Here's my workflow of mapping hiking trails in OSM—empowered with Mapillary photos.

I consider myself very lucky as my hobbies and interests are well-aligned with Mapillary. I absolutely love maps and geographic data but I also enjoy cycling and hiking. We already know that many Mapillary enthusiasts (including myself) like to record their bike rides. This activity increases the amount of available street level photos in an area. I have already mapped endless kilometers with my bike, including many previously uncharted bike trails, like this one. These photos are perferct for mapping the bicycle infrastructure in OpenStreetMap. In this blog post, I am going to describe my mapping workflow related to another great activity—hiking.

Why even map those trails?

Hiking is a great way to leave busy workdays behind and to relieve stress. No wonder so many people choose to head outdoors and explore the beauty of nature. No matter if it's just a 30-minute walk on a short trail or a multi-night trip in the backcountry, hiking can get dangerous, especially when detailed maps are not available. Not so long ago, a hiker went missing at one of my favorite places and was found with the help of law enforcement officers with a helicopter equipped with infrared cameras.

The mapping hiker aka the hiking mapper

There is no single best method for photo mapping hiking trails. Every one of us is different and we quite often hit the trails for different reasons and with different equipment. What works for you might not work for others for a number of reasons. Therefore, it's great to share tips, e.g. like malenki, who shared his setup for recording his entire 10-day-long hiking trip in Albania.

Another motivation is to make memories and share your journey with others. Instead of selfies, you could show your Mom a virtual tour of your most recent adventure! For others, it can be specifically about recording those trails and putting them on the map so everyone could benefit from having detailed maps. My own motivation is pretty much the combination all of the above.

My gear

My gear consists of many toys. The most frequently used gadgets are my phone, a handheld GPS receiver, an action camera, a 360° camera, a DSLR, and a notebook. Now, there's absolutely no need to take them all at once. If you have at least one of the above (i.e. a device with a GPS that records your position and can take photos), you're good to go. For most people, a smartphone is plenty.

With that said, having multiple tools gives me the flexibility to adjust my method according to my trip. For example, I can just use my phone if I accidentally find myself in a new park I have previously not been to (yes, it has happened). Or I can take a 360° camera for a short hike without having to worry about battery. For overnighters and multi-day trips, I prefer bringing an action camera with external batteries and spare memory cards so I can save my phone's battery for emergencies.

In many cases, a chest or head mount is also useful so you won't have to hold your camera in your hand. They have their pros and cons. For example, I find it difficult to keep my head straight when hiking through steep terrain with a head mount, while my hands can get in the photo when using a chest mount. Nevertheless, there are plenty of options out there so everyone can find what suits best for their hiking.

My photo mapping gear. Remember, you only need a smartphone to get started!

What to look for while hiking?

Before heading out, I like to plan my hike—especially when the focus is on mapping. It's generally a good idea to map the roads that are visible from aerial imagery beforehand so I can have at least a rough idea of what's out there. With this information, I can define a preliminary route which I'll try to stick to, with adjustment according to real-world conditions. I'm not fond of hard rules so I have no problem going offroad if I find a new path that had not been visible from above.

If you're not yet familiar with OpenStreetMap, you can get started with this guide created by the good folks at Mapbox. This explains the principles and teaches you how to add basic features (e.g. roads) to the map.

Once I have mapped everything visible from satellite imagery, I am ready to head out and see the area for myself. I prefer recording my trip to the site with Mapillary as well, as I think it can help others find the trailhead. This is useful in areas where trailheads are not marked well and can easily be missed from a highway. Putting these roads on Mapillary will ensure that hikers after you can find the trailhead without missing a turn.

First thing, when arriving to the site, I turn my GPS receiver on to make sure I have an accurate track of my hike. To save battery, I don't usually photo-map kilometer-long stretches of the same trail. However, when technically possible, I don't take single shots either. To get smooth transitions between the photos once on Mapillary, it is highly recommended to take at least 20-30 photos in a sequence in close succession to one another. This will ensure that our algorithm finds adequate connections between photos and let you virtually walk through the same trail.

The most important aspect of hiking trails is their signs so I make sure those blazes are visible on the photos. With this information, I can later assign the right color and symbol to the trail on OSM without having to make sketch maps or notes in the field. However, a notepad or a few empty pages are still useful to have around.

Explore the trails of Jonathan Dickinson State Park, Florida. The photos were taken with different devices. Look for marked blazes on the trees and trail junctions captured in multiple directions.

As intersections, where hiking trails meet with each other (or with unmarked roads), can be tricky and are also one of the biggest risks of going off-trail, it is a good practice to record them from all directions so that you can figure out their relation later. Apart from this, any objects, such as picnic tables, benches, or information signs are good candidates to take photos of. All these have a place on the map and, therefore, are worth recording.

In general, you can rely on common sense and take photos of anything that you find interesting. As hiking is an activity that we do for our pleasure, don't take it too seriously. Just map anything that you like. For example, when - vegetation or habitat changes, - lights are pretty and you think photos would turn out amazing, or - you accidentally find an Inca archeological site (happy "accidents" happen).

Every photo and road segment you record will have a place on Mapillary. Even if you're not interested in putting the information you capture on OSM yourself, others might find your photos useful and use your recorded sequences to derive information from it.

Take a walk around the luxurious Kitching Creek Primitive Campsite equipped with multiple fire rings, picnic tables, a pitcher pump, and a toilet(!)

What happens after the hike?

When the hike is over, I head home and take care of the data. First, I upload my GPS tracks to OSM and photos to Mapillary. Photos taken with the Mapillary app can be uploaded directly. For external photos, you can use the web uploader, the upload scripts, or even JOSM. Once this is done, give us some time to process your photos.

Hiking trails can be complex; therefore, I prefer using JOSM to put them on the map. You can turn on the Mapillary plugin to view the photos inside JOSM or use the Mapillary website along with JOSM. Once photos and GPS traces are overlayed, you can finish up mapping roads and paths. These roads will act as a skeleton for the trail network.

Try to split ways at intersections so that each section will be represented with one way. This is because hiking trails are mapped as OSM relations that consist of many ways. Think of it as a route that you can walk down section by section. A great read on how to create hiking relations is available in the OSM Wiki. The important thing to remember is that hiking routes need to be tagged with type=route and route=hiking and network=iwn|nwn|rwn|lwn. Additional tags like operator, name and symbol are also useful.

Mapping the red trail in OSM from Mapillary photos

Apart from these, the osmc:symbol key is used to describe hiking route symbols like color, shape or text in a machine-readable format. The basic format is:

osmc:symbol=waycolor:background:foreground[:text:textcolor]

For example, yellow:white:yellow_rectangle will create an overlay on a yellow hiking trail showing a yellow rectangle in services that support this tag (see the last picture). Make sure to add this information so your trails will appear in hiking-specific OSM services.

OK, but what happens when I have done all this?

Well, then you're all set. The map data you just created is in OSM, available to everyone. The basic information you mapped, like roads, paths and picnic tables, are visible by default in most maps based on OSM. There are also specific hiking-related services that show the trail network. My favorites are Waymarked Trails for the web and OsmAnd for mobile. With OsmAnd, I can use any maps offline when data connection is not available. This is a huge advantage when hiking. Furthermore, with a little bit of playing, you can even take OSM with you on your Garmin GPS (see e.g. here).

All in all, you have just made available a lot of useful data and helped other people not get lost in the wilderness. All you need to do is find your favorite applications to take your hiking maps with you.

Jonathan Dickinson State Park, Forida, on Waymarked trails (left) and in OsmAnd (right)

Summary

As is evident from above, anyone can put their favorite hiking trails on the map with a little effort. The important thing is to have fun. Even if you don't take your survey too seriously, you can generate useful data of the trails. Apart from the trail symbols, Mapillary makes it very easy to map road surface, condition and other relevant information as well. I truly belive that mapping hiking trails can contribute to hiker safety by improving navigation. Furthermore, mapping a new area is always a good excuse to get on the trail and explore.

As I mentioned earlier, there is no one best method for mapping hiking trails. Leave a comment with your setup or continue the conversation on our forum. Take your camera with you on your next adventures and help thousands of mappers build a worldwide representation of hiking trails.

Happy mapping!

/Levente & the Mapillary team