GIS Remote Sensing and Imagery 3

Question 1

What is the primary advantage of hyperspectral imagery over multispectral imagery?

Accepted Answer

Hundreds of narrow contiguous spectral bands enabling material identification

Answer

Hyperspectral sensors capture hundreds of narrow bands, creating a detailed spectral signature that can identify specific minerals, vegetation species, or materials.

Question 2

Which phenomenon explains why satellite images acquired in the morning vs. afternoon may show different shadowing patterns?

Accepted Answer

Solar zenith angle change throughout the day

Answer

The solar zenith angle changes throughout the day, altering shadow length and direction, which affects the appearance of terrain and objects in imagery.

Question 3

What does 'ground truth' mean in the context of remote sensing accuracy assessment?

Accepted Answer

Field-collected reference data used to verify classification results

Answer

Ground truth refers to field-verified observations of actual land cover used to train classifiers and validate classification accuracy.

Question 4

In a confusion matrix for land cover classification, what does the 'overall accuracy' metric represent?

Accepted Answer

The percentage of pixels correctly classified across all classes

Answer

Overall accuracy is the total number of correctly classified pixels divided by the total number of pixels evaluated, expressed as a percentage.

Question 5

Which remote sensing technique is used to measure surface deformation caused by earthquakes or volcanic activity?

Accepted Answer

InSAR (Interferometric SAR)

Answer

InSAR compares phase differences between two SAR acquisitions to detect millimeter-scale ground deformation over large areas.

GIS - Geographic Information System Practice Test

GIS - Geographic Information System Practice Test

GIS Remote Sensing and Imagery 3