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

Photogrammetry extracts metric measurements, elevations, and 3D models from overlapping photographs using principles of geometry.

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

GCPs are surveyed points with known coordinates placed in the project area to georeference and improve the accuracy of the photogrammetric model.

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 measures how close a position is to its true location on the datum, while relative accuracy measures how precisely positions relate to each other within the survey.

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

GSD is the real-world distance represented by a single pixel in a drone image, determining the spatial resolution of the final orthophoto and DEM.

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

The prism constant corrects for the physical distance between the reflective face of the prism and its center (pole mounting point), ensuring measured distances are to the ground point.

FUNDAMENTAL SURVEYING Practice Test

FUNDAMENTAL SURVEYING Practice Test

FUNDAMENTAL SURVEYING Surveying Equipment and Technology 2