Introduction to Orienteering
Lesson 3: Thumbing the Map
By Anthony Scott, 2020
To help the orienteer keep in contact with their location on the map, it is essential that they do three basic things at all times:
1. Fold the map to make it easier to hold and read. This may need to be done constantly as new sections of the map come into consideration.
2. Keep the map orientated at all times, i.e. align north on the map to north in the field.
3. “Thumb” the map. Means that you grip the map with your thumb just below the exact spot where you are. This is a very simple but effective way of avoiding a common mistake – reading the wrong part of the map. (If you use a thumb compass, thumb the map with the pointed tip of the compass plate.) Because you have to constantly glance up from the map to the terrain and back, and because there are many similar-looking features on the map – it is easy to mistakenly start reading the wrong part of the map, with disastrous results. This is called a parallel error.
Map folded and oriented to north. Thumb placed on the map, at the place where you are, half way between the start and control 1. Think ahead – track gently bending right and heading up hill. Control is on top of the ridge, after a left hand bend in the track.
The essence of success in orienteering is to maintain contact with the map, always knowing exactly where you are. Moving your thumb along the map as you move through the terrain, helps you keep this contact.
Think ahead, read both the map and the terrain, moving your thumb along the map as you pass the major features.