Vol 19 December 2013

GPS – A Great Tool, But Use With Care by Robert Muirhead

Dedicated Global Positioning System (GPS) navigation units and smartphone navigation apps are becoming more popular for walkers; but they don’t do away with the need to have sound navigational skills when walking in potentially challenging environments that can occur even on straightforward routes such as much of the Via Francigena.

Here I will focus on my experience with a Garmin Dakota 20 GPS unit and offer a few cautionary remarks. The following web link gives a review of the Dakota 20, but it also shows screen shots of the various functions available: http://www.gpsinformation.org/penrod/dakota/dakota.html

I have subsequently upgraded to the Garmin Oregon 650 model because it has a bigger screen.

Later I will touch on the question of dedicated GPS units versus smart phone navigation apps.

A GPS unit gives you a location in three dimensions (latitude, longitude and altitude). It is also an accurate compass. Once the user's position has been determined, a GPS unit can calculate other information, such as speed, compass bearing, the actual track walked, the distance to the day’s destination the total trip distance accumulated over a number of days.

GPS units are accurate to about +/- 15m according to Garmin, although you will see online claims for far greater accuracy.


The best GPS routes for the whole Via Francigena are available to buyers of the three-volume “Lightfoot Guide to the Via Francigena” by Paul Chinn and Babette Gallard, which I use. A quick Google search shows that other digital routes for popular stages in Italy, for example, are increasingly available online as GPX files. France and Switzerland are less well represented.

Walkers can manually create their own routes. A typical day’s stage on the Via Francigena (say 25km) can have 40 - 80 way points of the form: “North 47 degrees 14.260 minutes, East 6 degrees 01.457 minutes;” depending on the complexity of the route. So creating even one route manually for a stage can be quite tedious and error-prone, let alone the 74 stages required to get from Canterbury to Rome.

A way point is simply a location defined by latitude and longitude coordinates. But you don’t necessarily have to key in actual coordinates to construct a route. You can simply select points on a digital map using appropriate software, such as Garmin “BaseCamp”. The software will allow you to upload the route to your GPS unit as a GPX file.

Digital Maps

The Garmin Europe City Navigator map that I used is quite detailed but has to be bought separately to the GPS unit, which comes with only a very basic world map. The Europe City Navigator map has no topographical detail, but does show minor rural roads, some accommodation and other information of more use to drivers and cyclists than walkers. Garmin also sell topographical maps that show contours and are very good in terms of detail, but they are very expensive and are not justified because almost all the Via Francigena route is on well-marked roads and paths. You are not walking in a wild wilderness.

Many other digital map suppliers can be found by a simple Google search. Some cheap Garmin maps can be bought on eBay, but be careful of fakes.

While maps for dedicated GPS units are expensive, their layout, detail and text are optimised for good visibility in the field. But one big advantage of phone navigation apps is that you can choose from a wide range of inexpensive maps, some of which are free, like Open Street Maps. My Garmin map comes on a memory card and does not require an internet connection. You can download and install Open Street Maps onto a Garmin unit, but the process is tricky and you have to be careful not to wipe out other essential files - which I have done. Google to find the actual instructions and precautions to be observed.

Some phone apps allow maps to be downloaded for offline use without an internet connection. But the file sizes of maps downloaded for offline use on a long walk of a month can be many gigabytes, so you may need to be able to delete old maps and download new ones on the road. The phone needs to have sufficient memory space and you need to have a decent broadband allowance or a free WiFi link for the large downloads.

Some of the maps I have seen in phone apps are excessively detailed and also have miniscule fonts that are totally unreadable outdoors. Some have little software 'magnifiers' that you can centre over text and other detail so you can actually read it. Try doing that outdoors in wet or sunny weather!

It is also important to check that a downloaded map retains full functionality to overlay routes and your tracks when offline so that you can actually navigate with it.

These maps look impressive when sitting on your couch at home, but use them in the field before going on a long walk to see how practical they really are.

Navigating a Route

On an actual walk, a GPS unit will show you the compass direction to the next way point, how far away it is and how long it will take you to walk there based on your average walking speed as measured by the GPS unit. It will also give you an estimated arrival time at your final destination that is useful for planning your day and booking accommodation.

The unit will beep just before you reach a way point. However, remember accuracy! If you create your own route from a 1:100,000 map you might be accurate to +/-1mm on the map, but that is +/-100m on the ground. Add in another +/-15m for the accuracy of the unit itself and your waypoint accuracy could be only +/- 115m. Routes using way points chosen by another GPS unit will be more accurate, but possibly only to +/-30m.

So care is always needed when navigating in forests with a lot of side tracks – or through towns with lots of turns on small streets. GPS beeps are useful reminders that you are close to a waypoint, but situational awareness and “ground truthing” with a guidebook or physical map is still necessary. I have taken wrong turns several times in villages just by following GPS beeps uncritically at way points.

A GPS compass points to the next waypoint in a straight line, regardless of how the path to it actually twists and turns. At the start of a long, winding leg of say 1000m the compass may show the direction to the way point to be completely different to the direction you are actually walking at any given moment. If the path takes a complete U-turn on switchbacks in steep terrain for example, the GPS unit may show you to be walking 180 degrees opposite to the next waypoint. That is disconcerting until you realise what is happening. Of course, it is obvious on short switchbacks, but may not be so obvious on winding forest paths.

Situational awareness is always important when navigating, but especially so with a GPS unit. On one occasion when I was an infatuated new user of my GPS unit I came to a fork on the Via Francigena where the GPS compass indicated one fork and my guidebook the other. I chose to believe in the “infallibility” of the GPS unit rather than the human-produced guide and set out on an unplanned forest ramble to the next waypoint.

A GPS unit can also lead to overconfidence that may have unwanted consequences. I had problems after Bouvernier when I walked the Via Francigena. In one place the path seemed to continue into the forest beyond a large land slip but it soon dwindled to faint (imaginary) traces as I made my way deeper into the forest. The danger when navigating under stress is that one often sees what one wants to see!

My GPS unit showed the next waypoint was only about 700m away and I was heading to it, albeit slowly. So I opted to press on, through increasingly difficult country with very thick vegetation pulling at my clothes and pack, and steep, crumbly slopes requiring me to haul myself up the sides of loose scree using trees. The ground was very broken underfoot with large rocks and fallen branches hidden in undergrowth. After about 45 minutes of strenuous bush bashing I eventually reached the way point.

Needless to say it was a poor decision for a solo walker like me to press on. I should have gone back and looked for the correct path instead of following the GPS compass into the unknown. An accident was a possibility in such conditions. Or I could have reached a place that was actually impassable and been forced to turn around.

A GPS compass may show the way but it does not show the actual walking conditions en route – a very important point to remember before one becomes too psychologically committed to pressing on, seduced by the accuracy of a GPS unit. It’s a pretty basic warning to walkers that I ignored.

Recording a Track

A GPS unit will also record an accurate track of where you actually walk when following a route. “Tracks” in GPS jargon are where you actually walked and may contain over 1000 points for a daily stage, while “Routes” are where you planned to walk and may include 50 way points for a stage.

Tracks can be uploaded to websites and blogs and have geo-tagged photos attached, adding interest to an account of a walk. There are many excellent online blogs with tracks that can help others to plan their own walks.

A Track is useful if you go astray because the GPS unit will allow you to back-track accurately to a known point. Tracks can also be converted to navigable Routes in BaseCamp.

Experienced walkers know that things often look very different when you come to re-trace your way in forests with multiple paths and forks, especially if the light or weather has changed. It is a good practice when walking in the bush to turn around occasionally to get an idea of what the path looks like if you have to retrace it. A GPS track can be a big confidence booster when retracing one’s steps after going astray.

GPS Unit Screens

The small screen of a GPS unit is not such a disadvantage as it may seem. You can easily zoom out to get the bigger picture when required and zoom right in for accurate navigation in tricky situations and through towns.

While on the subject of screens, those on dedicated GPS units such as the Garmin series are easily readable in very bright light, whereas (in my experience) LCD screens on smart phones are almost unusable in bright outdoor conditions. I would not rely on a smartphone navigation app without first trying it out in bright outdoor conditions. Also, buy an anti-glare screen protector to reduce reflections.

Navigating with the Compass

The compass function is very useful for walkers who don’t want to slavishly follow a pre-determined route but who do want to check their navigation from time to time. Twisting tracks in featureless forests can be disorienting in dull conditions when shadows may not be visible for orientation.

I have met a few pilgrims on the Via Francigena who don’t even like following guidebook notes and prefer map and compass. That’s quite feasible in Italy; but in France, where way marking often seemed untrustworthy to me, a GPS unit is preferable to carrying the bulky 7 or 8 IGN Top 100 series of paper maps covering the route.

In general, I would prefer not to navigate with a GPS unit at all on well-signed routes such as the Camino Frances and parts of the Via Francigena in Italy because navigating by beeps does isolate you from the bigger picture and causes one to focus too much on following instructions rather than on the countryside and all it has to offer the reflective walker. But the same criticism can be made of following detailed guidebook instructions.

Dedicated GPS Units Versus Phone Apps

While my Garmin unit never fails to pick up reliable satellite signals, my phone sometimes won't detect satellites for many minutes. For whatever reason, phone GPS receivers do not seem to be as good as those on dedicated GPS receivers. Also, smart phones use data from phone towers to fix your position when they can’t detect satellites. That works well in cities, but not so well in rural areas such as on pilgrimage walks.

Battery life is better with dedicated GPS units. Using GPS on your phone, referring to the screen a lot while navigating and taking the occasional photo will quickly empty a phone's battery, sometimes in a little as 4 or 5 hours. Some phones don't allow you to change batteries; but you can buy external charging packs and even solar powered chargers for phones and that would be worth considering for peace of mind - but it means carrying more stuff (and weight). Google or search Amazon to see the big range available.

But the big show stopper for me regarding phones is the poor readability of the screen in bright outdoor light. Dedicated GPS units have far better screens.

Dedicated units are also moisture-proof. Phones may not be moisture-proof after hours of outdoor use in wet weather.

Dedicated units can be carried on a lanyard hung around the neck so you can refer to it quickly with one push of a button and let it drop to free your hands for a walking pole or whatever; but my phone has to be removed from a pocket (being careful not to drop it), woken with a button press and the screen then flicked to ‘unlock’ it. If I used a security PIN to unlock the phone it would be even worse and would be impossible wearing gloves in cold weather. It may be a small matter, but you want your navigating tools to be as simple and anxiety-free as possible.

One advantage of a phone is that you can use that one device for communicating, navigating, taking photos and storing books and music. If you take a dedicated GPS device it is one more item to carry and recharge every night.

Phone users may have very positive experiences using them to navigate in cities and in their cars. But try using it to navigate in the country and in bad weather to get a better feel for how acceptable it will be on a long walk. In particular, get a feel for battery life under realistic field conditions.

GPS units have a learning curve and some of the jargon used in my Garmin unit is pretty opaque. They are certainly not intuitive for first-time users. Phone applications tend to be (slightly) more intuitive but are often excessively cluttered with options that you have to wade through.

It should be pretty clear that my preference is for a dedicated GPS unit, despite its cost and the added cost of maps and the learning curve required. But I also have offline maps on my phone to assist with reviewing the next day’s stage and as an emergency backup if my Garmin fails.

If you may ever do only one long walk, it might be better to save money by using a phone app, especially for the well-signed, heavily-trafficked Camino to Santiago, or the Italian leg of the Via Francigena.

Even better, walk with someone who has a dedicated GPS unit for when your battery fails - or when the sun stops you seeing your screen at all.


A GPS unit or phone app is a wonderful aid to navigating confidently and for producing detailed records of your walks that can be shared online. The tools may be getting better and better and WiFi coverage is becoming almost universal, but they are no substitute for sound navigational skills and, importantly, situational awareness in the field.