Hiking – How to use an IGN map when hiking?
IGN maps, like treasure maps, remain a mystery to most hikers. We reveal the key steps to follow to learn how to read an IGN map and make the most of your hiking trip.
Step 1 – Understanding scale and legend
On IGN maps, produced by the Institut National de l'Information Géographique et Forestière, the cover page provides a first level of information. The title, subject, scale and GPS compatibility (for certain editions) are all indicated. Depending on the scale, the information on the map will be more or less detailed.
For hiking maps, the scale is most commonly 1:25,000. This level of detail makes it possible to indicate the nature and features of the terrain — trails, watercourses, roads and communication routes, and relief.
On the institute's website, scale is defined as follows: "it is the reduction ratio between the cartographic representation and the terrain." This concept allows you to convert a length measured on the map to the actual distance on the ground. For a concrete example, refer to the video with mountain guide Florian Olivier, who also provides further explanations on:
- contour lines,
- spot heights,
- legend symbols, etc.
Step 2 – Knowing how to locate yourself on the map
Then, when hiking with an IGN map, it is important to know your position on your topographic map.
To position yourself accurately, you'll need to sharpen your observation skills and rely on the landmarks around you: watercourses, summits, paths or trails, buildings and other man-made structures.
Watch more detailed examples in the video below.
Step 3 – Orienting your IGN map correctly
Finally, to make proper use of your map in the field, learn how to orient it — an exercise that is not complicated. Especially since on an IGN map, the North indicated corresponds to the left or right edges of the map.
Two options are then available to hikers:
- If you have a compass: align a meridian (black line on the map) with your compass needle.
- If you know your position: identify on the map a point easily recognisable on the ground, such as a church steeple, a building, a mountain. Then rotate your map to point towards the chosen landmark. For added reliability, you can check the orientation by sighting a second reference point.
Find more explanations in the video. Check out how to prepare for hiking in the rain.
Photos ©Cyrille Quintard ©Focus-Outdoor
