GPS Caveats

For every bit of technology (or rather for every activity that is based on technology) I like to have a plan "B". 

In my case that's going to be an iPhone 5s with or without a SIM card (given the Hazards recently encountered I think that might well be with). This provides me with a plan "B" for GPS, Camera, Kindle and iPod in one neat package.

Time was when I had no technology of any sort. Sigh! Do as you wish of course.

Here are some additional caveats specific to GPS which I've learnt over the last few years.

Some GriPeS

Once again I used my Garmin eTrex 20. The more I use this bit of kit the more the crappy software and sloppy interface annoy me. That said it sort of does most of the job with a few significant gripes. 

On the plus side
It is small, quite light, sufficiently waterproof and robust. Battery life is good and running costs low.

On the down side

• One major irritation is that it frequently loses the destination that it is navigating to. Then I have to repeat finding and choosing the same destination again.
• It does this after about 30% of power cycles (off/on). I am not sure what triggers this and the latest firmware has not fixed it.
• If it doesn’t lose the destination it instead tells me that I am arriving at it - even when I am many kilometres away.
• Waypoints often fail to save. 
• Garmin customer service is notoriously poor, but have they never actually used one of their products in the wild? How would anyone let this go out the door as a finished product.

As I’m increasingly suspicious of the way it works (or not). Out of caution I now do the following

• I only have one map enabled at a time. This may also speed up boot times which are often very slow.I only have one Track showing on the map at a time. 
• As I near the end of one Track I set it to Hide on Map (or Archive) and only then set Show on Map for the next Track.
• I only save a waypoint where I sleep. And even then I have to check that it actually saved. This is a nuisance.
• When I save a waypoint I use only the default name (a number).
  If I rename the waypoint it does not save. If a create a waypoint from a place on the map it does not save. Yes, it appears to, but one reboot later and it is gone. A real pain.

In summary
All these irritations aside it does in fact do the rather few things I now demand of it tolerably well. It does them in the dark and in any weather. When later on I look at my google map (in satellite view) I find that a waypoint I have recorded is smack bang in the centre of the building where I recorded it. That’s more than accurate enough for me.

It doesn’t weigh much and consumes AA batteries quite slowly in the usage pattern I employ (on for about 30-60 times a day for 1-2 minutes each time - so from 30 mins to 2 hours per day). 

And the cost is modest compared to paper maps given that my ongoing map costs are now zero. 

However as a device it is looking expensive compared to a smartphone when you consider the level of overall functionality. High time for Garmin to raise their game by about 1,000%.

Other caveats

• Amongst other limitations, imported Tracks can only contain 500 points even though you can have up to 10,000 points on a recorded Track.If this irritates you then ask Garmin why they needlessly do this. It may be due to memory constraints on the device.
• I put all 14 Tracks into a single GPX file. I suspect that perhaps it is better to have only one Track per file, though I have found nothing that says I must do this.
• In any case I have found that it is vital to have a backup of all my data on a Micro SD card with me. On this card the GPX file(s) should also be in the /Garmin/GPX directory. Otherwise they will not be visible to the GPS.This backup enabled me to get a new working copy of a Track that had failed. See below for details.
• Consider changing the names (those within the GPX file, not the filename) of all these Tracks so that it is clear that they come from the backup copy.
• I always have two sets of spare AA batteries. Just in case I fail to turn off the device one day and suddenly a whole set is gone. Or I meet someone in desperate need.

When a Track fails to display

• I was using the device without the Micro SD card installed.
• One of the Tracks suddenly did not display on the map.
• It remains visible in the list of Tracks in Track Manager.I suspect that this occurred when I was displaying more than one Track at a time from the same GPX file. But I can’t be sure.
• So now it cannot be used or deleted or archived.You can in fact delete the file using a computer, but of course you don’t walk trails with one. Looked at later on a computer the files were corrupted. The culprit for this has to be poor Garmin code, of which there is far too much.

On the GPS

• Insert the micro SD card with your backup tracks and restart the device.
• In Track Manager you will now see two copies of each Track. 
• One of these is on the device the other on the card.Don’t expect the Garmin software to be smart enough to show you which is which. That’d be asking too much. However if you were very cunning you would have anticipated this and changed the names inside the backup GPX files ahead of time. 
• Pick the one you need and if it works it’s the right one. If it does nothing it is the one you will need to delete later.
• Select the Track and use the option Copy Reversed. 
• This copies the Track (with a new name) from the card to the device.
• Remove the card.
• Now in Track manager you will see the new Track name and can use it, including display it on the map.It does not matter that it is reversed, at least to me, as I never “follow” (in the GPS sense) a Track. I merely walk along it.
• Once I had figured out this trick I repeated it for all the tracks ahead of time. This saved me having to stop and fiddle around in the middle of the walk.

In future

• I would create separate GPX files for each track and also load a copy of each track under a different name (For Example SNT-S01 and SNT-R01). Then only display one track on the GPS at a time.
• Irritatingly the GPS sorts the tracks based on the distance to the start and does not offer an alphabetic sort order.I named my tracks SNT-S01, SNT-S02 ... SNT-S14. Each of my sections contained the next 500 track points and covered several of the Stages as defined in the notes.