Surveying Equipment and Technology Flashcards
6 cards from real FUNDAMENTAL SURVEYING practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Surveying Equipment and Technology flashcards as text
What is 'photogrammetry' in the context of surveying?
Answer: The science of deriving reliable measurements and 3D models from photographs
Photogrammetry extracts metric measurements, elevations, and 3D models from overlapping photographs using principles of geometry.
What is the main purpose of ground control points (GCPs) in drone photogrammetry?
Answer: To georeference the photogrammetric model to a known coordinate system with accurate ground coordinates
GCPs are surveyed points with known coordinates placed in the project area to georeference and improve the accuracy of the photogrammetric model.
What is the difference between absolute accuracy and relative accuracy in surveying?
Answer: Absolute accuracy describes position accuracy relative to a datum; relative accuracy describes position accuracy between points in the survey
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.
What is 'ground sampling distance' (GSD) in drone photogrammetry?
Answer: The size of one pixel on the ground in a drone image
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.
What is the purpose of a 'prism constant' applied to total station measurements?
Answer: To compensate for the physical offset between the prism center and the reflecting face
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.
Which GNSS constellation is operated by the United States government?
Answer: GPS (NAVSTAR)
GPS (Global Positioning System / NAVSTAR) is operated by the US Department of Defense, one of four major global satellite navigation systems.