2009, 02:13:11 pm »
As for Matt's point about controls, you could still keep the same rules about controls (max distance between them, nominal min and max times to arrive at them etc.). It's just that proof that you get to those controls at a given time would be via the tracklog, not a receipt. Nothing to stop you going off route, following road diversions etc. just like we do at the moment, as long as you do arrive at the pre-agreed controls within time.
But that doesn't tally with what Danial just said. No pre agreed controls, just a route. I am warming to the idea of not having to ride roughly 10% more to satisfy the agreed route. All I need now is someone to make a GPS that is tiny and will record my path without having to sit on my handle bars and get in the way. Don't need it to tell me where to go.

DanialW

Re: Using tracklogs to validate DIY perms
« Reply #21 on: August 19, 2009, 02:14:53 pm »
As for Matt's point about controls, you could still keep the same rules about controls (max distance between them, nominal min and max times to arrive at them etc.). It's just that proof that you get to those controls at a given time would be via the tracklog, not a receipt. Nothing to stop you going off route, following road diversions etc. just like we do at the moment, as long as you do arrive at the pre-agreed controls within time.
But that doesn't tally with what Danial just said.

I see this as a thrasharound of ideas. I've no fixed proposal yet, as nothing's been tested or really thought through thoroughly.

red marley

Re: Using tracklogs to validate DIY perms
« Reply #22 on: August 19, 2009, 02:17:01 pm »
As for Matt's point about controls, you could still keep the same rules about controls (max distance between them, nominal min and max times to arrive at them etc.). It's just that proof that you get to those controls at a given time would be via the tracklog, not a receipt. Nothing to stop you going off route, following road diversions etc. just like we do at the moment, as long as you do arrive at the pre-agreed controls within time.
But that doesn't tally with what Danial just said.

True - that's rapid cross-posting for you.

My personal opinion is that getting points for 200km of tracklog, do be decided on the day is not quite in the spirit of Audax. I think part of the challenge is have a pre-defined route that you are obliged to follow, overcoming weather and other difficulties to complete it.

The Mile-eater Award (note, based completely on trust) is the one for people who just want to get credit for the kms.

DanialW

Re: Using tracklogs to validate DIY perms
« Reply #23 on: August 19, 2009, 02:19:42 pm »
I think there has to be a pre-defined route, be it defined by controls or a fixed route.

I'll wager there are insurance implications in ensuring that as a minimum.

Re: Using tracklogs to validate DIY perms
« Reply #24 on: August 19, 2009, 02:21:22 pm »
FranklyFrankie made the point that wireless GPS units may be able to send tracks to each other in the future, which may make the vlidation of gpx files during events a bit trickier.

Spotting identical gpx tracklogs is trivial. It's no different to the fact that receipts from petrol stations/ATMs can be photocopied and submitted by another rider. If looked for it would be obvious that they were duplicates.

Even two identical GPS devices, similarly configured, running side by side on the handlebars of the same bike will produce quite different tracklogs. It would even be pretty much impossible for anyone to determine whether two such GPX files were the result of one rider with two GPSes, or two riders on separate bikes who just happened to ride close to each other for the entire ride.
"Yes please" said Squirrel "biscuits are our favourite things."