Prismatic Compass
Product Code : EL-SLE-10986
Prismatic Compass (code EL-SLE-10986) is a magnetic compass used in compass surveying to find the direction of survey lines, while their lengths are measured with a chain, tape or laser range finder. It takes its name from the prism through which observations are taken, and it is generally used to run traverse lines by reading the bearing of each line from the magnetic needle.
Get a quote: use the Add To Cart enquiry button below, or send your quantity and delivery location through the contact page.
Specifications
| Parameter | Detail |
|---|---|
| Use | Determining the directions of survey lines; running traverse lines |
| Direction reference | Magnetic needle |
| Sighting | Prism for taking observations |
| Bearings | Fore bearing and back bearing taken for each line of a traverse |
| Product code | EL-SLE-10986 |
| Manufacturer | Engineering Lab Equipment, Ambala, Haryana, India |
What Is the Prismatic Compass Used For?
In compass surveying the surveyor sets the compass up over a station, sights the next station through the prism and reads the bearing of the line, its angle from magnetic north as shown by the needle. A fore bearing is taken looking forward along each line and a back bearing from its far end; the two should differ by exactly 180 degrees, and any other result points to local magnetic attraction or a reading error. The included angles of the traverse are then calculated from the bearings, using the formulas for clockwise or anti-clockwise traverses.
What to Specify When Ordering
- Quantity — the number of compasses required.
Frequently Asked Questions
Why is it called a prismatic compass?
It contains a prism through which observations are taken, and it is this prism that gives the instrument its name.
What is the compass used for?
It is used to find the directions of survey lines with a magnetic needle and generally to run a traverse, while line lengths are measured with a chain, tape or laser range finder.
How are fore and back bearings checked?
For each traverse line a fore bearing and a back bearing are taken; the two should differ by exactly 180 degrees, and any other difference shows an error or local attraction to be investigated.
Are angles between lines found with the compass?
The compass reads the bearing of each line from the magnetic needle, and the included angles of the traverse are calculated from those bearings for clockwise or anti-clockwise traverses.
OEM Manufacturer
The Prismatic Compass is made by Engineering Lab Equipment (Engineering Labs Equipment Pvt Ltd) at its works at Plot No. 43, Industrial Park, Sector 2, Growth Center, Saha, District Ambala, Haryana, India. The company designs, makes and tests surveying instruments and accessories for engineering colleges, polytechnics, technical training institutes and research laboratories in India and overseas, and can build equipment to an institution's own requirements. Tender and OEM enquiries are handled through the Tenders/OEM page.
Related Surveying Equipment
- Square Hole Form — concrete hole form leaving a 4" x 4" square opening, aligned and stripped by its tab.
- Plane Table Set — field mapping table set with a telescopic sight alidade for plotting survey lines.
- Corner Guard — edge protector for 4" straps or chains that stops chipping and scarring of concrete.
- Total Station — 2" reflector-less total station measuring up to 200 metres without a prism, with target tracking.
- Prism with Pole — 25.4 mm tilting survey prism on threaded pole sections with 30 mm circular vial.
See the full Surveying Lab Equipment range or all Civil Engineering Lab Equipment.
Request a Quote
For this and other surveying lab equipment, schools and colleges can contact Engineering Lab Equipment, a manufacturer, supplier and exporter based in Ambala, India. To ask for a quotation, send the number of prismatic compasses required and your delivery location through the contact page, or use the Add To Cart enquiry button on this page.
Last updated: October 2026
