A thumb compass is a type of

compass A compass is a device that shows the cardinal directions used for navigation and geographic orientation. It commonly consists of a magnetized needle or other element, such as a compass card or compass rose, which can pivot to align itself wit ...

commonly used in orienteering, a sport in which map reading and terrain association are paramount. In cases of homogeneous terrain with few distinct features, a bearing between 2 known points on the map may be used. Consequently, most thumb compasses have minimal or no degree markings at all, and are normally used only to take bearings directly from a map, and to orient a map to magnetic north. Thumb compasses are also often

transparent Transparency, transparence or transparent most often refer to: * Transparency (optics), the physical property of allowing the transmission of light through a material They may also refer to: Literal uses * Transparency (photography), a still, ...

so that an orienteer can hold a

map A map is a symbolic depiction emphasizing relationships between elements of some space, such as objects, regions, or themes. Many maps are static, fixed to paper or some other durable medium, while others are dynamic or interactive. Although ...

in the hand with the compass and see the map through the compass. Thumb compasses attach to one's thumb using a small

elastic Elastic is a word often used to describe or identify certain types of elastomer, elastic used in garments or stretchable fabrics. Elastic may also refer to: Alternative name * Rubber band, ring-shaped band of rubber used to hold objects togeth ...

band. The first commercially successful orienteering thumb compass was the Norcompass, introduced by Suunto in 1983. Placing an even greater emphasis on speed over accuracy, the wrist compass lacks even a baseplate, consisting solely of a needle capsule strapped to the

carpometacarpal joint The carpometacarpal (CMC) joints are five joints in the wrist that articulate the distal row of carpal bones and the proximal bases of the five metacarpal bones. The CMC joint of the thumb or the first CMC joint, also known as the trapeziometaca ...

at the base of the thumb; the thumb serves the function of a baseplate when taking and sighting bearings. It is often used for city and park race orienteering.

References

External links

Silva 6 Jet Spectra
a typical modern thumb compass
The Internet Compass Museum
gives comprehensive information about all sorts of compasses and how to use them. Orienteering Sports equipment {{Orienteering-stub

See also

References

External links