Back to Adventure Alan’s Ultralight Backpacking Home Page: This contains a wealth of information on backpacking with gear lists, trip reports, backpacking techniques for various weather and environments (cold rainy weather, alipine hiking, desert hiking), etc. While focused on lightweight backpacking, much of the content applies to all styles of backpacking.

How to use the iPhone 4 as a GPS mapping device for backpacking

The ATT iPhone 4 (and other SIM based iPhones) is a viable tool to use as a GPS and mapping device for backpacking trips worldwide. In many ways it is superior to traditional mapping GPS units like the Garmin Oregon. This post will tell you how to get the most of your iPhone as a backpacking GPS, and we are working on a more detailed document that covers the topic.

For gps and mapping purposes, the Verizon version of the iPhone 4 is identical to the ATT version except it does not have the same ability to disable the phone, and therefore managing battery life is problematic. See the Battery Conservation section for more information.

The method for using the iPhone for backpacking is to use apps that let you preload the appropriate maps and data files over WiFi. When you are out on the trail without cell service, you can use the preloaded maps along with the iPhone’s GPS.

If you already own an iPhone, then the cost of using it as a GPS/Mapping device for backpacking is very reasonable. If you don’t already own an iPhone 4, read the full document (coming soon) for price comparison with Garmin.

Apps

There are hundreds of iPhone mapping/GPS applications to choose from, and there are seemingly new ones everyday. You should probably buy a couple applications; they are not expensive, and the map content is usually free (unlike Garmin, where you pay substantially for map content).

Here is an annotated list of the all of the apps we reviewed, including more detailed information about each app, and a list of great apps that are not described in this article. We are maintaining the list and appreciate leads on apps we misssed and corrections to inaccurate data; please post comments and suggestions below.

After reviewing over 80 apps, we’ve concluded that these are the best:

1. The basic set of apps you should own:
   1. GPS Kit or Gaia GPS. These are our preferred general purpose applications that let you store maps and gpx/kml files for offline use, save waypoints, record tracks, view trip statistics, email waypoints and tracks, etc. These are the mapping/GPS apps we recommend as the primary tool, to be supplemented by other special purpose tools noted below. (MotionX is an alternative to Gaia or GPS Kit that some people might like more, based on nuanced differences in features set.)
   2. Maplets This fantastic app complements the apps listed above. It provides easy access to a wide variety of published maps, such as state/national/county park maps, transit maps, bike route maps, airport maps, campus maps, etc. You would not use this instead of the apps that provide topo maps, but you’ll want it so you can get the agency produced park maps that often include the most accurate and current trail information.
2. Special purpose apps to use in addition to the above:
   1. If you are in the U.S. or Canada get Topo Maps. If you are in the UK, get its sister app UK Map. These are both user-friendly, fantastic little apps, with simple map downloads and lots of navigational features. They do not use OSM maps (USGS for US, NRCan for Canada, OS for UK). Handles waypoints but cannot record tracks.
   2. If you are in France, get iPhiGeNie
   3. If you need U.S. marine charts, get Marine Charts by EarthNC which provides all NOAA Marine Charts, tide information, etc. (this app is built on the same software Gaia is)
   4. If you are visiting one of the 15 US National Parks included in this app, get National Park Maps HD (from National Geographic)

How to Choose your Apps

First, you need to decide which types of maps you want to view while hiking. You are likely to want to use more than one app if you care about more than one map type. After deciding which map type you want you can then evaluate the features and usability of the apps that provide that map type. Here are the general classes of maps:

1. National Mapping Agency maps - Topographic maps issued by the government that provide coverage for an entire country (USGS, NRCan, OS, IGN, etc). These maps are almost always the most accurate and detailed source of topographic and geographic information, although they often do not have the most current cultural changes, such as new trails. For US&Canada, we like Topo Maps and Gaia. For France we like iPhiGeNie. For the UK we like UK Map. We have not evaluated apps that provide National Mapping Agency maps of other countries (except ViewRanger, whose battery draining bugs are so egregious that we don't consider it viable for backpacking); suggestions welcome!
2. OpenCycleMap - aka, OpenStreetMap, OSM, OSM Topo, Cloudmade Topo/Cycle. Many iPhone apps include this map source because it is freely licensed topographic map of the whole world. Although the topographic detail is not as good as maps from the national mapping agencies, there are two important characteristics: cultural information is often more current; and it covers the whole world. GPS Kit and Gaia are our favorite apps for this map type. Take a look at the OSM treatment at their website.
3. Regional and local maps - Nearly every park publishes a map, showing park boundaries, trails, roads, campgrounds, and points of interest. These will nearly always have the most current trail information. Maplets is a great app for viewing these maps; if the park you want is not already available, submit a request and they will attempt to add it. You could find these maps on your own, and view these maps using any iPhone pdf viewer, but by using Maplets you are able to see your current location on the map (assuming the map was drawn to scale).
4. Satellite images - Often useful, especially for off-trail hiking.

Tips on Using the iPhone

Regardless of which app you choose, there are a few considerations for using an iPhone in the backcountry.

1. Data - When you have a WIFI connection, download the map content (and trail data if you have it) that you’ll need while hiking. Your iPhone can get GPS signal in the woods, but you will be unlikely to reach the Internet for data.
2. Battery Life - Manage your battery life. Day hikers can get away without taking special steps to tend the battery life, but for multi-day trips, you must tend to these things. This article closes with detailed instructions on how to maximize battery life, because we think that’s the true crux of the issue.
3. Protect Your Phone - If you are going to be hiking with an iPhone, you should probably have ways to protect it from the elements. There are a number of cases to help protect from bumps and scratches, and a zip lock bag (Heavy Duty Freezer Pint size) or Aloksak (4.5x7") is a simple and cheap way to make sure rain or a wild river encounter doesn’t cost you several hundred dollars.
4. OpenStreetMap - Spend an hour learning about OpenStreetMap (aka OSM). OSM is a free map of the world, and many iPhone apps are based on map content from OSM. OpenCycleMap (aka Cloudmade Topo) is a variation that includes contour lines and hiking trails. Data is added to OpenStreetMap by users like us, wiki style. If your favorite trails are not there, then you can add them and the world will be a better place for it.
5. Software Updates - Occasionally check for updated versions of your apps. From iTunes, in the left side bar click LIBRARY->Apps to show your list of apps. Now in the bottom right click Update Available and proceed from there. Or, on the phone, go to App Store -> Updates and proceed from there.
6. GPS Accuracy - We have not yet compared the GPS accuracy to Garmin in a variety of conditions. When using the iPhone4 in shallow grade mountains or flat landscapes, with minor tree cover, the accuracy has consistently been within 10 meters. When using it in steep walled canyons, the fix is not as accurate as Garmin, 50 to 100 or more meters off in a deep canyon. We leave it to the reader make their own determination if this level of accuracy is sufficient. We have not tested under heavy tree cover.

Battery Conservation Settings for field use of your iPhone

It's important to follow these guidelines to conserve your iPhone battery and get the maximum battery life in the field, particularly for extended trips. Our research ended up focusing a great deal on battery life, and we hope these ideas help:

1. Make sure you can see your battery level at all times.
   Do this so you can get better resolution information than is available with the battery symbol in the upper right corner. Go to Settings->General->Usage->BatteryPercentage and set it to On.
2. Tweak all the Settings as per Apple’s recommendations.
   You can find the recommendations here. However, don’t turn on Airplane Mode as they suggest, and don’t disable location services (i.e., GPS), since that is the one battery-intensive service that you really do need.
3. Shut down all extraneous apps.
   iPhone 4 supports a form of multi-tasking or background processing, and you are not likely to know what’s running in the background. Some apps (but not most) can actually do work in the background and consume power. To be completely sure you don’t have anything consuming power, fully shut down all the apps you aren’t using.
   
   It’s not intuitively obvious how to do this. Double-click the home button to display the recently accessed applications. Touch and hold any of the icons in the bottom bar until the icon shakes and the red circle is visible. Tap the red circle to shut down an app. This looks similar to the graphic used for deleting an app, however with this method you are merely shutting it down, not deleting it.
   iPhone and Garmin Oregon 550t. The iPhone's display is larger with over six times the resolution of the Garmin. Again the map available on the iPhone has better detail than the Garmin (pictured is a section of Alaska). In this picture the iPhone is in a one-ounce hard case with rubber shock absorbing liner. The case has raised edges of to protect the iPhone display from damage. The Garmin has a similar raised edge built into its housing.
4. Disable the phone while backpacking.
   When the phone is enabled there is significant background battery drain. Baseline battery drain for ATT iPhone 4, with the phone asleep and all other battery conservation measures in place:
   <0.1% per hour (1-2% per day): SIM Inactive.
   ~0.4% per hour (9-10% per day): SIM Active (signal present).
   ~1.2% per hour (nearly 30% per day!): SIM Active (no signal).
   
   ATT iPhone 4 (and other SIM based iPhones). To absolutely maximize battery life, deactivate the phone’s SIM by using one of two methods:
   Remove the SIM card from your phone. Be careful, the SIM card is small and quite easy to lose. This method should work for any iPhone with a SIM card, not just ATT phones in the U.S.
   Or, use the SIM PIN feature (read Apple's Help Topic. and call 611 from your phone to get your initial PIN from ATT). When using this feature, you are asked for the PIN code only after the phone is fully powered down, not after each time the phone has been asleep.
   
   Verizon iPhone 4. The Verizon phone uses CDMA instead of SIM card. The only way to disable the phone is to turn Airplane Mode on. But this also disables the GPS. To make Verizon phone battery life viable for backpacking, you would need to keep the phone in airplane mode and temporarily toggle airplane mode off every time you want to get a gps read. The hassle factor would depend on how often you need a read. Alternatively, for short trips you could carry a recharging solution.
   
   Alternatively (ATT or Verizon), to retain your ability to make and receive calls and text messages with the least battery drain. Go to Settings->General->Network->CellularData and set Cellular Data to Off to ensure that you’re not unintentionally using the data network, because network access is very battery intensive. Also make sure you turn off 3G, WiFi, and Push notifications. Note: This is not as battery conserving as deactivating or removing the SIM, but this method is the least draining way to maintain basic phone and text services.
   
5. Don’t use the Tracking feature.
   Most of the map apps allow you to save the track of where you’ve been, but to do this it must constantly get a GPS read and store that data, which is a steady battery drain. Instead, make sure you’re not in Tracking mode and just get your current location when necessary. In our battery tests we found that Tracking mode consumes ~5% of the battery capacity per hour. If you do all the other battery-conservation steps, then you can use Tracking for a long day hike (~60% of the battery will be used in 12 hours of Tracking), but the Tracking feature is only viable for a multi-day backpacking trip if you have a battery recharge solution.
6. Be EXTRA cautious about leaving the GPS app in the foreground during sleep.
   If Tracking is off and the app is in the background when the iPhone is put to sleep, none of the apps we tested incurred battery drain (except ViewRanger, which was horrible in this respect). However, if Tracking is off and the app is in the foreground when the iPhone is put to sleep, quite a few of the apps we tested incurred a battery drain of between 2 and 7% per hour (including MotionX, Trail Maps by National Geographic, ViewRanger, and EveryTrail Pro; Gaia fixed this in V5.2). This is a significant issue and hopefully is a bug that the app’s respective developers will fix soon. Whichever app you choose to use, make sure you check to see if you must manually put the app in the background before putting the device to sleep, and if so, you must be absolutely diligent about doing so.
7. Beware of Auto-Lock.
   Under iPhone->Settings->General you’ll find Auto-Lock. After the user-specified duration of inactivity, the iPhone automatically goes to sleep as a battery conservation measure (since the display itself is a big battery drain). Of the nine GPS apps we tested, four of them did not respect that setting, and the iPhone stayed on indefinitely if the application was in the foreground. Whichever app you choose, make sure you test to see if it prevents Auto-Lock from engaging and adjust your behavior accordingly.
8. Keep the iPhone warm.
   Batteries achieve optimum service life if used at 20°C (68°F) or slightly below. Avoid letting the iPhone overheat in direct sun, and keep it in pocket close to your body in cold conditions. More detailed battery information in this great article.
9. What to expect in the field.
   On a six week hike in Turkey Amy and Jim used the iPhone 15-30 times per day for 30 seconds to perhaps 4 minutes per use. Our battery drain was between 7% and 20% per day. The SIM was disabled, and we used all of the battery conservation measures listed above. We recharged in shops, and we were never more than 4 days between shops. We only used WIFI (a power hog) in towns where we had access to power. On a six day mostly off-trail backpacking trip in Yosemite Alan and Alison used the iPhone, and averaged 12% daily battery drain. Your mileage will depend entirely on your usage patterns, but these two examples from different users in different circumstances give a sense for what you might expect. Prior to a multi-day trip, be sure to test your baseline drain (iPhone asleep and no activity) to make sure that drain is down in the 1-2% per day range. And experiment on day hikes so you can estimate your daily drain based on your own usage patterns.