producing gpx track for audax perm by gps

[trickedem]

I have a Garmin 800 which I use for navigation and tracking my rides. I am happy with it, although it has its faults. on the 400 I did recently it worked fine to get me round the course, but I lost park of the track.


So I have been considering a cheap back up option, that I would simply use to produce a gpx track of where I had been. I have looked at a few possibilities:

http://www.emacberry.com/gpslogger.html         running on a blackberry

http://gpswebshop.com/IGotU_GT-120GPS_Logger.html         stand alone device

or an earlier model etrex from eBay, which would cost around £50

I would be interested in hearing your views on this.

[Somnolent]

My guess. and it is only a guess, is that the Blackberry option would have insufficient battery life for anything beyond a 200

[frankly frankie]

No personal experience, but something like this?
http://www.holux.com/JCore/en/products/products_list.jsp?pno=2

Or you can find similar buit in to a bicycle back light this - but looks defunct

For proof of passage purposes you only need very 'approximate' tracking - say once per 5 or 10 minutes (as opposed to normal GPS which is more like every 5 secs).  So in theory something very small and light with a silver cell as power should suffice.  Though it needs a decent sky view (not in the bottom of the saddlebag).

[phil d]

No personal experience, but something like this?
http://www.holux.com/JCore/en/products/products_list.jsp?pno=2

Or you can find similar buit in to a bicycle back light this - but looks defunct

For proof of passage purposes you only need very 'approximate' tracking - say once per 5 or 10 minutes (as opposed to normal GPS which is more like every 5 secs).  So in theory something very small and light with a silver cell as power should suffice.  Though it needs a decent sky view (not in the bottom of the saddlebag).

I tried a Holux (241c) as a backup for recording a GPS DIY.  I could not get a tracklog out of it that would be any use for verification - no altitude data on the log.  The manual is pretty useless (very cursory translation from the chinese).  It did claim to be logging altitude, but I just could not extract the information.  I could however extract time and place data.

I gave it away.  I suspect the recipient has now thrown it away!

[wajcgac]

I have this logger GPS logger and this battery pack Battery pack

Total cost about £35

I currently have 700km/35 hrs of rides stored which has used 16% of logger memory.

This battery will last an estimated 75hrs.

Logging seems to be very reliable, and it works at bottom of saddle bag.

Altitude data from it is not reliable but I think this is true of many GPS units without an altimeter?.

You need the supplied software to be installed to be able to get the data from it. The software on the disc supplied was out of date but you could still export the GPX track from the logger to your pc and view with 3rd party software/web page.

You can download the updated software to solve this problem from here

http://download.itravel-tech.com/SJA/20120329_SJA/gpsPhotoTagger_install_sja_pro.exe

I haven't submitted a route from this for DIY validation yet but hope to in the next couple of weeks.

[trickedem]

I have this logger GPS logger and this battery pack Battery pack

Total cost about £35

Thanks, this looks just  the sort of thing I am after. I have ordered from Dealextreme and the cost is so low, I feel like I don't have much to lose.

[Ian H]

Steve independently checks any submitted route for AAA-worthiness, so accuracy in that department is not essential.

The main thing you need for gps validation is an unmodified gpx track. Gps Visualiser will convert tcx and some other files without rendering them useless for validation.

[wajcgac]

Ian H mentioned any submitted route is checked independently for AAA worthiness anyway which is useful to know.

I also like to import the gpx track from the GPS logger to Memory Map 2004 where I can see how much climbing I have done even though I might not be claiming any AAA pts.

However to do this I have to upload the gpx file from the logger to GPS Visualizer and get it to convert it to a gpx file and then it will import successfully in to Memory Map.

This seems  a little strange but may be someone with greater knowledge of gpx files could explain?

[frankly frankie]

I think it's just that GPX is a very precisely-defined format and programs vary in how fussy they are if there is any divergence from the exact correct format.  Similar to the way different browsers react to non-compliant html code.
Memory map is actually more tolerant of mal-formed files than some - Garmin's own Mapsource program can be very fussy indeed. 
The nuts and bolts behind GPS Vizualizer (it's a simple web front end for GPS Babel, which you can also install as a desktop program but it's a bit un-friendly) is very good at taking 'incorrect' GPX files and rewriting them more 'correctly'.  It's a very useful resource.

[wajcgac]

My first DIY by GPS using this GPS Logger has been passed as OK.

So for anyone looking at being able to do DIY by GPS on the cheap or who just needs a back up to their main unit, then this powered by a battery pack of your choice offers great value.

[frankly frankie]

Looks interesting.  Does it, in fact, record elevation data?  (The page you linked kinda suggests not.)

(It's not a question of AAA-worthiness, but simply that AUK's validation tool needs elevation data to work properly, regardless of whether the route was hilly or not.)

[wajcgac]

As you say it doesn't mention recording altitude data on the description but I can confirm that altitude data is indeed recorded  - but it is not very accurate.

On the 300k ride I've just had passed as ok, the route when plotted on memory map showed significantly less climbing than that recorded by the GPS unit.

I'm wondering why altitude data (even if inaccurate) is required if you are not claiming AAA pts or if the route is independently checked for AAA worthiness by the DIY organiser?

[frankly frankie]

It's just the way the validation widget works - among other things it checks that the riding speed throughout the track is roughly consistent with the gradient.  If it isn't, that just alerts the person validating to maybe take a closer look at the GPX file.  The data doesn't have to be particularly accurate for this to work.