Tuesday, 27 December 2011

Do the letters G, P, and S make you too confident? A simple how-to of GPS

These days the acronym GPS has become synonymous with the simplification of navigation, sadly it has also been the cause of a number of incidents where people have wrongly assumed that carrying a phone that has a GPS built in will miraculously come to their aid should problems arise. People start to believe that because they have a GPS they are suddenly immune to the problems associated with bad weather, poor conditions etc

For me this whole issue was illustrated on a recent trip to Snowdon. "On our approach to the summit the weather had taken a turn for the worse, cloud had come in, wind speed had increased dramatically, and on top of that it had started to rain. While descending the ranger path with the group I met a couple coming up towards us. This couple were both dressed in ¾ length jeans, t shirt and jumper, wearing trainers with trainer liners. Not knowing what else to say I asked one of them “you guys ok there?”. I was met with the following reply “yeah we’re find, do you know where the train station is? We were just going to take the train down”. When I explained they were nowhere near the train station and that the weather further up was worse than where we were, the guy I was talking to replied “it’s ok mate I got Google maps on my phone”. At this stage I said they should come with me back to the car park, a suggestion to which the freezing cold girl of the pair was most agreeable too. After giving both of them a spare jacket from my kit we descended to the car park.”

First of all let me assure you that the above story is completely 100% true, and no detail has been made up, it does however neatly illustrate my point; GPS has become a false safety net for many novices who want to get out. The purpose of this short article is to offer some simple advice to those people who are new to the GPS, and perhaps believe that their smartphone, iPhone etc will save them in an emergency. This is also the time of the year where novice walkers (or even more highly experienced) may have bought themselves a shiny new GPS unit, and, instead of learning to use it, stash it neatly on their belt for an emergency. I really do not mean this to be offensive to anyone, and by no means is the tone of this condescending, I really just want to offer simple advice to help keep people safe J

Part 1: Smartphones

The fact is that a smartphone could possibly help in an emergency on the hill, the GPS antennae’s on modern phones are often highly advanced and can offer detailed fixes. However in order to this you need to understand a few things about GPS on your phone.
Firstly the GPS is only any use to you if there is software (an app) on the phone that can use the GPS antennae to give you a fix on your position in a Latitude and Longitude format, this is the standard GPS output format and can be given over the phone to Mountain Rescue who will be able to quickly locate you based on this information. Some pieces of software will be able to use the GPS to find out where you are, and display this on a map. Whilst this may be useful in a town or city because you will be able to relate your position to other roads and buildings, in the mountains this is not the case, and programs like Google maps that do not have topographical maps will not show anything around your location.
On this basis the first thing you need to do is check that the software on your phone shows Lat/Long fixes. If it doesn’t then download an app that does, many of these are free for example; GPS essentials on Android. Once you have your app, practice using it, make sure it functions without a mobile internet connection, since many times in the mountains this type of signal will not be available. If you have software on your phone, that can display Lat/Long, without an internet connection, then you have a useful feature on your phone, provided it has battery enough to use it, and you are aware of how to do so. When you get the software on and working you are looking for a figure that looks like:53o34.544N 13o54.1346W this is the full Lat/long reference and you will need to provide the whole set of numbers in order for people to find you.

Part 2: GPS handsets

Many would be walkers buy a GPS handset but have no idea how to use it. It’s often one of those gadgets that people buy because it seems like a piece of gear they need. The fact is (cliché I know) GPS is not a substitute for good map skills. So do not go out into the mountains without a good knowledge of map and compass, and the appropriate equipment.
That said, if you do have a GPS it is a piece of gear that can really help in an emergency, and the good news is that regardless of the brand of GPS you have the approach to finding your location is very similar, and the below is a general overview of how to get that information.

Step 1: Turn the GPS on and wait for it to get a fix. This will be quicker if the GPS has already had a fix during the day, you can find your progress towards a fix on a screen that will be called “satellites” (or something similar). This will display a bar graph of signal strengths, and will usually indicate if you have a fix by saying “4 metre fix” or something similar.

Step 2: Once you have a fix, you need to find the location data. On some GPS sets for example the newest Garmin eTrex 10, this information is found on the satellites page so there is no need to scroll around trying to find it. On other models this may be found on a dashboard screen or home screen. You are looking for a figure that looks like: 53o34.544N 13o54.1346W this is the full Lat/long reference and you will need to provide the whole set of numbers in order for people to find you. You may also find the data is provided as a grid reference and will look like this: SJ 04566 78534 and you will need to provide the whole number including the letters at the start.

Above: Examples of GPS position screens, the red arrow marks the where you can find location. In the first screen it is shown as a grid reference, whilst in the other 2 it is shown as Lat/Long.

I close with a quote from Brecon Mountain Rescue team's Mark Jones, regarding a couple who were rescued by a smartphone when they were directed to download an app to the phone in order to be able to provide the team with an accurate location:

“Technology saved us all a night on the mountain, but it can never take the place of a traditional map and compass and being properly prepared.”

So there are the basics; if you want to know anything about your GPS, feel free to email me directly, I’m always happy to help.


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