SHOTS - SURVEYING
💥 Theory of probability applied to accidental error only.
💥 The difference between the most probable value and its observed value is residual error.
💥 The difference between the most probable value and its observed value is residual error.
💥Geodetic surveying is different from plane surveying because curvature of the earth is considered.
💥 The error due to bad ranging is cumulative positive.
💥 Offsets are short measurements from chain line.
💥 Invar tape is generally used for short measurements.
💥 An invar tape is made of an alloy of nickel and steel.
💥 Number of links in a 30m chain are 150.
💥 Ranging is the process of aligning the chain in a straight line between two extremities.
💥 The principle of ‘working from whole to part’ is used in surveying because of accumulation of errors can be prevented.
💥 A metallic tape is made of cloth and wires.
💥 For a well conditioned triangle no angle should not be less than 30* and not more than 120*.
💥 The position of a point can be fixed more accurately by perpendicular offsets.
💥 The main object of check line is check the accuracy of the work and the main object of tie line is to take the details near by the objects.
💥 River is an obstacle to chaining but not ranging.
💥 A building is obstacle to both ranging and chaining.
💥 The angle of intersection of the two plane mirrors of an optical square is 45*.
💥 45* angle is used to setup using French cross staff and any angle is set up using adjustable cross staff.
💥 Method of perpendicular offsets involves less measurements on the ground.
💥 The correction for sag is always subtractive.
💥 Cross staff is an instrument used for setting out right angles.
💥 Line ranger is not used in measuring the perpendicular offsets.
💥 If the length of the chain is found to be short on testing it can be adjusted by straightening the links.
💥 The maximum tolerance in a 20m chain is 5mm.
💥 For accurate work steel band is used because it is practically in-extensible and is not liable to kinks when in use.
💥 The length of the chain is measured from outside of one handle to outside of another handle.
💥 Prismatic compass used for WCB and surveyor compass used for QB.
💥 For a line AB the fore bearing of line AB and back bearing of AB exactly differ by 180*.
💥 Local attraction in compass surveying may exist due to presence of magnetic substance near the instrument.
💥 Declination-the horizontal angle between the true meridian and magnetic meridian.
💥 Azimuth-the angle between the true meridian and a line.
💥 Dip-horizontal angle with respect to inclination of dip of the needle.
💥 Agate cap is fitted with a prismatic compass.
💥 Theodolite is an instrument used for measuring the both horizontal and vertical angles.
💥 Size of the theodolite is specified by the diameter of lower plate.
💥 Spire test is used for adjustment of horizontal axis.
💥 A level line is a line parallel to the mean spheroid surface of the earth.
💥 On turning point both back sight and fore sights taken.
💥 rise and fall method of levelling provides complete check on BS FS and IS.
💥 Height of the instrument method is less tedious and quicker.
💥 The sensitivity of a bubble tube can be increased by increasing the diameter of the tube.
💥 While doing the levelling in undulating terrain it is preferable to set the level on one side of the slope.
💥 Dumpy level is suitable when many readings are to be taken from single station.
💥 A series of closely spaced contours called steep slope.
💥 Direct method of contouring is more accurate.
💥 Tachometric method is most suitable for hilly terrain.
💥 Hillock-higher values inside lower values are outside.
💥 Valley-higher values are outside and lower values are inside.
💥 Contour interval-the vertical distance between the two consecutive contours.
💥 Benchmark is established by spirit levelling.
💥 Plane table surveying require least office work.
💥 Detailed plotting is generally done by radiation.
💥 The size of plane table is 600mm*750mm.
💥 Plumbing fork is used for accurate centering in plane table survey.
💥 Intersection method is used for locate the position of inaccessible points.
💥 The two point and three point problem are the methods of orientation and resection.
💥 Bowditch rule is used when both angular and linear measurements are equal.
💥 Transit rule is used when angular measurements are more precise than linear measurements.
💥 Deflection angle-the angle between the prolongation of preceding line and the forward line.
💥 Substance bar used for measurement of horizontal distance in undulated areas.
💥 Over turning of a vehicle can be avoided by providing transition curves.
💥 Different grades are joined together by vertical curve.
💥 The shape of the vertical curve generally provided is parabolic.
💥 Agonic line is the line joining the points of zero declination.
💥 Altimeter-height measuring,
💥 fathometer-depth measuring,
💥 passometer-distance measuring.
💥 Clino meter-angle measuring,
💥 pantograph-plan enlarging or reducing,
💥 tellurometer-microwave instrument.
💥 Offsets are lateral measurements made with respect to the main survey line.
💥 To determine the length of the bridge triangulation is used.
💥 Heliograph is a type of sun signal is used in triangulation work.
💥 Topographical surveying-to determine the natural features of the country.
💥 Cadastral surveying-to determine the boundaries of field.
💥 City survey-to determine the railway, drainage, road features of the country.
💥 The fix of a plane table from three known points is good if the middle station is nearest.
💥 Plane alidade is used to measure the horizontal and vertical distances directly.