How to prepare a race like “Les Roc’h du Mont d’Arrée” in 8 stages with TwoNav tools

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Les Roc’h du Mont d’Arrée is a mountain biking event whose preparation begins many months before the participants set off. For several editions now, TwoNav has collaborated with the organisers, who use Land planning software and GPS devices to prepare and manage the routes. Below, we show you, step by step and with real examples, how the organisers use Land and TwoNav GPS devices to prepare a race like Les Roc’h du Mont d’Arrée.

In the weeks following each edition, once the event has been reviewed, preparations for the next edition of Les Roc’h du Mont d’Arrée begin immediately. For example, work on this year’s edition, held in September 2026, began in October 2025.

Two employees of the CODEP 29 FFVélo mountain biking committee, Malika and Bernard, prepare the next edition alongside members of the various committees, working together as a coordination committee.

Below, we explain, stage by stage, the main uses of Land and TwoNav GPS devices when preparing Les Roc’h du Mont d’Arrée.

Stage 1: Creating the preliminary routes

Starting with a map without any tracks, but with a main idea in mind (for example, in 2026: heading west), the preliminary routes are drawn on a 1:25,000 IGN France map, starting with the 120 km route and finishing with the 20 km route. The tracks take accumulated experience into account: routes from previous years, storms, fires, restricted areas, etc.

To create the tracks more easily and in just a few clicks, the FastTrack feature is used with OpenStreetMap vector mapping overlaid on the 1:25,000 IGN France raster map.

IGN Top25 France map

Stage 2: Checking the area using other maps

As an additional check, a recent orthophoto (aerial view) is used to see whether the terrain has changed significantly over the years.

In addition, a cadastral map helps identify public sections and private plots, as the relevant local councils will need to be contacted to identify the landowners, between 100 and 200 in the case of Les Roc’h du Mont d’Arrée.

Orthophoto and cadastral maps

Stage 3: Recording the final routes

It is now time to check all the routes prepared in Land out on the ground and record the final tracks with a TwoNav GPS. This work allows the organisers to check the condition of the trails and compare what was planned on the map with actual conditions on the ground.

Cross Plus GPS

The recorded tracks are then compared with the preliminary tracks in Land to update and correct the routes. To do this, the organisers use Land features such as splitting tracks, copying and pasting sections, joining tracks, or selecting and deleting groups of points, until the final track is ready.

Stage 4: Printing the routes and elevation profiles

Once the tracks have been updated, the organisers use Land to print each route to PDF separately or create an overview of all the routes.

They also print the elevation profiles for each route to review the changes in elevation. Land allows each point to be viewed both on the map and on the profile, making it easier to identify climbs, descents and their location along the track.

Elevation graph

Stage 5: Marking waypoints

First, R waypoints (refreshment points) are placed near the track. One R point can serve several routes. These allow the refreshment teams to locate the meeting point precisely.

Next, S waypoints (safety points) are placed at certain junctions, with a number of stars proportional to the risk. They allow course marshals to locate their assigned junction precisely.

• 2 stars = essential
• 1 star = useful
• 0 stars = if possible

Then, B waypoints (branching points) and C waypoints (convergence points) are placed where the routes split or merge. They make it easier to install specific signs, manage cut-off times and keep track of the sectors for course marking and sign removal.

B waypoints

Next, PR waypoints (road signs) are placed alongside the road, 150 metres on either side of certain junctions. They make it easier to install and collect the AK 14 road signs used to warn motorists that mountain bikers are crossing.

Finally, P waypoints (watercourse crossings) are placed at watercourse crossings without a permanent bridge or footbridge. They help locate the points where specific arrangements are needed: temporary footbridges, signs, etc.

Timetable

Once the waypoints are ready, the waypoint lists are exported to obtain distances and GPS coordinates. This information is added to various Excel tables:

• Refreshment points
• Timetables
• Opening and closing
• Course marking sectors

Stage 6: Dividing the routes into sectors

The routes are divided into course marking sectors (laps A, B, C, etc.), which are allocated to around a dozen clubs.

Colour-coded sectors

Stage 7: Paper maps

A0 map

A0 maps are created for Saturday and Sunday using high-definition printouts from Land. These two master maps require further manual work to overlay the different routes in colour and the necessary waypoints.

Stage 8: Race day arrives

During the event, all these resources are used particularly to check the course marking, help course marshals reach their posts, support the clubs that manage the refreshment points and assist with sign removal.

In addition, all the tracks and markers prepared are particularly useful to the safety command post and the rescue teams when they need to respond to incidents along the routes.

CODEP 29 FFVélo
CODEP Mountain Biking Committee
Les Roc’h des Monts d’Arrée Subcommittee

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