Free Remote Sensing & Image Interpretation Questions and Answers

Question 1

What is remote sensing primarily used for in photogrammetry?

Accepted Answer

Capturing spatial information from a distance

Answer

Remote sensing is the process of acquiring information about an object or phenomenon without making physical contact with it, typically using sensors on aircraft or satellites. In photogrammetry, it specifically involves capturing aerial or satellite images to derive spatial data, such as measurements, maps, and 3D models. It allows for broad-scale data collection from a distance.

Question 2

Which type of satellite sensor detects reflected sunlight?

Accepted Answer

Passive sensor

Answer

Passive sensors detect and measure natural radiation that is reflected or emitted from the Earth's surface, such as sunlight or thermal energy. They do not generate their own energy source, relying instead on ambient energy, making them dependent on external illumination like the sun. Examples include traditional cameras and many satellite imagers.

Question 3

What is the term for the smallest object that can be detected by a sensor?

Accepted Answer

Spatial resolution

Answer

Spatial resolution refers to the size of the smallest feature on the ground that can be distinctly detected and represented by a sensor's pixel. A higher spatial resolution means smaller pixels, allowing for the detection of finer details and smaller objects on the Earth's surface. It dictates the level of detail visible in an image.

Question 4

Which color band is most effective for detecting healthy vegetation?

Accepted Answer

Near-infrared band

Answer

Healthy vegetation strongly reflects near-infrared (NIR) light due to the cellular structure of its leaves, while absorbing most visible red light for photosynthesis. This distinct spectral signature makes the near-infrared band highly effective for distinguishing healthy vegetation from other land cover types and assessing plant vigor, biomass, and stress levels.

Question 5

Which type of remote sensing uses emitted microwave energy to collect data?

Accepted Answer

Active radar sensors

Answer

Active radar sensors, such as Synthetic Aperture Radar (SAR), emit their own microwave energy pulses and then measure the reflected signal. This allows them to collect data independently of natural illumination and through atmospheric conditions like clouds or smoke. This capability makes them valuable for all-weather, day-and-night remote sensing applications.

Certified Photogrammetrist Practice Test

Certified Photogrammetrist Practice Test

Free Remote Sensing & Image Interpretation Questions and Answers