Prismatic compasses in Brunton and traditional patterns are used for rapid bearing observation in forest traverses, geological mapping and topographic surveys — Multi Trade Combines stocks both types in Guwahati, price on request.
The prismatic compass is one of the oldest and most proven survey instruments, yet remains indispensable for field reconnaissance and rapid-traverse work in terrain where heavier equipment cannot reach. Its operating principle is simple: a magnetised needle floating on a sapphire bearing aligns to magnetic north, and a prism eyepiece allows the surveyor to read the graduated circle against a distant target simultaneously — achieving a magnetic bearing to the target without the need for any secondary calculation.
Multi Trade Combines carries both the traditional cylindrical prismatic compass for bearing traverses and the Brunton pocket-transit style, which adds clinometer and mirror-sight capability for geological and mining applications. Both types are housed in protective carrying pouches and are supplied with a lanyard for neck carry during extended field work in Northeast India's rugged terrain.
The Geological Survey of India (GSI) field teams mapping Assam, Meghalaya, Nagaland and Arunachal Pradesh carry Brunton compasses as standard personal equipment alongside GPS receivers. Forest department rangers conducting boundary and encroachment surveys in reserved forests use traditional prismatic compasses for rapid bearing-and-distance traverses. Mining permit holders in Meghalaya's coal and limestone belts use prismatic compasses for claim area surveying. Hydrology teams mapping drainage basins and watershed areas across Northeast India's hilly states include prismatic compasses in their standard field kit. Our central Guwahati location makes us a resupply point for field teams returning from remote assignments.
For a complete manual field survey kit, pair the prismatic compass with a plane table and alidade from our surveying range — the plane table gives graphic survey capability without digital equipment. The auto level and dumpy level in our range complement the compass for elevation work on the same traverse. For longer-range or higher-precision surveys, our total station and digital theodolite complete the instrument suite. A Bosch laser distance meter can replace the steel tape for quick distance shots in accessible terrain.
| Category | Surveying Instruments |
|---|---|
| Key specs | Brunton & traditional |
| Models | Traditional prismatic, Brunton pocket transit |
| Scale | 0–360° graduated circle |
| Features | Prism eyepiece, sighting vane, protective case |
| Availability | In stock — price on request |
More from our Surveying Instruments range
A total station is a precision instrument requiring tripod setup, levelling and battery power — not always practical in dense forest, steep terrain or rapid reconnaissance surveys. A prismatic compass gives a bearing reading in seconds, hands-free, with no setup time and no power requirement. Forest department survey teams mapping reserve boundaries in Assam and Arunachal Pradesh often use a prismatic compass for preliminary traverses before deploying heavier equipment. Geological survey teams on rock-face reconnaissance carry a Brunton pocket transit — essentially a sophisticated prismatic compass — for strike and dip measurements that a total station cannot provide.
A traditional prismatic compass (also called a surveying compass or lensatic compass) is a cylindrical brass or aluminium body with a prism eyepiece that allows simultaneous sighting of the target and reading the graduated compass ring — both in one view. A Brunton compass (pocket transit) adds a clinometer (for vertical angle/slope measurement), a level bubble and a folding mirror sight, making it a multi-function instrument suited for geological work. Traditional prismatic compasses are more economical and widely used for general bearing traverses; Brunton-type instruments serve geologists, miners and hydrologists needing slope data alongside bearing.