Compass Surveying

A chain or tape is used for linear measurements and compass is used for fixing direction in Compass Surveying. In compass north-south is directed by freely suspended magnetic needle and line of sight helps to obtain the bearing. The various instruments helpful in compass surveying are prismatic compass, Tape and ranging rods.

Prismatic Compass

The prismatic compass uses a small capsule packed with oil and a dial which is magnetized. This arrangement is amplified with an illumination component. With the help of this component, compass reading of all types with most accurate measurement can be calculated. Prismatic compass sometimes referred to as an optical compass, provides exact measures and the pinpoint accuracy of this device helps to make prismatic compasses important for a number of developments. The prismatic compass makes it easy to segregate a bearing from any point on the surface of earth. The pointer within the device helps to sustain with the pull of the natural magnetic field of the earth, and thus the compass helps in determining the basic directions, that is, east, west, south and north. The prismatic compass is designed in such a way that it can handle heavy-duty use. Many models of the prismatic compass are developed in such a way that it can mount tripod when apt, and held and operated in one hand. Some prismatic compasses are illuminated with the assistance of a small battery; some others are equipped with photo luminescent materials to make the dial observable in low light environments. Centering, leveling and focusing the prism are the major adjustments necessary in prismatic compass.

Surveying compasses without Protractor base

These instruments have fluctuating needle card with scale and optical reading. They are suitable and accurate for surveying and it will be very effective for forest road surveys. The readings in this will accurate to 0.5 degrees. The vertical index lines appear to project above the compass case with the help of optical chimera. The index line should be aligned to attain a particular target and when reading the bearing both eyes must be kept open as one cannot see through the instrument.

 Compass engineering Surveying

Compass Engineering is playing a very vital role in professional Civil Engineering, Surveying, and planning services. Compass Engineering comprises of a team of senior-level civil engineers and designers with broad expertise in all aspects of public works .They help in private development engineering.

Questions:

• What is meant by compass surveying?
• What are the instruments used in compass surveying?