Here are my final conclusions and practices using GPS navigation on the trail- for what they are worth. I have spent the last few weekends trialing the bike and the GPS in the back-country here on my doorstep. Riding on formal gravel roads with culverts and signposts through to high altitude tracks scraped by a bulldozer some 20 years ago.
Bike – DR650SE
GPS – Garmin etrex Vista Cx with Topo’s preloaded
Mapping – PC version - Memory Map Manager (MM) for GPS Navigation, Version 5.1.3 Build 715 with South Island topos, street maps and Landsat images
Rider – Old Fart who should know better!
1) GPS loaded topo’s are a waste of space and money – astride the bike in a howling nor wester peering into the piddly little screen it was impossible to gain any perspective or overview of my location. I rarely use the map on the GPS at all now. I take printouts of maps/routes from MM.
2) Preloaded points of interest (POI) and Routes are the way to go (pun intended). I develop these in MM, where I mark out and modify the map either as complete routes with waypoints or POI’s for later navigation on the trail. The GPS is loaded with these prior to setting out and a track & map printout stuffed into my backpack.
3) The GPS is set to Trip Manager or Compass on the route – it then points to the next waypoint on the Route, giving Time/Distance readouts and if you want it, Track Error and a blizzard of other information for techo-heads like me.
4) Proximity alarms can be setup for key waypoints – those that require more attention such as turns, or interesting areas – this has proven invaluable – I can hear the plaintive bleep bleep from the Garmin even over the bike’s exhaust and the Nor Wester!
5) The Garmin autologs the Track – this is the real-world track followed as distinct from the Route, which is theoretical. Auto Track can be set for distance or time tracking – on the golf course I set it to 2M and obtained a very high resolution track of the nine holes. Out on the trail 50M is fine. More resolution means more memory used – eventually the Garmin will over write the Track on a First in First Out basis.
6) Uploading the Track into MM at home over a beer I compare and update the Route for later reuse, adding in gates, fords, bogs etc – stuff that is not shown on the maps.
7) Tracking allows me to deviate from the planned route and explore areas not marked, tracking back to my Route when I’ve completed the diversion.
8) The Garmin provides for Reverse Route or Tracking – I got into a bog on the tops and decided to go back – road tyres (knobblies haven’t arrived yet) and on my own – reverse routed the Garmin and it back tracked me home.
9) Accuracy – bloody good – and comparing the Track to the MM Topo showed excellent accuracy also – I POI’d a track over Clyde way and navigated to it – couldn’t see anything from the road junction but cut across the rough a bit and there it was – this has opened up new trails for me as I would never have noticed them otherwise.
10) POI’s can be added on the trail – this allows me to mark turns or other interesting features more accurately.
11) MM allows all added features (tracks, routes, POI …) to be emailed – so you can easily share routes or plan a trip – this is what I am presently doing for a Xmas trip into the Lammermoors.
12) Warning – any GPS is a sophisticated electronic device – you won’t be repairing it, even at home – if it fails or is damaged in a can off etc, you’re stuffed – add in some low cloud on the tops and a very indistinct trail and you're getting into a dangerous situation – make sure you have two GPS’s in the team and a selection of paper maps and ordinary compasses. Get to know how to use it all beforehand – it’s not an easy task on the trail and for real.
Summary – GPS is great fun, useful and allied with good paper maps, an essential device for off road trailing. By updating and maintaining your track and routes with local knowledge and trail experience a very comprehensive and useful navigationsystem can be had. Sharing MM information with fellow nutta’s is a nice feature.
Attachment pic shows ‘The Bike’ on the Old Woman Range – yeah I know, I should’a been on the Old Man Range (we have one!) – looking into the upper Nevis – eat ya heart out!!! Opppsss sorry – 45 16.138S, 169 03.368E @ 1724M
www.triginstruments.co.nz are the agents and where I bought my gear from - good sales service - a little tardy in getting back to inquiries.
Thanks for your comments - on reading my post back it reads like an ad for Garmin - not so - I knew bugger all about the practical aspects of GPS navigation and chose this unit on its ruggedness and versatility. Now I understand a little more and conclude that my purchase was a 'lucky guess' - although the $380 SD card topos was a mistake - the NZ freeware is just as useful.
Also - without MM it would be a daunting task entering waypoints etc from the map direcly into the Garmin - 20 key operations/waypoint with the fiddly little 'joystick' would drive me to drink ... none the less, some manual entries out on the trail will be necessary. MM is the key to my sanity. I will load waypoints for everything that looks interesting. Note - waypoints should be labelled 'meaningfully' - I've let MM label them (numbered system) and I've done a few myself and even limited to 6 digit/alphas it is better to do your own - seeing "WP0211 3" appearing on the screen means bugger all - "Fraser" means a lot more (hydro river near me).
Cheers for that Paul, I've always suspected that topomaps on an etrex size screen wouldn't be that flash. I've got Memory Map too, it's a bit more expensive than some but the street maps are really handy & other packages don't have 'em. I reckon a basic GPS & a mapping program for the PC to load up tracks is better value & more practical on a dirtbike than a big whiz-bang mapping GPS.
I may get an etrex legend if I upgrade from Dad's old Trimble. We're buying the father-in-law one for his b'day soon so I'll be able to have a play.
With BrentC's maps the Legend is capable of realtime navigation at 100kph, for road use it's sweet.
I'm looking for another Legend to replace mine when it dies.
Already had...
PC datacable wires vibrate off (all the time - I've removed them now)
Rubber grip gone - Insulation tape works well.
Backup battery vibrated off the GPS's motherboard but it still works.
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