Free Photogrammetric Data Acquisition Questions and Answers

Question 1

What is the main purpose of photogrammetric data acquisition?

Accepted Answer

Mapping and measurement

Answer

The main purpose of photogrammetric data acquisition is to obtain precise measurements and create accurate maps or 3D models of objects and terrain. By using photographs, photogrammetry allows for the extraction of geometric information, which is crucial for applications in surveying, engineering, and geographic information systems (GIS).

Question 2

Which type of camera is commonly used in aerial photogrammetry?

Accepted Answer

Metric camera

Answer

A metric camera is specifically designed for photogrammetric applications due to its high geometric stability and precisely calibrated internal parameters. Unlike consumer cameras, metric cameras minimize lens distortions and provide accurate focal length and principal point information, which are essential for precise measurements and mapping. This ensures the geometric integrity required for photogrammetric processing.

Question 3

What is the term for the area captured in a single aerial photograph?

Accepted Answer

Ground coverage

Answer

Ground coverage refers to the actual area on the Earth's surface that is captured within a single aerial photograph. This area is determined by factors such as the camera's focal length, the sensor size, and the flight altitude. Understanding ground coverage is essential for planning flight paths and ensuring complete area mapping.

Question 4

Which factor most influences the scale of an aerial photograph?

Accepted Answer

Flight altitude

Answer

The flight altitude is the most significant factor influencing the scale of an aerial photograph. A higher flight altitude results in a smaller scale photograph, meaning a larger ground area is covered but with less detail. Conversely, a lower flight altitude produces a larger scale photograph, showing more detail over a smaller ground area.

Question 5

What is the overlap percentage typically required between consecutive aerial photos?

Accepted Answer

60%

Answer

A 60% overlap (forward lap) between consecutive aerial photos is a standard requirement in photogrammetry. This significant overlap ensures that every point on the ground is visible in at least two, and often three, images, which is crucial for creating stereoscopic models. This redundancy allows for accurate aerotriangulation, the generation of precise digital elevation models (DEMs), and the production of seamless orthophotos without gaps.

Certified Photogrammetrist Practice Test

Certified Photogrammetrist Practice Test

Free Photogrammetric Data Acquisition Questions and Answers