Off road navigation can be a daunting task. When we travel to paved, yet unfamiliar places, for business, vacation, or for whatever reason, we have the power of real time navigation right at our fingertips... literally! We whip out our phone, or reach up to our navigation device, and in a matter of seconds and a little engagement of our appendages, those AI voices we know and love are giving us turn-by-turn directions to our destination, which is usually a street address. However, when we leave the pavement, those services may become unavailable, due to a loss of internet connection, a lack of routable roads, or other reasons.
This article aims to shed some light on the fundamentals of GPS and geographical coordinates, the basics of off road navigation using mobile apps, and handling GPX files.
The Basics of GPS
GPS stands for Global Positioning System, a service available to pretty much anyone, anywhere in the world. There are other systems like it, but GPS is owned and maintained by the United States, and therefore used by almost all US location-capable devices and services.
When you open Google Maps, Apple Maps, Waze, or any other app on your phone that shows your location, a little chip inside your phone talks to satellites floating around in space. The chip (a GPS receiver) asks the satellites to find your location, and transmit your current geographical coordinates back to your device. Those are the basics.
If you are within cellular data coverage, you should see a map, details of what's around you, advertisements, etc... if you are NOT within data coverage, you will likely be advised by your application that you do not have an internet connection.
In the above screenshots, the first was taken with a cellular data connection. As you can see, your phone will download the maps and plot your location on top. The second was taken with the data connection disabled. In this scenario, your phone is unable to download the map to display on the screen. However, your location is actually still shown, as that data is provided by the GPS satellite system, you just have no way of visualizing your location relative to your surroundings. In this situation, your map is essentially useless.
Fundamentals of Geographical Coordinates
Out in the dirt, there are no street addresses! So how the heck do we identify, or reference, a specific location without an address? We use coordinates! Coordinates are numbers which determine the position of a point in a particular space; in our case, the earth!
There's a good chance you've seen a set of coordinates before. A common format looks like this: 37.444139, -115.732763. These specific coordinates mark a position northeast of the famous Area 51, an iconic location recognized throughout Nevada. If you enter these in the search box in Google Maps, you will find yourself looking at an aerial view of essentially nothing, near a geographical feature called "Bald Mountain". If you find it, you'll discover that its name is quite appropriate.
Fun Fact: The location represented by coordinates 0,0 is where the Equator and Prime Meridian intersect. The location is known as "Null Island".
Coordinate Formats
Formats. There are a bazillion of them. Luckily, there is one most commonly used by standard civilian GPS apps and computer systems in the United States: Decimal Degrees (DD).
A set of coordinates has two components to reference a location: Latitude and longitude. Latitude specifies the north-south position relative to the Equator, while longitude specifies the east-west position relative to the Prime Meridian. One easy way to remember this is to associate the word "latitude" with a ladder, and the rungs are the lines that represent the north-south position.
Credit: Illinois State University
Let's go back to the earlier example: 37.444139, -115.732763. These coordinates are expressed in Decimal Degrees (DD). Since the latitude is positive, the location falls north of the Equator, and since the longitude is negative, we know the location will be west of the Prime meridian. Think of the set of numbers as a whole, referencing a spot on the earth relative to 0,0. So our example set indicates that we need to go up (north) and left (west) from 0,0.
By the way, you may see a set of coordinates like the ones above, but with fewer digits after the decimal. Don't panic though! It's completely normal. This is called "precision". Essentially, the more digits, the higher the accuracy of the location point. Using our example:
37.44, -115.73 (two decimal places) would typically narrow a location down to a small town.
37.444139, -115.732763 (five decimal places) can be as precise as an individual tree.
For off road navigation and mapping, I highly recommend using a precision of five decimal places. Most apps and devices will already do this!
So how does this apply to me?
You may be thinking "Yeah, okay cool numbers Max, you sound so smart (we know you're not) but what am I going to do with this stuff?" Well, at the very least, you should now have a bit more understanding of what these numbers mean when you see them. Generally, you can paste a set of coordinates into any map service, app or GPS device. This includes Apple and Google Maps.
Also, you may need to give these coordinates to someone to help them find you! Find Me SAR is a website with one function: to display your current coordinates. If you open your phone's web browser and navigate (Ha! Pun totally intended) to findmesar.com, you will see something like what's pictured below:
Note: You might be asked to "Allow the website to use your location." (obviously allow it or this won't work!)
Although you can scroll through several different coordinate formats, the very first one that is shown is Decimal Degrees. All US 911 call centers recognize DD formatted coordinates. If you are on the phone with 911, you can say:
"My coordinates are 39.189800 by negative 119.738500" and they will understand.
Again, these are just the basics. For the cartographers out there, I know your blood pressure has already risen to an unsafe level due to the lack of detail I provided. Take a deep breath and move on.
General Use of Off Road Apps
I could write an entirely separate article on different off road navigation applications and devices. However, for the sake of simplicity, I will be using Gaia as an example for this section. If you are not familiar, Gaia is an outdoor navigation and mapping platform available as both a mobile device app and a web-based system. Gaia is among the leaders in its class and I highly recommend it for outdoor adventurers of all types and skill levels. Check out their website when you have a few (after you finish reading my nonsense, of course).
Now, I won't be getting into the specifics of Gaia's features, which are outlined in detail on their website's "Help" section. I will simply be providing general use cases for this type of app, and how it applies to the off road world.
Where the heck am I?
Have you ever turned off the highway after determining that you've had enough pavement and driven aimlessly into the endless geographical deposit of dirt, otherwise known as Nevada, and then stopped and looked around, asking yourself the question: "Where the heck am I?"
Now, assuming you have a cell signal, you can open your phone and launch Gaia (or other preferred app). If you don't have a signal, then hopefully you have some offline maps cached and ready to go. Offline map caching is a function of all major navigation apps, and you should learn how to do it for your specific app or device.
Anyway, when launching Gaia, the first screen you should see is a map with a blip in the middle. That blip is you. In many cases, your location will be represented by an arrow, or other distinguishable icon, that typically rotates according to the direction you are facing.
Take a look in the top bar towards the right. Recognize anything? That's right, they're coordinates! To where? YOU! We've all seen it on the recovery pages - someone gets stuck and in their cry for help Facebook post, they write something like this:
"Help me I'm stuck in the mountains above that one city if you take the second left and drive for 20 minutes then turn left on the dirt road then drive for another 10 minutes then turn left at the cactus you'll see me!"
Okay first of all buddy, at least tell us what kind of cactus we're dealing with here, or we might not find you! Second, how about some coordinates?? They're right there on the screen, already in DD format for you to copy/paste into your request for assistance. Members of recovery groups are often experienced, and know the local trails enough to find their way to you with nothing but your coordinates.
Don't forget that you can also use Find Me SAR to get your current location in the proper format.
Finding a Trail
You may see a topographic map, a satellite view, or some other map style. Streets and landmarks may be overlaid onto your map. In the off road world, we can use these different overlays to find our way around, and to locate other trails in the area.
All of the major land management authorities in the US provide data sources to Gaia and others, so that established trails are marked and presented to the user. You may even be able to use your app's routing feature to navigate to another location!
Not all of the roads are labeled and routable. You might see them in the satellite view, but they won't have a name, an overlay, or otherwise any other information. Now don't get too excited, Christopher Columbus, these areas aren't necessarily uncharted, so traces of other earthlings may be present.
Depending on your setup and subscription, you may have access to several other map types as well. Free versions of apps typically only provide basic map types such as street and satellite. I will admit that I heavily favor satellite imagery over topographic maps pretty much all the time. In my opinion and experience, topographic maps are somewhat of a thing of the past. Newer technology allows terrain data to be overlaid onto satellite imagery, and elevation data is so easily available with a simple click on the map. Your mileage may vary!
Working With GPX Files
Short for GPS Exchange Format, a "GPX" file is hardly more than a text file that contains a list of coordinates. When imported into an app like Gaia, the coordinates are plotted out on the map and connected together with lines. When this happens, a track is formed and displayed on the map.
For more complete info on GPX files, I recommend an article by HikingGuy. Although the article is more geared towards hiking, the file structure and concept are the same. You can view that here: https://hikingguy.com/how-to-hike/what-is-a-gpx-file. The article is a bit more on the technical side, so if you're not really too concerned about what's inside a GPX file, take a pass and keep reading my scribblings.
No doubt you've seen the term "GPX" floating around. Most trail database websites offer a way to download GPX files for specific routes, so that you can open them in your GPS device or app. There are other file formats as well, but GPX files are the most universally supported.
Our own database at Wild West Jeeps offers GPX, and as of recently, KML files. We aren't going to talk about KML in this article, but for those of you who use Google Earth, you're welcome :)
The Nevada Off-Highway Vehicles Program website also has downloadable GPX files, along with some additional formats.
Tracks, Routes & Areas
A track and a route are essentially the same, but created differently. Typically, a track is created by recording your location at varying intervals while moving. This is what you're doing when you press the "Record" button in your Gaia app. A route, however, is generally created either in an app, or on a computer, and then exported in some fashion, like a GPX file, for one to follow along with using their GPS device or app. Think of a route as a plan, and a track as what you actually did!
Track: Hunter Lake Trail - Reno
An area, on the other hand, is generated from a list of coordinates that create a perimeter outline of a space on a map. Some apps display them with an outline, and a fill layer to show the extent of the area.
Area: Prison Hill - Carson City
Waypoints
Whether you're actively recording a track or just following along with your map open, you can still drop waypoints onto your map to save notes about a specific spot. In the above screenshots, there are small icons placed along the Hunter Lake track and inside the Prison Hill area. These are waypoints, and when opened, they contain notes about that location. For example, the purple icon in Prison Hill represents the entrance from the main road.
Waypoints are great for saving potential camping spots, areas that are marked as private property, gates, spots that you'd like to come back to, or any other reason really!
Recording a Track
No matter the circumstance, the location, how well you know the area, or how capable your vehicle is, I ALWAYS advocate for recording your track. With Gaia, it's as simple as opening the app and pressing the "Record" button. You can add details later.
Recording your track accomplishes a couple things:
1. If you get lost, you can follow your track back to your starting point. You got there, right? So you can get back!
2. You now have a way to see where you've been, and also where you have NOT been!
3. You can now export your route and add it to the Wild West Jeeps trail database, which of course is far more important than your personal safety and exploration records.
Recording Settings
A couple things of note when recording tracks: nbsp;
First, you should make sure your app or device also records elevation data. Many devices (including phones) have barometric altimeters. However, in my experience, unless you have some sort of aviation equipment that you carry around in your Jeep, your consumer device's altimeter is probably not that accurate.
With that said, you should attempt to set your device to use DEM data. DEM stands for Digital Elevation Model, which is data held by the US Geological Survey that essentially allows your device to look up elevations for any given set of coordinates. DEM data comes from... actually, never mind.. not important for this article. It's science (bro).
The next thing you should attempt to ensure is that your device is recording location points at close intervals. Yes, this uses more power, but chances are you've got some sort of fancy schmancy pluggy thingy that puts the juice back into your stuff so you don't have to worry about it. Most apps and devices will do this automatically (somewhere around 1 second intervals); however, it's always good to make sure. If there is no setting for this, you can safely disregard.
The farther apart your location points are, the less complete your track will be.
After verifying these things, or if your setup does not have these options, you're off to the races!
Saving & Exporting
Once your track is complete, you can add details (name, description, notes, etc...) and store it permanently in your device, or if you're using Gaia, your track will synchronize with your account so you can view it on other devices, or on your computer.
Your track can then be exported in GPX format. I actually wrote a guide on how to export tracks to GPX format, and then upload them to our club's trail database. If interested, click here. Note that this guide applies to iPhones only. Android phones are a little different, and more info can be found in this guide.
Importing
If there's a way out, there's a way in! That means you can also import GPX files from another source into your navigation app or device.
This process is different depending on the type of device you have, and you should refer to the instructions for your setup for details on importing a downloaded GPX file.
I am going to be making some tutorial videos soon, that will show you how to import and export using both iPhone and Android phones. Watch for those in the coming weeks!
Visualizing
If you possess a GPX file and want to see how it translates to map form, there is a handy online tool called GPS Visualizer, which can take your GPX file and plot it on a map. The tool has a whole bunch of settings, but in its most basic usage, you simply choose a file and follow the instructions! To check it out, go here: https://www.gpsvisualizer.com.
Links
https://www.wildwestjeeps.com/trails
https://hikingguy.com/how-to-hike/what-is-a-gpx-file
That's it for this article! Thanks for sticking with me to the end. If you are reading this, hopefully you have a clearer understanding of some of the more common questions about GPS as it relates to off road maps and navigation.