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Discussion Forum - Events - Winter Tanners

Author: Andy Carpenter
Posted: Thu 25th Jan 2018, 20:24
Joined: 2013
Local Group: Beds, Bucks and Northants
Both "Tracks" and "Routes" will work for navigation (for the unaware, they're different types of GPX files). Read on only if interested!!
A Route works by navigating you via a series of waypoints, with the Route's primary goal being to get you to the next one. A Track works by navigating you via a series of trackpoints, with the Track's primary goal being to keep you on the track. I appreciate that this difference sounds fairly minor (and in some ways it is!), but maybe the best way to think about it is what happens when you drift off-course:
- When off-course, a "Route" will auto-navigate you to the next waypoint (i.e. it'll straight-line you to there) - if you've got lots of waypoints, then this isn't too much of an issue, but devices often (not not always, before people cite the capabilities of their respective devices) can handle fewer waypoints than trackpoints, so this may not always be advisable when on technical (i.e. twisty & turny!) LDWA events.
- When off-course, a "Track" will try to get you back onto the track at the nearest point. This arguably may fit better with LDWA events, especially as it means getting back onto somewhere on the written route-description as soon as possible, rather than the device taking you straight to the next waypoint via who knows what terrain.
That said though, as Tim rightly says, using a Route enables you to set the audible alarm (which by the way is under the Marine settings coz - I think - it was originally designed to provide audible warning to sleeping sailors that their boat is drifting too far from its anchorage-point at night) for staying on course, whereas Tracks don't.
But, each to their own. Both have their own advantages and disadvantages, not to mention that the capabilities of modern devices are increasingly making the use of either method more viable than in the past.
Personally I prefer Tracks. They seem to lend themselves better to the idea of walking the route first in order that the event-organisers can record it and then ship it out to the entrants, in order to provide an exact course, as most devices (certainly mine) only seem to offer a save-option for Tracks not Routes.
Also, Routes will flood your device with Waypoints. Even if a device's capacity means this isn't a particular issue, it does create a housekeeping issue (unless you delete the lot each time). What I mean is, I like to record key waypoints and keep them on my machine indefinitely (e.g. my home, interesting specific locations, on often-visited summit, etc, etc), but it makes post-event housekeeping harder (at least on my device anyway) if I'm also having to try to avoid deleting the waypoints I want to keep. Tracks on the other hand can be easily and quickly loaded/saved/deleted without any impact on stored Waypoints.
It's all personal preference though, and software exists to convert between formats anyway. As long as we're out there doing it at all, that's the main thing!! :-)

Author: Tim Bedwell
Posted: Wed 24th Jan 2018, 22:47
Joined: 2016
Local Group: Surrey
Another option is to use Garmin Basecamp (free download) to convert the supplied track to a route. I have a Garmin eTrex 30x and you can use it to navigate a route, but only a maximum of 250 route points on that model. After converting the supplied track (30 mile) to a route in Basecamp, it came to just under 400 points, so I split it into two files, and switched to the second one half way around.
As well as being a lot less points, the advantage of using a route as opposed to using the track, is that the Garmin will give you an audible off-route alarm if you've set it up right, so you can follow the RD as normal, and only start to worry if the alarm goes off.
To set the alarm on the eTrex it's under Setup - Marine - Marine Alarm Setup - Off Course Alarm.
Why it's under Marine, I don't know - but fairly appropriate for the winter tanner's !

Author: Andy Carpenter
Posted: Tue 23rd Jan 2018, 14:37
Joined: 2013
Local Group: Beds, Bucks and Northants
No worries, Tony. Shout out if any more queries about GPX'y stuff, happy to help.

Author: Tony Cartwright
Posted: Tue 23rd Jan 2018, 12:45
Joined: 1978
Local Group: Surrey
Many thanks for your detailed feedback and suggestions Andy. Very helpful. I'll bear this in mind for next year!!

Author: Andy Carpenter
Posted: Tue 23rd Jan 2018, 0:36
Joined: 2013
Local Group: Beds, Bucks and Northants
Hi Tony.

The supplied GPX file
-------------------------------
It did seem to have some slightly odd characteristics - clearly some devices/software could handle it and some couldn't. I think one of the issues was the time-element stamped onto each of the trackpoints - it looked like the GPX had been constructed of several separate elements with different time/date stamps, all joined together. As I say, some systems won't care about this, but some devices will. Mine did, but once I'd stripped out the time-elements from the GPX-file, it worked just fine.

Future files
----------------
I agree with you, option 3 seems best - i.e. ship a file, and let people manipulate it as they see fit. Most modern devices will handle almost any number of trackpoints, but if people like me wanna stick to using old devices, it should be down to us not you to cope with this. (By the way, if you do decide to go down the minimum-size route, then choose 499 not 500. This will then work on all old Garmin devices, and I'm not personally aware of any other devices which can only handle an even smaller number than this.)

GPX Visualizer
----------------------
Here's how to reduce the trackpoint-count - only a few clicks required:
1. Select into "File#1" the GPX file you want to shrink.
2. Click on the "GPX" radio-button at the top of the box, to set the output-format.
3. Click on the "[+] show advanced options" green bar at the bottom.
4. Enter your required number of trackpoints into the "Max. points per track" box.
5. Whizz back up to the top and press the green "Convert" button.
You can then either copy-and-paste the results into a text-file of your own, else just press the "Click to download...." link, which will save the file to your Downloads directory, where you can then rename it as required.

Finally, you also asked about how the file-reduction actually works. Different systems use different algorithms for this, but it's generally not linear (i.e. to go from 400 to 200 trackpoints they wouldn't tend to simply remove every other point). They try to be more intelligent, looking both for sensible points to remove (e.g. as you rightly surmised, the less important points on long straights), but also looking for sensible points to keep (e.g. where there is an extreme change of direction, such as a sharp turn). It's never gonna be perfect, but to be fair they're pretty damned good at it. You can see this for yourself if you wish, by loading up both the original and reduced GPX files onto 1 map (GPSVisualizer lets you do this too - see MAKE A MAP), and you'll then see that the 2 routes as still virtually identical.
GPSVisualizer does other cool stuff too - for instance, if you have a GPX file that has no elevation data on it (or has elevation data on it that's just plain wrong, as many devices are notoriously poor at recording total ascent/descent correctly, for technical reasons I'll bore you with another time if interested!), you can overlay the correct elevation-data for that route onto the file.
Right's that's probably enough GPX fun'n'games for now!

Author: Michael Jones
Posted: Mon 22nd Jan 2018, 23:29
Joined: 2011
Local Group: Dorset
I think we can safely say that this year's event lived up to its billing of "tough winter walk" - anything which either the weather or the underfoot conditions could have thrown at us, they did! I like to think I can handle a certain amount of mud, but it becomes difficult to make reasonable progress when my boots can't get any traction - attempting to climb Box Hill, as soon as I put one foot higher up the slope it started sliding down again.

One of the few aspects of the event which didn't make things more difficult was the route description, which was excellent. I verge on the paranoid in this respect, always carrying a paper map and GPS (albeit this time without the GPX file, which had failed to load) in addition to the RD so I can check the three against each other in case of doubt - but yesterday neither the map nor the GPS was required. There was just one place where it might have been helpful to point out that the gate we were to take was hidden in the hedge; approaching what looked like a dead end made me wonder if I'd gone wrong at an earlier point. Getting over Box Hill was pot luck - if you can find anything which looks like a path, take it - but that was due to the poor visibility rather than any failing of the RD. The light at the bottom of the hill and the marshal guiding us on the descent were certainly helpful.

Many thanks to everyone involved in organising the event - and also to the fellow walker who found the glove I'd dropped at the start and reunited me with it a mile or so into the course!

Author: Tony Cartwright
Posted: Mon 22nd Jan 2018, 22:21
Joined: 1978
Local Group: Surrey
Andy,

I had a look at www.gpsvisualizer.com which looked interesting but could find no way of specifying the number of trackpoints in the conversion. I also wonder if it is a simple linear reduction or it takes out points where the track is straighter?

Author: Tony Cartwright
Posted: Mon 22nd Jan 2018, 22:08
Joined: 1978
Local Group: Surrey
Hi all,

Thanks for the comments - glad you 'enjoyed' it despite the conditions. We knew there would be mud (well this is the Winter Tanners) and as the date approached we did expect rain but not the snow that materialised. The event certainly lived up to its name this year - tough, and in no uncertain terms. A very well done to all who completed!

The Winter Tanners was the first time that Surrey has provided gpx files and I apologise to anyone that had problems loading them. I tracked the routes at an interval of 50m thinking this would give a appropriately accurate record, not thinking of the point count.. Over 40mi (64km) a track of over 1200 points resulted and from the comments it seems that it was this point count that caused the problem. We are keen to learn and it would be helpful to get feedback on what the gpx criteria should be. Options might include:-

1. provide a single track for each distance but with a max number of 500 points. So for a 40mi (64km) route this would require in an interval of about 130m. Maybe poor accuracy where paths are complex?
2. track at say 50m intervals to give the improved accuracy but split the route into segments of 500 points.
3. track at 50m with a single track and let individuals reduce the point count to satisfy their own needs/devices

For what its worth my own view would be for 3 - provide comprehensive data and let individuals manipulate it to suit.

Feedback would be welcome.

Author: Andy Carpenter
Posted: Mon 22nd Jan 2018, 21:20
Joined: 2013
Local Group: Beds, Bucks and Northants
Hi John. Don't know, I'm afraid. GPSBabel itself has a Help option which sends you to the user-guide on their website - whether it counts as simple is down to the reader I guess. :-)
Personally I only use it for shrinking GPX-files, so all I had to do was to learn to do that particular one feature of it, which I got sorted after a bit of trial and error.
An alternative is an online site called www.gpsvisualizer.com (so you don't even need to download a prog to your PC). It has a "CONVERT A FILE" option, into which you can upload your source GPX, tell it how many point-per-track you want (499 or whatever), then it'll generate a revised GPX. You may find this method more intuitive than GPSBabel.

Author: John Pennifold
Posted: Mon 22nd Jan 2018, 20:54
Joined: 1996
Local Group: London
Andy, is there a simple guide somewhere to using GPSBabel? I find the terminlogy & interface completely incomprehensible.

Author: Andy Carpenter
Posted: Mon 22nd Jan 2018, 20:32
Joined: 2013
Local Group: Beds, Bucks and Northants
For anyone interested, there are free programs you can download to your PC to manipulate GPX files. I'm sure there are others, but the one I use is called GPSBabel - this is a simple little utility which will run on virtually any computer (PC, Apple, etc) you may own, & has been around for over 15 years. It can do various things, but one of its most useful features is the ability to shrink a GPX file to whatever size you want. Like Paul below, I also use an old but trusty GPS device (it can only handle 499 trackpoints, so that's the size I shrink GPX-files down to). Obviously, the smaller a file is, the less accuracy it provides you with, but I've never had any problem navigating from a 499-trackpoint file, and it's only on the longer events like the 100 that I bother to split the supplied large file into maybe 3 or 4 files, in order to retain a tad more accuracy when then shrinking each of them down to 499. (NB: No, I don't work for GPSBabel, am just a user of it and am a keen GPX'er!)

Author: Paul Glynn
Posted: Mon 22nd Jan 2018, 17:30
Joined: 2015
Local Group: Wessex
Thanks to everyone who made this event happen, the tea & coffee at the last 2 CPs were unexpected but very welcome.

I too had problems loading the gpx file - for the 30 mile route. It contained so many waypoints that my trusty 5-year-old gps device would not load it. This made navigating the top of box hill in fog (5m visibility) and darkness a true challenge, but it would have been better to have a working gpx track as a get out of jail card.
Maybe one could be produced that has fewer waypoints?

Author: David Anthony Giles
Posted: Mon 22nd Jan 2018, 16:12
Joined: 1999
thanks to everyone involved with the Tanners yesterday, it was a memorable experience! check point staff must have been frozen so your time was very much appreciated

Author: Manfred Engler
Posted: Mon 22nd Jan 2018, 7:52
Joined: 2012
Local Group: Sussex
Hi,
thanks to all involved in planning and running this event. It was an experience!
Regards
Manfred

Author: David Wilson
Posted: Sun 21st Jan 2018, 21:11
Joined: 2016
Local Group: Thames Valley
Thanks to everyone involved in organising and running today's event!

Author: John Pennifold
Posted: Fri 19th Jan 2018, 22:19
Joined: 1996
Local Group: London
Iím sorry Tony, but Iím not sure quite what it is that I have Ďspoiledí? Itís not a thriller film or edge-of-the-seat book, itís just a walk. People know that on walks (or almost any activity), I take photos and make videos and publish them. Thatís what I do. Thatís all I have done in this case, along with some public information and private feedback.
I wasnít able to enter the event before it became full, and seeing as the route description and GPX file were provided, I took advantage of these and the excellent weather that was promised for Wednesday.
I must say that I enjoyed the walk, but itís a hard one and the conditions under foot are difficult. I realise that lots of hard work goes into the planning of the event and Iím sure that we all appreciate this. I canít see that my posts and photos have undone any of this good work. I was very lucky with the weather and I can see that the weather on this coming Sunday will make the walk very difficult for everybody; walkers & organisers alike. Iím not the sort of person who keeps information to myself; if I can help in any way then I do and this can include information thatís not available elsewhere. If my experiences can help others then why not? People will still encounter all the conditions for themselves, the dark, the rain, the mud, the getting lost, the cold, the early start, the late finish, the flickering head torch, the wet map, the welcoming checkpoint teams, the ambiguous RD, the low moments, the high moments, the euphoria of finishing; theyíll have all that. I havenít taken any of that away.
I did come across some issues on the walk and I have provided (in my opinion) positive feedback on these to the organisers. The feedback mostly related to the safety of walkers or farm animals or both. I have also volunteered to help out on the day if required.
I hope that everybody has a very enjoyable walk on Sunday.

Author: Tony Cartwright
Posted: Fri 19th Jan 2018, 18:40
Joined: 1978
Local Group: Surrey
Hi all,

The Winter Tanners is, and always has been, a tough winter event. It should be no surprise to anyone that stiles, cattle, gates, mud, deep mud, deeper mud, brambles, downed tress, flooded paths, electric fences, horses and anything else one might encounter walking in the countryside might well be found somewhere along the route(s) of the Winter Tanners. So no surprises there.

I have no problem with pre-walking the route but I do take exception to walking the route and reporting on it publicly before the event has even taken place. What drives this behaviour? A need to be 'first'? Hundreds of hours (yes literally hundreds) are spent devising the route and planning the event. Seems to me reporting on any aspect of it before it has even taken place is just a spoiler. Sad.

Author: John Pennifold
Posted: Thu 18th Jan 2018, 21:59
Joined: 1996
Local Group: London
Here are my photos of my solo round (yesterday) of the Winter Tanners 2018 - 40 miles.
Unfortunately it looks as if the weather on Sunday (for the real event) will be a little wetter.
https://www.flickr.com/photos/john_pp/albums/72157668620941349

Author: Neil Bromley
Posted: Thu 18th Jan 2018, 21:53
Joined: 2002
Local Group: Heart of England
Thanks for the advance warning, John. That's cheered me up no end! Think I'll wear galoshes.

Author: John Pennifold
Posted: Thu 18th Jan 2018, 15:32
Joined: 1996
Local Group: London
I walked the 40 mile route, solo, yesterday. It took me 15 hours 45 minutes.
I started walking at 05:15 and finished at 21:00. The weather was very nice; cold and windy but clear. There was frost for the first few hours with icy pavements & paths. I almost fell a couple of times. This melted later.
The first muddy section was the route parallel to the M25; even then my feet (in trail shoes) didn't actually get wet. The wet came later. There are many flat fields which are saturated with a thin skim of surface water. Traction was very difficult due to this for long periods.
The Route Description seems pretty good but I did get lost a couple of times. I carried a SatMap with the route loaded onto it. This saved me on a few occasions.
Bearing in mind that I started 90 minutes before Sundayís earliest start, I began to find that my time margin was getting tighter & tighter for clearing the closing times of checkpoints (allowing for those 90 minutes). I must admit that I took advantage of the only cafť on the route, ď52 The StreetĒ in Charlwood. I had a nice cheese & pickle sandwich and a cuppa; and I also warmed up!
I have to admit that I didnít manage the complete official route. At about 18:00, in the pitch dark, I entered a field of ankle-deep mud which showed obvious signs of cattle activity. The description said to cross seven long fields in a straight line crossing stiles. What with the dark, the mud, the possibility of encountering cattle in the dark, the impossibility of finding seven stiles in a row, and being all alone, I retreated and found a road detour to rejoin the route just before Box Hill.
Going on my total time, I wouldnít have completed the walk by the official finish time of 22:00. I would have been 30 minutes over. I am usually no slouch when it comes to walking. Last Friday I solo walked one of the old 30 mile Summer Tanners Marathons in 9 hours 20 minutes, but that was quite a dry route and there has been no rain since Friday, so I was really surprised by how wet the fields were on the WT40.
Best of luck everybody.

Author: Tim Bedwell
Posted: Thu 18th Jan 2018, 10:42
Joined: 2016
Local Group: Surrey
Hi John, I got it to work by renaming the downloaded file from .xml to .gpx. Link to it on osmaps is https://osmaps.ordnancesurvey.co.uk/route/1780539/40mi-Track

Author: John Pennifold
Posted: Tue 16th Jan 2018, 17:28
Joined: 1996
Local Group: London
I just downloaded the gpx file for the 40 mile route and imported it onto my SatMap.
I'm not sure what format it is but it created a folder called "WT18_40mi" within the "Internal Storage" folder and within this folder there was one file "WT18_40mi.gpx" of 109KB and 10 small files each of 1KB named "WT18_40mi1.gpx" to "WT18_40mi9.gpx".
The 'Routes' menu on the SatMap couldn't 'see' this file so it can't be activated. Using SatSync, I moved the larger file up into 'Internal Storage" (along with the usual .gpx files) but the 'Routes' menu still can't see it.
Looking at the raw file in Notepad++, it would appear that there are many waypoints "Wp 0001" to "Wp 0456" etc but this sequence repeats over and over.
Anybody else got this problem or know the fix?

Author: Mary Dee
Posted: Sun 24th Dec 2017, 10:10
Joined: 1984
Local Group: Surrey
Hi guys - now the route has been finalised please note the revised map requirements on the Surrey web site Looking forward to January - the underfoot conditions are coming along nicely - almost in prime condition!

Author: Mary Dee
Posted: Thu 30th Nov 2017, 14:30
Joined: 1984
Local Group: Surrey
This is a great event but it is filling up fast and is likely to fill soon. So if you're hoping to enter next year's Winter Tanners (21 January 2018) please get your entry in now. The mud is coming along nicely, but as for ice and snow ... we can only wait and see!

Author: Michael Jones
Posted: Sun 8th Oct 2017, 16:40
Joined: 2011
Local Group: Dorset
The Winter Tanners (30 mile route, 2012) was the first LDWA event I entered. I finished in (for me) a decent time, with only minor navigational errors, and I'm definitely not Bear Grylls, so I think I can safely say you don't have to be. Just bear in mind (no pun intended) that it is January, so i) it can be cold/windy/raining/snowing and ii) it gets dark early, so unless you're a runner or very fast walker, you'll need a torch. It isn't significantly more difficult than any other winter event of comparable length.

Author: Richard D Ireson
Posted: Mon 2nd Oct 2017, 11:09
Joined: 1977
Local Group: Surrey
The 40th Winter Tanners will be on 21st January at Leatherhead. To mark the 40th event we are adding a 40 mile route to the 20 and 30 mile routes. We have raised the entry limit to 500 and entry has now opened with 14% of the places being filled on the first day. LDWA members may wish to enter whilst places are still available.
Details are at https://www.ldwa.org.uk/Surrey/W/5100/winter-tanners.html
and entry is at
http://www.fabian4.co.uk/default.aspx?EventID=1854
We look forward to a great event

Author: John Pennifold
Posted: Fri 30th Jun 2017, 14:07
Joined: 1996
Local Group: London
I also saw a murmuration of rooks or jackdaws at sunset on the 2015 event https://www.youtube.com/watch?v=pM2V16uEPp4

Author: John Pennifold
Posted: Fri 30th Jun 2017, 6:59
Joined: 1996
Local Group: London
One often starts & finishes in the dark.Conditions could be anything from dry (unlikely) to thick mud to deep snow or anything else.
Here's a link to my photos from 2016 https://www.flickr.com/photos/john_pp/albums/72157662823637869
and another to those from 2015 https://www.flickr.com/photos/john_pp/albums/72157650291749672

Author: Louise Witt
Posted: Thu 29th Jun 2017, 22:29
Joined: 2016
Local Group: Dorset
Hello

Can anyone tell me anything about the Winter Tanners event please? I assume with the time of year it may be poor conditions but whats the actual event like? The write up says its tough with minimal support. Do you need to be Bear Grylls to get round?