How to Use Your Cell Phone for Backcountry Navigation
Thru-hikes, especially the more difficult off-trail thru-hikes—the Continental Divide, the Wind River High Route, the Hayduke Trail—require the savvy of an experienced hiker, but modern technology can simplify the trouble of navigating via map, tracking your coordinates, and charting a course.
Yes, there is a lot of incentive for leaving your mobile device at home while you venture into the backcountry. Most importantly, the damn thing won't work outside of cell signal, but it’s also a great feeling to unplug. Some of you may prefer a laminated map and compass; after all, the technology has been reliable for hundreds of years.
Still, cell phones do much more than place phone calls these days, and you won’t be able to send and receive texts or update social media while your phone’s GPS tracks your location. On a long thru-hike, the power to know your location instantly without having to tango with compass and paper is very useful indeed, especially in an off-trail environment, especially on long, 25-mile days when time is more valuable.
A Word of Caution
If you are new to backcountry navigation, it is absolutely essential that you learn to navigate by map and compass. While there are risks to any navigational aid, proper training and experience is irreplaceable, and knowing how to move in and out of unfamiliar terrain with the proper references can very easily save your life. Experienced hikers may choose to replace their map and compass with the system outlined below, but only do so if you know yourself to be an experienced backcountry navigator—and even then, it is smart to prepare for the worst by carrying a backup.
Tools of the Trade
CalTopo (https://caltopo.com/map.html): CalTopo is a backpacker’s best friend, providing high-quality digital maps for digital use and printing. With CalTopo, backpackers can create geospatial PDFs, digital documents that are layered with GPS coordinates that your phone will use to place your location on the map.
Avenza (https://www.avenza.com/): a freemium app, Avenza is highly worth the annual upgrade subscription of $29.99. With this app, you can locate yourself on the maps you create in CalTopo. The upgrade price allows you to download and use more maps, making the app much more practical. It also features an extensive map store with more than a million maps to download.
Create Your Maps
With CalTopo and Avenza, you have a couple options: create your maps in CalTopo and upload them to Avenza yourself, or skip the work and buy a ready-made map in the Avenza store. In many cases, you can find what you need in the store or elsewhere on the web. Simply search for it.
Otherwise, it’s relatively easy to coordinate your route planning with map creation in CalTopo. In many cases, you can search the web for a CalTopo route already plotted in the map editor. The wisest thru-hiker will take the time to plot the entire course of the trail in its entirety, and CalTopo has the tools for that. Simply plot the official trail coordinates using the mapping tools in CalTopo, or use the maps themselves to find a potentially feasible route.
CalTopo is a fickle beast, and in order to get your map imbued with the proper coordinates, you need to create your geospatial PDF in a specific way. Fortunately, it isn’t technically challenging. For the sake of brevity, we’re going to use an existing map that can be found online. We’re going to use the Hayduke Trail.
Search Google for “Hayduke Trail” and “CalTopo.” There are several options to choose from. Either of the top two are useful. These links will bring you the Hayduke Trail plotted in myriad ways: by sections, in its entirety, etc. Again, the wiser hiker will cross-reference these trail maps for accuracy.
Generate only one section and PDF at a time. While CalTopo’s free version allows you to stack up five different sections at a time (each section gets a red box), creating a six-page PDF, it unfortunately disables the website’s ability to layer geospatial coordinates into the PDFs. That means that Avenza won’t recognize coordinates on the maps once they’re uploaded into the app. If you generate more than one, you won’t be able to use your phone’s GPS capabilities to place yourself on the map, and thus the map-app combo becomes an essentially useless visual aid.
Upload Your Maps
Next, we need to upload our maps into Avenza. You have two options: upload your map into Dropbox and import via Avenza, or use CalTopo’s unique URL to upload directly. Both are fantastic options, and uploading into Dropbox gives you a cloud-based backup that you can resort to should something happen to your phone.
- Select the “Print to PDF” option from the toolbar in the header. This will open a new window.
- Select from the sidebar desired options, including scale and grid lines. Typical hiking maps use a scale of roughly 1:25,000. Most of these options are preset and appropriate, and scale is most important. Also important: you must select the Geospatial PDF format.
- Position the red box on the map to the appropriate section of the trail.
- Click “Generate PDF” at the bottom of the sidebar.
- Repeat for each section of the trail. Allow for some overlap between trail sections. This will help you off of one map and onto another in the field.
If you open the map, it should display coordinates as you pan around. If it doesn’t, you know your map hasn’t been referenced, meaning it doesn’t have GPS coordinates, and it isn’t a geospatial PDF. You missed a step. Try again!
Once on the trail, using the map is as easy as opening Avenza to the proper section! If you’ve followed these steps, Avenza will display your location in the same way that your other map apps do. Consider one of the hardest navigational challenges solved.
- Once your map is created in CalTopo (this can take a moment), download your map to your computer’s Dropbox folder. The map will automatically sync if you’re running your Dropbox helper.
- Copy the link from CalTopo. In the example above, this link is https://caltopo.com/p/292G.
- In Avenza, click “My Maps” and tap the plus sign in the top-right corner.
- Tap “From Dropbox” or enter a URL.
- If necessary, copy and paste the CalTopo URL into Avenza.
- The map will automatically download and add itself to your map library.
- Voila! Take a look at the bottom and you’ll see the map coordinates at the targeted location. Within this screen, you can pan from corner to corner.
No system is perfect. What challenges do you need to anticipate with this wayfinding method? Let us know in the comments.