FUNDAMENTAL SURVEYING Surveying Equipment and Technology 2

Question 1

What is 'photogrammetry' in the context of surveying?

Accepted Answer

The science of deriving reliable measurements and 3D models from photographs

Answer

The science of measuring distances with a camera flash

Answer

The use of satellites for position determination

Answer

A method of sonar-based underwater surveying

Question 2

What is the main purpose of ground control points (GCPs) in drone photogrammetry?

Accepted Answer

To georeference the photogrammetric model to a known coordinate system with accurate ground coordinates

Answer

To provide landing zones for the drone

Answer

To calibrate the camera's focal length

Answer

To block obstructions in the flight path

Question 3

What is the difference between absolute accuracy and relative accuracy in surveying?

Accepted Answer

Absolute accuracy describes position accuracy relative to a datum; relative accuracy describes position accuracy between points in the survey

Answer

Absolute accuracy is always higher than relative accuracy

Answer

Relative accuracy uses GPS; absolute accuracy uses total stations

Answer

They are the same concept

Question 4

What is 'ground sampling distance' (GSD) in drone photogrammetry?

Accepted Answer

The size of one pixel on the ground in a drone image

Answer

The horizontal distance between drone flight lines

Answer

The depth of penetration of LiDAR pulses

Answer

The distance between GCPs

Question 5

What is the purpose of a 'prism constant' applied to total station measurements?

Accepted Answer

To compensate for the physical offset between the prism center and the reflecting face

Answer

To correct for atmospheric refraction

Answer

To account for instrument tilts

Answer

To correct for Earth curvature

Question 6

Which GNSS constellation is operated by the United States government?

Accepted Answer

GPS (NAVSTAR)

Answer

GLONASS

Answer

Galileo

Answer

BeiDou