Thursday, April 2, 2015

Using a Smartphone for Navigation on the Arizona Trail

Many long distance trails have navigation apps for smartphones.  But what do you do if you are hiking a trail where there are no dedicated apps (like Guthook's Guides)?  Here, I describe the navigation problems we had on the Arizona Trail and give an overview of how to use your smartphone as a GPS.
Which way do I go? Photo by Jan.
How navigating on the Arizona Trail was challenging

If you have hiked well-established long distance trails like the AT and PCT, it might be hard to imagine why navigating on the Arizona Trail could be challenging.  For being such a new trail, the Arizona Trail is remarkably well-signed and we were impressed by all the good, clear trail there was. 
Brown carsonite Arizona Trail signs were always a welcome sight.
But because the Arizona Trail is newer and not as heavily traveled, navigation was more tricky than what I’d encountered on the AT and PCT.  It is important to understand the situations where navigation is difficult so you understand why it could be helpful to use the your smartphone as a GPS device.
Faint, indistinct tread sometimes can make it hard to distinguish the Arizona Trail from cow paths.
The Arizona Trail uses a combination of trails and roads pieced together, in addition to parts that were constructed specifically for the Arizona Trail.  Therefore, the character and signage of the trail changes as it goes through different areas.  You might be on well-graded single-track tread, then pass through an area with cow paths galore heading off in all directions, then turn onto a steep ATV road, and then follow paved roads into town.  Signage and ease of navigation is constantly changing.
Paved roadwalks were often unsigned, and were where we used our smartphones often.
Because there are few hikers of the Arizona Trail, you cannot assume that the most well-traveled path is the Arizona Trail.  In places with more cows than hikers, animal trails can be bigger than the Arizona Trail and form complex networks that get confusing and are unsigned (cows apparently don’t need signs).  In other places, dayhikers use the trail systems most often so their trails are clear and well-trodden, and the Arizona Trail junctions may be hard to find.
Which trail is the Arizona Trail?
The signage doesn’t always tell you which trail or road is the Arizona Trail.  This was most frustrating in popular hiking areas like Saguaro National Park.  Local trail names were shown, but nothing showed which way the Arizona Trail went.  Other times only the way north on the Arizona Trail was indicated, southbounders needed to figure it out themselves.  The guidebook and databook do describe the way to turn at each junction, but we were going southbound so it wasn't straightforward to reverse the directions in some cases.
Arizona Trail sign pointing in only one direction.  What's a southbounder to do?
Finding off-trail water sources was also a challenge.  On the AT, signs and blue blazed trail led the way to water.  On the Arizona Trail, the majority of off-trail water is unmarked, and you’d have no indication of how to find it unless you keep your eyes peeled and follow the water report or databook’s directions  “0.3 m NW” to the tank.  But when you get to the mileage listed for the watersource, there are multiple cattle paths up the wash.  I’d pull out my compass but couldn’t figure out which NW route to take. 
The databook (from the AZTA) and water report provides a rough guide for where to get water.
All of this means that most of the time you will follow your databook, but there will also be several times throughout the day where you will stop and wonder, “which of these two trails at a junction is the Arizona Trail?” or “am I still on the Arizona Trail?” and “where the heck is the water?”

Using your smartphone as a GPS

Many experienced northbound hikers that we met were also frustrated by navigation on the Arizona Trail.  They’d gotten off trail frequently, and been confused at unmarked trail junctions.  Several of them had hiked the AT or PCT using Guthook’s Guides on their smartphones, and wished they had a navigation app on their smartphones that would work without cell service.  I was surprised so many experienced hikers didn’t know that they can use their smartphones as GPS units and store topo maps for offline use!

Smartphone can function as a GPS unit offline (i.e. even if you don’t have cell phone service) by using one of several navigation apps.  I will not review the various apps here (I use Gaia GPS and Jan used Trimble), but their use is similar.   First, download the GPS tracks and waypoints (usually a .gpx file) onto your smartphone.  We got the GPS files for the Arizona Trail by becoming members of the Arizona Trail Association.  Then you transfer the GPX file to your smartphone (I save it in my google drive folder for offline use) then open the GPS file using the navigation app.  The interface then looks very similar to a GPS unit.  Next, download the topo map files to the smartphone manually so they can be used offline.

Then on the trail, you can use the smartphone like a GPS to locate your position on your topo maps.  This is because even without cell service, your geographic location is still figured out once you take your phone off airplane mode.
Even without service, I could checked my location (yellow triangle) to find I was not on the right trail (light blue solid line and red dots), and had missed the turn and had to backtrack.
We usually only used our smartphones to navigate when we were at unsigned trail junction or when we suspected we were no longer on the trail.  Usually just a couple times a day.

Learning to use your smartphone as a GPS requires a bit of a learning curve, so we suggest you try it well before you head out for a trip.  It took me months to learn the finer points and become a skilled user (and to figure out how not to rapidly drain my battery).
The topo maps on my smartphone show exact locations of water sources relative to the trail.
Downloading topo maps

When you download the topo maps manually, you choose how much coverage you want and how far out from the trail you want to download.  You also need to select the type of topo map to download (each “layer” shows different information).  For a long trail, you will end up with a bunch of different saved maps, all with potentially multiple layers.  If you download a larger area, it requires larger file sizes.   If you end up hiking further away from the trail beyond the extent of your downloaded topo maps, you will literally be in a gray zone- you will see your position relative to the gps tracks, but you will not have the topo lines or map for where you are.  This is why it’s important to practice using navigation apps before you hit the trail so that you can learn how much map to download and which layers you find useful— there is definitely a learning curve to this.  File sizes for the maps may be large, so you may need a system for downloading them during resupply stops.

Battery use

Navigation apps are notorious for draining smartphone batteries.  This varies by app, smartphone, and usage.  There are many articles written about this topic (see below).   Again, practice before you hit the trail to learn how to reduce battery usage.  When used efficiently, I had no problems.  But this is because I know what settings to use and I also only use the app sparingly, checking location only a few times a day and never leaving it on for more than a moment.

The GPS tracks are not always right

Several times there was conflict between what the GPS and our instincts indicated was the trail. Follow your instincts over what the GPS says.  The GPS tracks and waypoints contain errors. The first time we noticed this was on passage 15 (between 15-123 and 15-125).  Cow paths and dirtroads crisscrossed this area, but we were following dirt road and rock cairns.  At an unmarked dirt road junction, both Jan and I check our location on our phones, and both of us saw we were off the GPS track.  We backtracked all the way to our last trail sign, and saw that the GPS tract couldn’t be right- it led off into the cactus and scrub.  This convinced us that the tracts were wrong, and to follow our instincts and the cairns.  Of course it would have been easier if there were actual trail markers at junctions, but for areas like this one where there were so many indistinct old roads and animal paths, that would be tough.
Following the rock cairns, not the GPS tracks.
The GPS tracts and cairns didn’t match a second time in the Wilderness of Rocks area (Passage 12).  Again, we backtracked, and saw the tracks led down a wash where the cairns clearly indicated another route.  We concluded the trail had been rerouted and the GPS tracts hadn’t been updated here either.
Here I was on the trail, but the GPS line is wrong.
Another time (near the Gila River) we noticed the waypoint indicated we’d only done a few miles, but our instincts said we’d hiked more.  We suspected a mistake in the waypoint labeling, and at the end of the day, we confirmed our instincts had been correct.

Take home message: Know your pace, be able to estimate your mileage, and trust your route-finding ability over your electronics.
The Arizona Trail follows lots of dirt roads where we'd cruise and be prone to missing turnoffs.

Using your smartphone as a GPS provides a good solution to the navigation challenges of the Arizona Trail.  If you are already used to using your smartphone as a GPS to supplement your databook and paper maps, you can still do so if you can find GPS tracks for your trail.  For the Arizona Trail, these can be downloaded from the Arizona Trail Association website (if you become a member).  You still have to use your brain, but using navigation apps can make your hike much less frustrating when the junctions are ambiguous or when you get off-trail.

Note that dedicated apps are coming out for the Arizona Trail, and that the Arizona Trail is constantly changing.  I hope that this article serves as a useful guide for those interested in planning a trip on the Arizona Trail or other long trail without a smartphone app.

Also, remember that it is always advised to use paper maps and not rely solely on electronics.  We navigated with the databook primarily, and used our smartphones for navigation only a few times every day.  For a less well-marked trail, better topo maps and a dedicated GPS unit would have been a better choice.
Helpful signs are being added all the time to the Arizona Trail as this trail develops.  We're happy this trail is improving all the time due to the efforts of trail maintainers, volunteers, and the Arizona Trail Association.
Further information

Adventure Alan’s how to use the iphone as gps mapping device (provides details and is an excellent reference for how to save battery life)

Guthook gives tips on how to get the most from your smartphone battery.

Discussion of GPS device vs. Smartphone navigation on Section Hiker

Gadget’s Guide to selecting a smartphone for long distance hiking

Support the Arizona Trail by becoming a member of the Arizona Trail Association or by volunteering!  


  1. So I just used Gaia for the first time on Lowest to Highest and it worked perfectly. I did not read the manual before leaving and wish I had. Is there a tutorial that really helped you make the most of this app?

    1. I never found any good article on how to use Gaia. I just learned by trial and error, and then emailed one of my hiking mentors when I had questions and problems with it.

      One of us should write up a tutorial!

  2. GREAT job, I'm linking to your post rather than creating another which IMO would be much less informative.

    1. Thanks, Jan! Let me know if I missed anything important, especially since you were using a different navigation app.

    2. The Trimble app on my Droid Maxx is very battery frugal. With this app I have the option of downloading maps for offline use. This saves me the time of needing to cache in advance; HOWEVER, one of the downfalls is that they are organized by county, something we don't always know when in the field.

      The most important advice IMO is practice, practice, practice, especially with phone in airplane mode and off trail. I started with a handheld GPS unit many years ago and transitioned to a phone app several years ago. Learning to use this technology takes time and experience, it's not something to wait and figure out on the trail when it's most needed and batteries are precious.

      Another thought was use of my solar panel. Although it's an inefficient charging solution, it's almost always available and for those of us choosing to be technology dependent, it offers a weighty level of insurance.