GIS Remote Sensing and Imagery 5

Question 1

Which accuracy assessment metric accounts for the possibility of chance agreement between classified and reference data?

Accepted Answer

Kappa coefficient

Answer

The Kappa coefficient (κ) adjusts overall accuracy for the agreement that could occur by chance, providing a more rigorous measure of classification quality.

Question 2

In object-based image analysis (OBIA), what is the first step before classification?

Accepted Answer

Image segmentation to create homogeneous objects

Answer

OBIA begins with image segmentation, which groups adjacent pixels with similar spectral, spatial, and textural properties into discrete objects before classification.

Question 3

What is the main advantage of using a sun-synchronous orbit for Earth observation satellites?

Accepted Answer

The satellite passes over any given location at the same local solar time, ensuring consistent illumination

Answer

Sun-synchronous orbits are designed so the satellite crosses the equator at the same local solar time on every pass, minimizing illumination variation between acquisitions.

Question 4

What does the term 'orthorectification' correct for in aerial and satellite imagery?

Accepted Answer

Displacement of features caused by terrain relief and sensor geometry

Answer

Orthorectification uses a digital elevation model (DEM) and sensor model to remove relief displacement and produce a planimetrically accurate image where every pixel is in its true geographic position.

Question 5

Which remote sensing platform is best suited for rapid disaster response mapping due to its cloud-penetrating capability and day/night operation?

Accepted Answer

Synthetic Aperture Radar (SAR) satellites like Sentinel-1

Answer

SAR systems operate regardless of cloud cover or sunlight, making them ideal for post-disaster mapping when optical imagery is often blocked by storm clouds.

GIS - Geographic Information System Practice Test

GIS - Geographic Information System Practice Test

GIS Remote Sensing and Imagery 5