B.S.F. or B.Sc.F. Bachelor of Science in Forestry Bachelor of Science in Forestry: Remote Sensing and GIS in Forestry 2 — Questions and Answers
Question 1: A forester wants to identify all areas within 500 meters of a stream network to define riparian buffer zones in a GIS. Which spatial analysis function should be used?
- Overlay
- Buffer (Correct answer)
- Clip
- Dissolve
Correct answer: Buffer
A Buffer operation creates a zone of specified distance around a feature (such as a stream), which is the standard GIS method for delineating riparian protection areas.
Question 2: What is 'ground-truthing' in the context of forest remote sensing?
- Downloading satellite data to a ground server
- Verifying classified map results with field observations (Correct answer)
- Calibrating satellite sensors from a ground station
- Computing elevation values from stereo imagery
Correct answer: Verifying classified map results with field observations
Ground-truthing involves visiting sample locations in the field to compare observed conditions with remote sensing classifications, enabling accuracy assessment of the resulting maps.
Question 3: Which unsupervised image classification method groups pixels into clusters based on spectral similarity without requiring prior training samples?
- Maximum Likelihood Classification
- K-means clustering (Correct answer)
- Support Vector Machine
- Random Forest classification
Correct answer: K-means clustering
K-means clustering is an unsupervised algorithm that iteratively groups pixels into a predefined number of spectrally similar clusters without requiring analyst-provided training data.
Question 4: A Digital Elevation Model (DEM) is used in forestry GIS primarily for which purpose?
- Identifying individual tree species from their reflectance
- Mapping soil nutrient concentrations
- Deriving terrain attributes such as slope, aspect, and watershed boundaries (Correct answer)
- Estimating stand age from spectral signatures
Correct answer: Deriving terrain attributes such as slope, aspect, and watershed boundaries
A DEM represents bare-earth elevation and allows foresters to derive slope, aspect, curvature, and watershed boundaries that are critical for hydrology, site classification, and harvest planning.
Question 5: Which spectral index is specifically designed to detect and map burned forest areas following a wildfire?
- NDVI (Normalized Difference Vegetation Index)
- NBR (Normalized Burn Ratio) (Correct answer)
- EVI (Enhanced Vegetation Index)
- NDWI (Normalized Difference Water Index)
Correct answer: NBR (Normalized Burn Ratio)
NBR (Normalized Burn Ratio) uses near-infrared and shortwave infrared bands to highlight burned forest areas and assess burn severity, and is the standard index for post-fire mapping.
Question 6: Forest fragmentation analysis in GIS commonly relies on which type of landscape metrics to quantify patch size, shape, and connectivity?
- FRAGSTATS metrics (Correct answer)
- LIDAR waveform metrics
- Radiometric calibration factors
- Topographic wetness indices
Correct answer: FRAGSTATS metrics
FRAGSTATS is the standard software for computing landscape pattern metrics (patch area, perimeter, shape index, connectivity) used in forest fragmentation and habitat analysis.
Question 7: What primary advantage does multispectral satellite imagery offer over traditional black-and-white aerial photography for forest mapping?
- Higher spatial resolution
- Lower data acquisition cost per scene
- Ability to distinguish vegetation types based on spectral reflectance differences (Correct answer)
- Longer historical archive availability
Correct answer: Ability to distinguish vegetation types based on spectral reflectance differences
Multispectral imagery captures data across multiple wavelength bands, enabling differentiation of vegetation types by their unique spectral signatures, which is not possible with single-band panchromatic photography.
B.S.F. or B.Sc.F. Bachelor of Science in Forestry Bachelor of Science in Forestry: Remote Sensing and GIS in Forestry 2
A forester wants to identify all areas within 500 meters of a stream network to define riparian buffer zones in a GIS.
Which spatial analysis function should be used?