Surveying Methods & Techniques Flashcards

Which triangulation figure provides the strongest network geometry and is used in primary control surveys?

Answer: Braced quadrilateral

The braced quadrilateral (four sides and both diagonals) provides redundant angle observations and strong geometry, making it the preferred figure for primary triangulation networks.

In GPS surveying, the term 'PDOP' refers to:

Answer: Position Dilution of Precision

PDOP (Position Dilution of Precision) is a dimensionless factor that quantifies the effect of satellite geometry on the combined horizontal and vertical position accuracy.

The figure-closure condition in a triangulation network requires that the sum of angles in each triangle equal:

Answer: 180°00'00"

Each plane triangle in a triangulation network must satisfy the geometric condition that its three interior angles sum to exactly 180°00'00".

When running a differential level circuit, the purpose of using equal backsight and foresight distances is to eliminate the effect of:

Answer: Curvature of the earth and atmospheric refraction

Balancing backsight and foresight distances cancels systematic errors due to earth curvature and atmospheric refraction, since both affect the readings equally.

A surveyor sets up a total station and measures a horizontal angle of 47°32'18" to point A and 112°15'44" to point B. What is the angle between the two directions?

Answer: 64°43'26"

The angle between A and B is 112°15'44" − 47°32'18" = 64°43'26".

In plane-table surveying, the method where the instrument is set up at the unknown point and oriented by sighting known points is called:

Answer: Resection (three-point problem)

The three-point problem (resection) on a plane table involves locating the table's position by drawing rays from three known points visible on the sheet without moving the table.

During a GPS static survey, a minimum of how many satellites must be simultaneously observed to obtain a 3D position fix?

Answer: 4

A minimum of four satellites are required for a 3D GPS position fix: three satellites determine position in three spatial dimensions and a fourth resolves the receiver clock error.