A hand compass is a term for any compact magnetic compass

Compass

A compass is a navigational instrument that shows directions in a frame of reference that is stationary relative to the surface of the earth. The frame of reference defines the four cardinal directions – north, south, east, and west. Intermediate directions are also defined...

 capable of one-hand use and fitted with a sighting device to record a precise bearing

Bearing (navigation)

In marine navigation, a bearing is the direction one object is from another object, usually, the direction of an object from one's own vessel. In aircraft navigation, a bearing is the actual compass direction of the forward course of the aircraft...

 or azimuth to a given target or to determine a location. Hand or sighting compasses include instruments with simple notch-and-post alignment ("gunsights"), prismatic

Prism (optics)

In optics, a prism is a transparent optical element with flat, polished surfaces that refract light. The exact angles between the surfaces depend on the application. The traditional geometrical shape is that of a triangular prism with a triangular base and rectangular sides, and in colloquial use...

 sights, direct or lensatic sights,, and mirror/vee (reflected-image) sights. With the additional precision offered by the sighting arrangement, and depending upon construction, sighting compasses provide increased accuracy when measuring precise bearings to an objective.

The term hand compass is used by some in the forestry and surveying professions to refer to a certain type of hand compass optimized for use in those fields, also known as a forester or cruiser compass. A hand compass may also include the various one-hand or 'pocket' versions of the surveyor's or geologist's transit

Brunton compass

A Brunton compass, properly known as the Brunton Pocket Transit, is a type of precision compass made by Brunton, Inc. of Riverton, Wyoming. The instrument was patented in 1894 by a Canadian-born Colorado geologist named David W. Brunton. Unlike most modern compasses, the Brunton Pocket Transit...

.

History and use

While small portable compasses fitted with mechanical sighting devices have existed for a few hundred years, the first one-hand compass with a sighting device appeared around 1885. These soon evolved into more elaborate and specialized models such as the Brunton Pocket Transit patented in 1894. Hand compasses were soon widely employed in the practice of forestry

Forestry

Forestry is the interdisciplinary profession embracing the science, art, and craft of creating, managing, using, and conserving forests and associated resources in a sustainable manner to meet desired goals, needs, and values for human benefit. Forestry is practiced in plantations and natural stands...

, geology

Geology

Geology is the science comprising the study of solid Earth, the rocks of which it is composed, and the processes by which it evolves. Geology gives insight into the history of the Earth, as it provides the primary evidence for plate tectonics, the evolutionary history of life, and past climates...

, archaeology

Archaeology

Archaeology, or archeology , is the study of human society, primarily through the recovery and analysis of the material culture and environmental data that they have left behind, which includes artifacts, architecture, biofacts and cultural landscapes...

, speleology

Speleology

Speleology is the scientific study of caves and other karst features, their make-up, structure, physical properties, history, life forms, and the processes by which they form and change over time...

, preliminary cartography

Cartography

Cartography is the study and practice of making maps. Combining science, aesthetics, and technique, cartography builds on the premise that reality can be modeled in ways that communicate spatial information effectively.The fundamental problems of traditional cartography are to:*Set the map's...

 and land surveying.

In the United States, the hand compass became very popular among foresters seeking a compass to plot and estimate stands of timber. While the Pocket Transit was more than adequate for such work, it was relatively expensive. Consequently, a new type of hand compass was introduced: the forester or cruiser compass. Traditionally, cruiser compasses featured a sighting notch, a mechanically-damped or "dry" needle, adjustable declination and a large dial marked in individual degrees using counterclockwise calibration (reversed east and west positions). A screw base for a tripod

Tripod

A tripod is a portable three-legged frame, used as a platform for supporting the weight and maintaining the stability of some other object. The word comes from the Greek tripous, meaning "three feet". A tripod provides stability against downward forces, horizontal forces and moments about the...

 or jacob staff (monopod

Monopod

A monopod, also called a unipod, is a single staff or pole used to help support cameras, video cameras, binoculars, rifles or other precision instruments in the field.-Camera and imaging use:...

) was often fitted as well.

By the late 1960s many foresters had begun using more modern liquid-damped compass designs, including mirror-sight protractor models such as the Silva Type 15 Ranger

Silva compass

Silva compass, or Silva of Sweden, aka Silva Sweden AB is an outdoors products company, most known for their high-grade compasses and other navigational equipment including GPS tools, mapping software, and altimeters for aircraft. They also offer a marine range...

or the Suunto MC-1

Suunto

Suunto Oy, based in Finland, is a company that produces and markets sports precision instruments for Diving, Training and Outdoor sports. Headquartered in Vantaa, Suunto employs more than 500 people worldwide, and its products are sold in over 100 countries...

(later, the MC-2). These compasses were fast to use, particularly along straight cruise lines and were sufficiently accurate for most forestry applications. On the other hand, geologists, speleologists, archaeologists, ornithologists

Ornithology

Ornithology is a branch of zoology that concerns the study of birds. Several aspects of ornithology differ from related disciplines, due partly to the high visibility and the aesthetic appeal of birds...

, and foresters engaged in precision survey work often used direct-reading models such as the Suunto KB-14, prismatic compasses such as Suunto KB-77 or the traditional Brunton Pocket Transit. Many models featured an optional quadrant

Quadrant

Quadrant may refer to:* A sector equal to one quarter of a circle, or half a semicircle, see Circular sector* The sectors of a two-dimensional cartesian coordinate system, see Cartesian coordinate system#Quadrants and octants...

 (0-90-0 degree) scale instead of an azimuthal (0-360 degree) system.

By using a hand compass in combination with aerial photographs and maps a person can determine his/her location in the field, determine direction to landmarks or destinations, estimate distance, estimate area, and find points of interest (marked boundary lines, USGS marker, plot centers). For increased accuracy, many professional hand compasses continue to be fitted with tripod

Tripod

A tripod is a portable three-legged frame, used as a platform for supporting the weight and maintaining the stability of some other object. The word comes from the Greek tripous, meaning "three feet". A tripod provides stability against downward forces, horizontal forces and moments about the...

 mounts. While the hand compass continues to be widely employed in such work, it has been increasingly supplanted in recent years by use of the GPS, or Global Positioning System

Global Positioning System

The Global Positioning System is a space-based global navigation satellite system that provides location and time information in all weather, anywhere on or near the Earth, where there is an unobstructed line of sight to four or more GPS satellites...

 receiver.

Marine hand bearing compass

The marine hand compass, or hand-bearing compass as it is termed in nautical use, has been used by small-boat or inshore sailors since at least the 1920s to keep a running course or to record precise bearings to landmarks on shore in order to determine position via the resection

Resection (orientation)

Resection is a method for determining a position using a compass and topographic map .-Resection versus intersection:...

 technique. Instead of a magnetized needle or disc, most hand bearing compasses feature liquid damping with a floating card design (a magnetized, degreed float or dial atop a jeweled pivot bearing). Equipped with a viewing prism, the hand bearing compass allows instant reading of forward bearings from the user to an object or vessel, and some provide the reciprocal bearing as well. Modern examples of marine hand bearing compasses include the Suunto KB-14 and KB-77, and the Plastimo Iris 50. These compasses frequently have battery-illuminated or photoluminescent degree dials for use in low light or darkness.