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

Last updated June 2015 with information about the iPhone6 and iOS8.3

The new iPhone 6 and 6+ (pictured) have larger and better displays for map use in the field and siginicantly better battery life. Changes to Airplane Mode introduced in iOS 8.3 make it easier to manage battery life. We are easily getting 6-7 days or more of normal backcountry use without recharging.


The iPhone is arguably the best GPS/Mapping device for backpacking trips worldwide

For starters, the iPhone just plain works. We’ve taken our iPhones on numerous pack-rafting trips in Alaska, winter rafting down the Grand Canyon, technical Canyoneering in Utah, climbing in the Wind Rivers and the Sierras, long hikes in the U.S.A, Turkey, Australia, Europe, and a canoe trip down the length of the Mighty Mississippi River. In almost all ways it is superior to traditional mapping GPS units such as the Garmin. All models of iPhone 4, 5, and 6 are viable and have better functionality and display resolution than a traditional Garmin. The Six has the best display resolution and battery life of all the iPhone models, but the older models are still terrific tools.

How the iPhone works as a mapping GPS

There are several excellent iPhone apps that let you preload maps and GPS tracks into your iPhone before your trip. Then when you are out on the trail without WIFI or cell service, you can use the preloaded maps along with the iPhone’s GPS to do all the mapping and navigating you need. The downloaded maps are essentially free, and if you already own an iPhone, the cost of using it as a GPS/Mapping device for backpacking is very reasonable--essentially just the cost of the Mapping/GPS App.

The Cliff Notes Version
(basic facts for a jump start to use your iPhone as backpacking GPS)

Downloading maps into GAIA GPS for use on the trail where WiFi and celluar data are not present -- but where the iPhone's GPS still works. On the left is a partial list map sources for dowload. On the right the pink box indicates the area of the map selected for Download from a Rectilinear Area. You can also use the "Download Maps for Track" feature which automatically gets all the maps needed to follow a line, a phenomenally useful feature when setting out on a thousand mile hike or paddle. Download Maps for Track and the wide range of map types are the two features that make Gaia GPS stand head and shoulders above the other available apps..

iOS Hardware Models

For purposes of this article (GPS and mapping), the iOS devices vary in only two ways: GPS Chip and Battery Drain.

First, some iOS devices have a GPS chip and some do not.

Second, there are subtle but very important differences in battery drain between the different models and different cellular providers. See the Battery Drain and Different Models of iPhones section below for critical information.

To clarify a common misconception: You do NOT need WIFI or Cellular connection for the GPS chip to work; however you do need to have pre-downloaded the map content in order to have your current location show up on a map.

Left: the iPhone 6 in a light but protective case sitting on top of a Pint Ziploc Freezer Bag used to protect the phone from dust, scratches and water. Right: a substantial 6400 mAh external charging battery and a short lightening connector.

How to Choose your Mapping Apps

International mapping 1: Gaia GPS displaying OpenCycleMap of a section of the Lycian Way in Turkey. Red lines and blue pins show our intended route (2 alternatives shown). The brown dashed lines show trails that have been added by users to the OpenStreetMap database, wiki-style. OpenCycleMap and Satellite imagery are especially important when hiking in Turkey because the government does not publish any topographic maps. Using an iPhone with a $20 app (in this case Gaia GPS) we carried maps, satellite imagery, and track data for ~600 miles of trails in Turkey!

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).

Many of the mapping apps are not designed for hikers, and many of those that are designed for hikers are seriously flawed. Here is an annotated list of the (~80) apps we reviewed, including more detailed information about each app. We did a thorough search and review of apps in 2010-2012; subsequently we have tried learn about new high quality mapping apps, but we have not attempted to retest new versions of old apps, so some of the data in our inventory is out of date. To the best of our knowledge, the apps listed below are still best in class.

Before choosing an app, you need to decide which types of maps you want to view while hiking. You may 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, LINZ, 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. Some governments license their map data to the apps at no charge (USA, Canada, New Zealand, and some UK maps), and others do not (UK's best maps, France, Australia). When you use an app that gives access to freely licensed maps (for example USGS) you usually do not need to pay any fees (beyond the initial cost of the app) to download an unlimited amount of map data. When you use an app that gives access to maps for which the app developer must pay licensing fees, then you will need to pay for the map content. Prices vary wildly, depending on the fees that must be paid to the government for use of the maps. For example: iPhiGeNie charges 15 Euros per year to access the all maps that IGN publishes (not so bad); ViewRanger charges 90 GBP for the 1:50K LandRanger series, the Explorer series is additional (wow!).
    1. For access to USGS, NRCan, and LINZ (USA, Canada and New Zealand) maps we recommend Gaia GPS. Gaia GPS provides Satellite imagery and OpenCycleMaps in addition to the National Agency maps, and has a rich set of features. Plan to spend at least an hour learning how to use it, as some of the important features are not obvious. (Some day I will write a concise introduction to Gaia for backpackers, as many of the features are geared to day-hikers and should be ignored for backpacking.) For a user who wants the most complete set of functionality and the best selection of map sources, this is the best available app for the US, Canada and New Zealand.

    2. For access to National Mapping Agency maps of Europe, we are not experts, but propose the following.

      iPhiGéNie is possibly the best alternative for France, Spain, Catalonia, Italy, Germany and Norway (based on evaluation at our desks, we have not tried it in the field).

      ViewRanger is a solid full-featured app that offers the gold standard Explorer and LandRanger OS maps of the UK as well as National Agency maps for most European countries. We used ViewRanger for a long hike in Scotland and it was solid and met our needs. This app offers USGS maps as well as maps of Europe, however the usability and feature set are not as good as Gaia GPS and therefore we do not use it the US.

      UK Map offers freely licensed OS maps, which are not as detailed as the Explorer and LandRanger series, but will suffice for many users (especially price-sensitive users). It is elegant and easy to use, but does not support waypoints or tracks.

    International mapping 2: A section of the GR20 in Corsica France using the iPhiGéNie App. There is no substitute for getting access to the Official National maps; they are the highest quality.
  2. OpenCycleMap - aka, OpenStreetMap, OSM, OSM Topo, Cloudmade Topo/Cycle, OpenHikingMap. Many iPhone apps include this map source because it is freely licensed topographic map of most of the world (below 60 degrees latitude). Although the topographic and geographic detail is not as good as maps from the national mapping agencies, there are three important characteristics: it is freely licensed; cultural information is often more current; and it covers most of world. Take a look at the OSM treatment at their website. We have successfully used OpenCycleMaps together with Satellite imagery (with no National Agency Maps) for long hikes in Turkey, Australia, and Spain. In Turkey there were no National Agency maps available; in Australia and Spain they were available but at too high a cost for our purposes. Gaia GPS is our favorite app for this map type. There are many other apps that provide access to OpenCycleMaps, but only Gaia (that we have found) also includes downloadable world-wide Satellite Imagery, is easy to use, supports waypoints and tracks, and allows import and export of gpx and/or kml files.

  3. Satellite images - Often very useful, especially for off-trail hiking. Gaia GPS is our favorite app for satellite imagery as it offers downloadable satellite imagery of the whole world (3 different sources: Mapquest, ESRI, Google).

  4. 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 them using any iPhone pdf viewer. However, Maplets makes it very easy to find them, and by using Maplets you are able to see your current location on the map (for those maps that were drawn to scale). Maplets includes limited ability to import, create, and export tracks and waypoints, so you will probably end up using it in conjunction with a more fully featured app like Gaia GPS. In addition to park maps, Maplets has a rich inventory of maps of transit systems, bike routes, airports, museums, university campuses, etc. (Of all the apps I've used, Maplets is the one I most wish I had imagined and then produced; it is an elegant, simple, useful, concept that is very well executed.)

P.S. Here is an annotated list of some of the non-mapping apps that were suggested by folks on the forums.

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.
  3. Protect Your Phone - In terms of waterproofness and durability, the iPhone needs to be treated as you would treat a non-waterproof camera, unlike a Garmin which is designed for outdoor conditions. It can be "waterproofed" with a 5 gram $0.15 Pint Heavy Duty Freezer Ziplock, a more expensive Aloksak 4.5x7" ziplock, or an expensive LifeProof case. Even when it not raining, we keep the iPhone in a pint zip lock to protect it from sweat and dirt. LifeProof makes low-profile light-weight completely waterproof cases, which we use in very wet environments.
  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.
  6. GPS Accuracy - When using an iPhone in shallow grade mountains or flat landscapes, with minor tree cover, the accuracy has consistently been within 15 meters. When using it in deep steep walled canyons, the fix is not as accurate as Garmin, 50 to 100 or more meters off in a deep canyon (Paria Canyon in Utah). Using a Garmin and an iPhone 4 we concurrently recorded tracks on 12 miles of trail in fairly dense conifers on the west slope of California's Sierra Nevada range and could not tell any difference in accuracy. We leave it to the reader make their own determination if this level of accuracy is sufficient.

Battery Drain and Different Models of iPhones

When all battery conservation measures are in place (as per the Battery Conservation Settings section), the baseline battery drain of most iPhone models is 1-3% per day. Without proper battery conservations measures, the daily baseline drain will be at least 10% and often over 30%. By baseline drain, we mean that the phone is powered on, but asleep; it is ready for use, but the user is not actually doing anything with it. This is the background drain you will incur even if you don't take any pictures, look at any maps, or use any apps at all.

In some configurations the amount of battery drain depends on whether you are in-range or out-of-range of the cellular provider. Therefore if you test your baseline battery drain at home you are likely to get one result (in-signal-range), while when you use the iPhone in the backcountry you may get a different result (out-of-signal-range). In order to do my battery drain testing, I constructed a Faraday Cage by putting the iPhone inside a closed cookie tin and putting the tin into a microwave oven; neither the cookie tin nor the microwave alone blocked signal. We highly recommend that you run overnight tests at home with your own phone in two test scenarios: in signal range, and in a Faraday Cage.

The most important factor in preventing drain is to disable the cellular activity. The phone will incur ~10% daily drain just maintaining a signal, or 20-30% daily drain searching for a non-existant signal. Starting in iOS 8.3, you can set Airplane Mode = ON, which will disable cellular activity while leaving GPS enabled. This solves many battery management problems that previously existed. All users with an iPhone5 or iPhone6 should ensure they have iOS 8.3 (or later), and keep Airplane Mode = ON for entire duration of backpacking trips.

Based on 64 overnight tests using 18 different phones, we (authors with help from many other people) offer the following guidance about baseline battery drain, assuming iOS8.3 and Airplane Mode = ON.

  1. iPhone 6 and 6-plus: We tested nine different 6/6+ phones of a variety of models and carriers. All except one phone (noted below) had 10-12 hour drain of 0 or 1%, implying a daily drain <=3%. You can find your model in Settings->General->About->Model, and use the information in this excellent TechWalls article to understand the differences between models and to figure out which model you own.

  2. iPhone 6 model A1586: baseline daily drain is 3-8%. This phone had higher drain than any of the other iPhone-sixes that were tested. Laurie ran 29 different overnight tests on her phone, using a wide variety of configurations (in signal range or not, with ATT or Verizon or no SIM, on the counter or in motion in a pocket), and the ten-hour drain was usually 2-3%, ranging from 1 and 4%, with no discernable pattern. It remains a mystery why this unlocked model in all its configurations had more battery drain than the other models of sixes that were tested. Perhaps it is something in this particular model, or perhaps it is this one particular phone.

  3. ATT or Verizon iPhone 5 or 5S or 5C: baseline daily drain is 2-6%.

  4. ATT iPhones 4 and 4S. Prior to iOS 8.3, Airplane Mode toggled both the Cellular Service AND the GPS chip ON or OFF. iOS 8.3 is not available for the iPhone 4, and so these users must leave Airplane Mode = OFF in order to use the GPS. Sadly, when Airplane Mode is OFF, the iPhone, in some configurations, drains the battery trying to establish a Cellular connection.
    Baseline daily drain:
    1-2% per day: SIM Inactive (either locked or removed) (signal either present or absent).
    9-10% per day: SIM Active (signal present).
    30% per day: SIM Active (no signal).

  5. To maximize battery life of an ATT iPhone 4, deactivate the phone’s SIM by using one of two methods:
    1. 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. This is an elegant easy-to-use solution that gives a great result.
    2. Remove the SIM card from your phone. Be careful, the SIM card is small and quite easy to lose.

  6. Special Note about using the SIM lock feature in ATT iPhones 5 and 6:
    In the ATT iPhone 5 and 6, the SIM lock feature has a substantial bug. Unlike the iPhone 4 (where it solves a problem) it is counterproductive in the newer phones, which have more drain with a locked SIM than an unlocked SIM. Fortunately the newer phones don't need this feature since they can simply set Airplane Mode = ON.
    When the SIM is locked, Airplane Mode = OFF, and there is no signal available, the phone will drain 2-10% per hour !!!!
    To maximize battery life of an ATT iPhone 5 or 6, don't lock or remove the SIM, as that will cause a disaster when you leave signal range. Update to iOS8.3 and set Airplane Mode = ON and all will be well. We have not seen this problem reported for Verizon phones, so users with Verizon phones can lock or remove the SIM if desired.

Battery life in the field: Our daily use of the iPhone includes 5-50 sessions with a mapping app (depending on how ambiguous the route is), 10-20 photos, occasional use of bird guide apps, alarm clock, checking time, reading Wiki Offline, and nightly journal entries. All of our usage is discretionary excepting for the mapping apps and GPS reads. We scale our discretionary use based on how many days remain before the next recharge opportunity. With restrained use, most models of iPhones (especially the iPhone6) will last for a week or even ten days. If we only have two or three or four days to the next recharge opportunity, then we take more photos, play more bird calls, etc. Your mileage will depend entirely on your usage patterns. Prior to a multi-day trip, be sure to establish your baseline drain (iPhone asleep and no activity) to make sure that drain is minimized as described in the Battery Drain section. Experiment on day hikes so you can estimate your daily drain based on your own usage patterns.

Battery Conservation Settings for Backcountry 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. For day hikes or overnight hikes most of these suggestions are not important, but they are critical if you want to use an iPhone for a multi-day trip without resorting to a recharge solution (external battery or solar). Our research ended up focusing a great deal on battery life, and we hope these ideas help.
  1. Adjust the Settings to optimize for battery life. This is a comprehensive list of settings that will enhance your battery life, some of these have significant impact and some have marginal impact.
    1. The most important changes are in the "Control Center" (swipe up from bottom of screen):
      Airplane Mode = ON (unless you can't upgrade to iOS8.3 or later).
      WIFI = OFF.
      Bluetooth = OFF.
      AirDrop = OFF.
    2. Personal Hotspot = OFF
    3. Wallpapers & Brightness - Auto-Brightness allows the screen to adjust its brightness based on current lighting conditions. Or you can manually change it to meet your needs. A brighter screen is a significant battery drain, so to minimize drain you should make sure the screen is not brighter than necessary.
    4. Privacy->Location Services = ON
      Turn Location Services OFF for any app that you will be using while backpacking unless it is important for that app to have a GPS read. For example, if you use a Camera app and you want it to put a GPS stamp on each image, then leave Location Services on for that app. However, if you don't care about having a GPS stamp on the image, then turn Location Services off for Camera app so that it does not engage the GPS (and therefore drain battery) every time you take a photo.
    5. Privacy->Location Services->System Services (all the way at bottom of Location Services): Everything OFF, except possibly Compass Calibration ON. I couldn't find any documentation on Compass Calibration setting does, and when I tried to test the compass, including True vs Magnetic North, I couldn't figure it out. So you're on your own for that setting.
    6. General->Siri = OFF
    7. General->Accessibility->Reduce Motion = ON. Apple's Help Topic explains what this does. For more information see this article.
    8. General->Usage->Battery Percentage = ON.
    9. General->Date&Time->Set Automatically = OFF. This means that when you change time zones you will need to manually adjust the time zone.
    10. General->VPN = OFF
    11. Privacy->Advertising->Limit Ad Tracking = ON
  2. Now irrelevant: The following settings should be irrelevant when Airplane Mode = ON. They are relevant only to people who choose to keep Airplane Mode OFF for some reason but want to maximize battery conservation.
    1. Cellular->Cellular Data = OFF
    2. iTunes&App Stores->Automatic Downoads = OFF and Use Cellular Data = OFF
    3. Notification Center - turn off notifications for all apps - No sounds, no badges, no alerts, no nothing.
    4. General->About->Diagnostics and Usage = Don't Send
    5. General->Background App Refresh - You can disable each app from doing work while it's in the background (i.e. not open and visible on the screen). Turn OFF everything that you won't need to have running in the background while on your trip. For example, you won't need the Stocks app trying to updated stock prices while you sleep!
    6. Mail, Contacts, Calendars: Fetch New Data -> Push = OFF, and Fetch = Manually
  3. Shut down all extraneous apps.
    The iPhone supports a form of multi-tasking or background processing, and you are not likely to know what’s running in the background. Most apps do nothing while in the background and it is fine to leave them in this inactive state. A few apps (i.e. mapping apps that have engaged the GPS in Tracking mode) can actually do work in the background and consume power. In theory, if an app is using the gps there will be a blue banner displayed at the top of the screen; this banner appears when Google Maps is active in the background, but it does not appear when Gaia GPS is recording a track in the background. Since the blue banner is not a reliable indication, you need to ensure that any apps that might be running the gps are fully shut down. To be completely sure you don’t have anything consuming power, fully shut down all the apps you aren’t using before you start your trip.
    Here are instructions on how to shut down background apps.
    (For tech-weenies, here is an article that offers a more complete explanation.)
  4. Don’t use the Tracking or Guide Me features.
    Most of the map apps have features to record a track as you walk, or to guide you to a specified waypoint. But to do this it must constantly get a GPS read, which is a steady battery drain. Instead, make sure you’re not in Tracking mode or Guide Me 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.
  5. 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. 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, as of May 2012, MotionX and GPS Kit). Gaia GPS and Maplets do not have this problem and you do not have to pay attention to whether they are in the foreground when the phone is asleep. This is a significant issue and if you are using other apps, you should run your own test at home to see if there is battery drain when the app is left in the foreground while asleep. To test this, put the app in the background, note the battery percentage, put phone to sleep, and check battery percentage after a duration of at least three hours. Repeat the test with all other conditions being equal but with the app in the foreground. If there is additional drain with the app in the foreground, then you must be absolutely diligent about putting the app in the background every time you use it.
  6. Check to see if your apps give you control over when the GPS is engaged.
    Some apps have excellent battery management settings, most do not. For example ViewRanger and Gaia GPS have a setting that allows you to activate the GPS only on demand, whereas most apps run the GPS whenever the app is open. With ViewRanger or Gaia GPS, you can open the app and study the route without running the GPS, but still easily get your current location when you need it by tapping the Locate-Me icon.
  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. Of the nine GPS apps in which we tested Auto-Lock, four of them did not respect that setting (including Gaia GPS), and the iPhone stayed on indefinitely if the application was in the foreground. Whichever app you choose, you should 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. Optionally shut down the phone at night.
    We never fully shut down the phone while on a trip, but if your particular phone has measurable overnight drain you could consider shutting it down every night to conserve battery.

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