Trailforks Basemap for Garmin

Mar 6, 2017
by Todd Neumarker  
I have been using the Garmin Edge device for a quite a while now. Once basemaps made their way into the Edge series back around 2009, I purchased the Edge 705. The maps back then were similar to what you might see in your car, and like all maps available at the time, they were designed mostly with automobiles in mind. Since then I have continued to upgrade my bike computer in hope that the maps would improve, not only to include mountain bike trails, but for the theme to be specific to bike riders as well.

Trailforks Basemap for Garmin

Since the release of the Trailforks Mobile App, the need for my Edge series unit has waned. However, I often still find myself throwing it onto my stem and relying upon my latest version, the Edge 810. There are some areas that it shines and continues to provide the following benefits where my phone would sometimes fall short:

1) Battery life
2) Mounting convenience – Didn’t have to bust it out of my backpack
3) Durability – That unit flew off my bar when I hit a cattle crossing and it skipped on the pavement for about 10 meters. Only scratched the corners, and didn’t even scratch the screen.
4) Map – If I was riding somewhere new, in town, on paved roads, it helped a little, sometimes.

Trailforks Basemap for Garmin
For all intents and purposes, the map provided little help out on the trails. I had just about given up on any hopes of a real bike-centric map, until I heard that the Garmin Edge 1000 was based upon OpenStreetMap. I thought that this would be the perfect opportunity for Garmin to revamp the theme from the old NT series Automobile Maps to a true bike-centric map. And while the update did improve with the advent of some actual trail data, the theme was still basically the same.

Here at Trailforks, we decided to take a crack at creating our own Garmin Basemap theme. Now keep in mind that these devices are low resolution with a reduced color palette as compared to a modern smartphone. This is mostly to accommodate rendering of large maps on a small device, all while maintaining the battery life. And dare I say, keeping costs low. Well, ahem, moving on and without further ado, we present the Trailforks Garmin Basemap.


Once again we find ourselves trying to figure out how to de-emphasize roads, and emphasize all things bicycle related. As we did with our Traiforks Custom Basemaps, all paved roads are stripped of their flowery designations, and are reduced to a grayscale line. Dirt access roads are given a hint of dirty color, but the real colors are exactly where they should be, on the trails. And no more zooming down so low that you can only see the trail and nothing else. I like to see an entire trail system glowing bright revealing all the connections and ride options.

Trailforks Basemap for Garmin
This being an initial (beta?) release, we started simple and are only including POI's that we feel make a real difference. We have always liked to keep our maps very clean by not enabling every POI, route, and layer, but provide maximum utility by allowing the user to pick and choose what they want to see. Such an approach is more difficult with a single base map, so we started by only including the bare minimum: Trails, Parking, TTF, and Bike Shops. Of course, the most important feature is the trails, but there needs to be some clarification on how we display them.


This is where we had to deviate from the “standard” green, blue, and black. Initially, my first version of the map used the IMBA Difficulty Rating System, but this proved difficult to read on a Garmin summer map. I am not sure of the history of how these colors and symbols came into being, but it has never made logical sense to me. And with the limited color variations on the Garmin, providing different shades of the same color simply did not work:

Green (Easy) – This color makes sense and is mostly acceptable to display on the map if you do not use strong shades of green as landcover for parks and forested areas.

Now here is where we run into problems:

Blue (Intermediate) – This makes less sense to me. Why would you choose the color of water to represent the most common trail color? In Trailforks we did our best to mitigate this issue by changing our basemap watercolor to be more of a gray-blue while changing our trails be a more distinct blue. This was not an option on the Garmin, anything blue simply looked more like a river than a trail. Imagine all those trails that travel up and down canyons and hollows. How many follow a river or stream? No version of blue was discernible at a glance and some intersections were even confusing after a long hard stare.

Black (Advanced) – A Black trail has multiple problems.
- Emphasis – To emphasize anything on a thematic map it is most easy for the eye to isolate it when it is the only item in a picture with color. We use this concept heavily in our basemap, and while a thick black line does stand out, it still exists within the grayscale spectrum. So when compared to trails with color, it does not catch your eye the same way.
- Contour Lines – While not available yet we tested our map using transparent backgrounds against a terrain map that employed contour lines. Contour lines on the Garmin are black lines, and with many trails following along with contours, this was also confusing in mountainous areas.
- Night – Our theme works well at night, but it would not have if we used black. Garmin does provide the ability to provide different colors for night, but we wanted consistency between night and day as much as possible.

Black-Black (Expert) – So this is a total mystery to me. Not only is black a less than ideal trail color choice, but the color is already taken. Now your map is required to have some kind of floating icon along the trail to differentiate.

The above standard works good for ski/piste maps, where water is frozen or covered, and the runs are big and wide enough to accommodate big double diamond icons.


My first efforts in tuning this map was to create local extractions, where I tested many trail combinations on the trails around my house. Part of the area is within the US Forest Service boundaries, so I could test how these colors looked on both a plain background and a green forest polygon. Some colors looked great while sitting at my computer, but out on the trail, I could not tell the difference in colors. I tried straight colors, tracks with borders, and even bitmaps with various patterns on many many rides.

Trailforks Basemap for Garmin

But even after trying all these color combinations, and even though I was the one that created the color key, I could often not remember all these different patterns. I had to boil it down to the basic trail colors that stood out the most and provided the most contrast between each other. What I found was that a simple “Severity” system appeared to work the best and provide a simplistic understanding that was easy to remember. Basically, green is the easiest, and the colors become more severe as the trail gets more difficult:

Trailforks Basemap for Garmin
Green (Easy) – Same as the standard, but I had to make it brighter and with a dark outline on the edges to be sure that I could view it easily in daylight while riding on green shaded park polygons.

Yellow (Intermediate) – In a severity system, this is like a minor alarm (not blue), still probably easy, but watch out for some difficult sections, narrow trail, maybe even some exposure.

Orange (Advanced) – This is like a major alarm in a severity system, and provides a nice bright color (not black).

Red (Expert) – This is the same as what we use on Trailforks to denote an Expert trail, because in a tight trail system it is difficult enough to pack in trail labels, much less a floating double diamond icon. Even the red here had to be a bit of a darker red (like maroon), because on the Garmin it was difficult to differentiate between orange and red out on the trail in the mid-day sun.


We wanted to display some important points from the Trailforks database on the map, but with a smaller screen, we did not want to clutter up the map with icons. So we decided to just include the points of interest that really matter. We considered the map as 3 zones: One the trail, at the trailhead, and in town. To keep clutter to a minimum, we only show one POI in each zone. So in town we display bike shops. Trailheads serve as navigation both to the trails and back to your vehicle. When riding out on the trails we display TTFs.

Trailforks Basemap for Garmin

Parking/ Trailheads: The blue dot on the map serves as a great guide to get you to the trailhead when riding your bike from home or a hotel in town. Besides color, our chosen POI markers are shown at high and low zoom levels so that they stand out as you roll into town and are hot to get out on the dirt.

Trailforks Basemap for Garmin

TTF: I like to see a TTF on the trail when I am in a massive trail complex that I know has some jumps, but I can’t remember exactly which track to take. This is common in the desert, where often many trails exist, but if you miss the jump line, you have to pedal back up. Also, a TTF can sometimes be just slightly off the main trail. For this reason, we made this icon an upside-down triangle that points its tip to the exact location. A fat icon has the tendency to obscure the TTF as you approach, not knowing which side of the trail to look for the option.

Bike Shops
Not something I would typically want obscuring a trail, but since these icons remain mostly in town, they don’t clutter up the trail, but come in very handy when tools and an expert hand is required. We placed the bike shop icon at high and low zoom levels so that when you are arriving in a new town, you can easily see where all of them are in relation to you and the local trails. I am sure it never happens to you, but I always seem to forget something I need, and I remember it en route.
Trailforks Basemap for Garmin

Now this was kind of an added bonus. Up until I started testing our new Garmin theme, I could see strava segments that I had starred, except that they were floating around in outer space. I kind of knew where they were, but it wasn't always clear how or exactly when I would get to the start of one because I could not see the trail leading up to the beginning. I had been testing this all through the summer of 2016, but it was only part way through that I started to use the Garmin/Strava feature. One ride after doing a firmware update on my unit, and I noticed some of my favorite Strava DH flowy segments appear right in the context of the trail.
Trailforks Basemap for Garmin


OK, I admit, I do not like riding a fatbike and I like to ride my cyclocross bike on local paved paths, gravel roads, and around town for training purposes. When I ride into the city I don’t remember which roads have a nice shoulder or bike lane, and which roads will probably kill you on site. So to help navigate around town and to trailheads, I added 2 additional colors.

Trailforks Basemap for Garmin
Purple (Paved Paths)
They are thick and bright, and appear to be a highway in comparison to the actual automobile highways, but isn’t that what they are? A highway for bikes should be the most prominent track on a road map for bikes.

Cyan (Bike Lanes)
I love having this layer when I am riding around the city or connecting between two trail systems. It tells me exactly which are the best roads to ride a bike safely on, similar to our Trailforks basemap bike lane theme.

Note: A couple things to keep in mind. First, these are not a collection of courses or jpg images, these are Garmin basemap IMG files. They have to be or else we could never cover such large areas and have the unit tell you which trail you are on. Also each geographic area is calculated based upon the trails in that region with a bit of margin. Some locations this area should maybe be bigger or are even too big. Please keep in mind that this is a first release, and we welcome input that we can incorporate into subsequent releases. Also to improve these maps we suggest contributing to the OpenStreetMap project by lining up roads and dirt roads (tracks). By doing this the Garmin map (and Trailforks Basemap) will be more accurate in showing trail to road connections. The trail & POI data is from the Trailforks database, we will updated the Garmin maps maybe twice a year.


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