Surveying Note for GATE PSUs | part 4

Hello there,
Here is another post for your preparation for the GATE and PSUs examinations.

• A gate cap is fitted with a prismatic compass
• The temporary adjustments of a prismatic compass are Centering, Leveling, and Focusing the prism respectively in order.
• Swinging is the process of turning the telescope about the vertical axis in the horizontal plane.
• The size of a Theodolite is specified by the diameter of the lower plate.
• If the lower clamp screw is tightened and the upper clamp screw is loosened, the Theodolite may be rotated on its inner spindle with a relative motion between the vernier and the graduated scale of the lower plate.
• A telescope is said to be inverted if its vertical circle is to its right and the bubble of the telescope is down.
• The crosshairs in the surveying telescope are placed much closer to the eye-piece than the objective piece.
• For the adjustment of the horizontal axis, the spire test is used for its permanent adjustment.
• The adjustment of the horizontal crosshair is required when the instrument is used for leveling.
• Error due to displacement of the station signal can not be eliminated by the repetition method of angle measurement.
• The error due to the eccentricity of inner and outer axes can be eliminated by reading both verniers and taking the mean of the two.
• In the double application of the principle of reversion, the apparent error is four times the true error.
• Error due to line of collimation not being perpendicular to the horizontal line can be eliminated by taking a mean of both face observations.
• If a tripod settles in the interval that elapses between taking a back sight-reading and the following foresight reading, then the elevation of the turning point will increase.
• If altitude bubble is provided both on index frame as well as on telescope of a theodolite, then the instrument is leveled with reference to altitude level on the index frame or altitude level on telescope if it is to be used as a level.
• A 'level line' is a line parallel to the mean spheroidal surface of the earth.
• The turning point is the station where both back sight and fore-sights are taken
• A rise and fall method provides us check on back-sights, foresight as well as on intermediate sights.
• In the internal focusing type of telescope, a concave lens is provided.

Thanks for your visit!

References:

Civil Engineering Through Objective by S. P. Gupta 

ESE 2021 by IES Master