GPS - The Myths and Truths - Part 2
GPS navigation systems for Walking and Hiking have their fans and detractors in seemingly equal measure.
Some think a GPS Device is just an unnecessary gadget for walking and hiking and used by overgrown schoolboys who would buy anything if it was yellow and had lots of buttons to press.
Others consider it to be a valuable navigational aid any serious walker should carry and learn how to use properly
Below we hope to address some the issues, myths and truths surrounding GPS Devices for Walking and Hiking – so you can make a value judgement on whether or not walking with a GPS Device is for you or not.
GPS Navigation Systems for Walking and Hiking
The Myths and Truths - Part 2
Myth: All a Walking and Hiking GPS naviagtion system is good for is to tell you where you are.
Truth: GPS navigation systems for Walking and Hiking do do this very very well, providing you can read and understand grid references* and have got the proper walking map with you. (Most GPS Devices for Walking and Hiking only give you a 10 digit grid reference - not a 'location' - like "Scafell Pike summit")
But a GPS Device will also tell you where you've been, how far you've walked, how fast you walked, what time the sun will set, what time the sun will rise, how far it is (in a straight line) to your chosen target (waypoint), how long it will take to get there at your current rate of progress and give a reasonable estimate of how high up you are.
You can mark a position that you might want to return to (which can be useful). You can follow your track to retrace your steps (which can be very useful if you lost something).
It will work in the car, if you're trying to find somebody's house, for instance.
You can even input a complete route, and it will lead you round it - but only if you have a GPS waypoints programmed in for every change of direction - which can be as many as seventy seperate waypoints for a typical mountain walk. In my experience, this 'walking by numbers' is rather soulless and not nearly as much fun as following a footpath and 'reading' the map and the scenery.
However - a GPS Device won't make the tea and is useless at keeping you warm.
Myth: GPS navigation systems aren't reliable and will let you down when you most need them.
Truth: This may be true of public transport sometimes, but not a GPS Device. It's true that a GPS navigation system does use a lot of battery power, but you do get a warning before it runs out. Make sure you carry a spare set of batteries (and just to be on the safe side - carry a 'spare' set of spares).
On a couple of occasions, my GPS Device has been unable to locate enough satellites, but only for a few minutes.
95% plus of the time, a GPS Device will lead you to within a few metres of a target.
Myth: You have to be able to take ten digit grid references from your map and input them into your gps navigation system.
Truth: You can't get ten digit GPS co-ordinates from a 1:25,000 map. Using a romer scale, you might be able to get close to an 8-digit reference with a lot of practice. The lines on the maps and your measuring device are just too thick for anything more accurate.
This however is not a problem. For walking and hiking you just don't need that level of accuracy.
All you really need to do is to estimate the six-digit grid reference of your target and that will get you within 100m.
For example: From the map, the six digit grid reference for the summit of Scafell Pike is NY 215 072. When input into a GPS Device as a ten digit co-ordinate this can read something like NY 21500 07200.
The 00's aren't that important - as this will get you to within 100 metres of your target and except at the extreme ranges of inaccuracy, and in very thick weather, you should be able to see your target - which on Scafell Pike is a huge cairn and about 100 other people sat on it munching sandwiches and looking very pleased with themselves.
NB If you were wondering, the actual ten digit GPS co-ordinate for Scafell Pike is NY 21538 07204 - which is only 38m from the six digit grid reference given above.
To see a list of walks which already have Downloable GPS Waypoint files - click here
Myth: If you make a mistake inputting data, the GPS Device is useless.
Truth: You do have to be very careful entering grid references - a wrong letter - e.g. an S instead of a Z will give some very bizarre results.
You have to be very careful about this if your intended route passes between grid references starting or ending with 99 or 01, since this is where these grid reference lettering changes. Watch out for unexpected results - especially if the direction and distance to your next target is given as something like 101 km, instead of 1km.
Inputting an accurate grid reference for a target on a wet and windy hilltop, with friends shivering and complaining, can be difficult and getting it wrong is easy to do - e.g. getting the numbers transposed, getting the grid reference Eastings and Northings wrong and so on - so practice, practice, practice.
Learn how to do it and which buttons to press (and in which order) when you are warm and comfortable until it becomes second nature.
Inputting data on the hill is best achieved by taking a reading of your current location - and then editing that reading for your next target - usually a matter of changing only 4 or 5 separate digits.
Don't rely on uploading GPS data into your GPS navigation system at home - either by hand or from your PC. If the weather changes, or one of your party has an accident you may need to change your plans and input new data on the hill - so practice, practice, practice.
To see a list of walks which already have Downloable GPS Waypoint files - click here/p>
Myth: A GPS Device won't give an accurate direction to a target unless you're actually moving.
Truth: You do need to watch for sudden changes in the direction indicator as you start to move again. This can take a little time and, potentially, could lead you into problems - above crags for example. In these situations you should use a compass to re-start your route after a break.
Myth: A Walking and Hiking GPS navigation system has to be set it up properly, otherwise it won't be very accurate.
Truth: In the UK use the 'ord srvy GB' datum and set it to read Grid North. The readings obtained will then match your OS map.
Myth: Signals from satellites can be reflected off nearby crags, or blocked off by high hills.
Truth: Though inaccuracies from the former are likely to be insignificant, you might have to wait till the satellites move a bit for the latter. It doesn't happen very often, and usually only in deep valleys. Use your compass./p>
Myth: This article has been written by a map and compass loving GPS-a-phobe.
Truth: I always carry a GPS navigation system with me into the hills and use it regularly to confirm my position. On a couple of occasions I have had to input local co-ordinates from a go4awalk.com pdf in very thick weather in order to locate a summit. On each occasion I have found this a quick and easy task and the GPS Device led me straight to my intended target without incident.
There is no denying that a GPS Device might just save your life. Finding your current location is virtually instantaneous and a ten digit GPS co-ordinate given to the rescue services via a mobile phone would speed up search and rescue significantly.
Navigation by map and compass is fun, easy to accomplish and can be very satisfying - but in really tricky situations when I need that extra reassurance that I am where I think I am, I switch on the GPS and can be found peering at the screen.
*NB. Compass and map navigation is a basic skill that you must have if you're going into the high hills, fells and mountains. If you don't have the skill - learn it. A Walking and Hiking GPS Device is not and never will be a sufficient substitute for basic skills. Click here for more information and some detailed tutorials on Grid References and Navigation Techniques