18-Geol-B2 Terrain Analysis · December 2017
Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)
National Exams — December 2017 — 04-Geol-B2 Terrain Analysis. Three-hour, open-book exam; approved Casio/Sharp calculator permitted. The paper prints SIX questions; per the instructions only the first five as they appear in the answer book are marked (100 points total), but all six are answered below so the set stands as a complete study resource.
Reference texts: Lillesand, Kiefer & Chipman, Remote Sensing and Image Interpretation (7th ed.) — primary reference for spectral/spatial/radiometric resolution, radar imaging geometry, Landsat sensor comparisons, and image-interpretation elements (Q1, Q2, Q3, Q5); Sabins, Remote Sensing: Principles and Interpretation (3rd ed.) — radar depression-angle geometry, albedo, atmospheric correction, Landsat 8 TIRS (Q1, Q2, Q5); Mollard, J.D. & Janes, J.R., Airphoto Interpretation and the Canadian Landscape (Energy, Mines and Resources Canada, 1984) — the exam's own required reference for the stereopair interpretation questions (Q4, Q6); Van Zuidam, Terrain Analysis and Classification Using Aerial Photographs — slope-form and karst terrain-classification context (Q1, Q6).
Question text not reproduced: the examination questions are © Engineers and Geoscientists BC. Open the official past paper (linked at the top of this page) to read the question, then follow the worked solution below.
The Multispectral Scanner (MSS), flown on Landsat 1–5, and the Thematic Mapper (TM), flown on Landsat 4–5, image the same broad orbital swath but differ substantially in every resolution dimension, and each difference translates directly into greater practical usefulness for TM.
| Property | MSS | TM |
|---|---|---|
| Spatial resolution | 79 m × 79 m (visible/NIR) | 30 m × 30 m (visible/NIR/SWIR); 120 m thermal |
| Spectral bands | 4 bands: green, red, two NIR | 7 bands: blue, green, red, NIR, two SWIR, one TIR |
| Radiometric resolution | 6-bit (64 grey levels) | 8-bit (256 grey levels) |
Spatial resolution. TM's 30 m pixel resolves roughly seven times more ground area per pixel than MSS's 79 m pixel (a linear factor of ≈2.6, so an area factor of ≈6.9), letting TM delineate smaller land parcels, narrower drainage features, and finer land-cover boundaries that MSS blends into mixed pixels.
Spectral resolution. TM adds a blue band (enabling true-colour composites and water-column penetration/bathymetric work MSS cannot do), and critically adds two shortwave-infrared bands (TM5 ≈1.55–1.75 μm and TM7 ≈2.08–2.35 μm) that are diagnostic of mineral/clay mineralogy (hydroxyl and carbonate absorption features), vegetation and soil moisture content, and burn severity — none of which MSS's four bands, confined to the visible/near-infrared, can distinguish. TM's added thermal band (TM6, 120 m) supports land-surface-temperature applications entirely absent from MSS.
Radiometric resolution. TM's 8-bit (256-level) quantization resolves four times finer radiance increments than MSS's 6-bit (64-level) quantization, letting TM detect subtler reflectance differences within a cover type (e.g. crop stress, subtle moisture gradients) that would be lost in MSS's coarser digital-number steps.
Together, finer spatial detail, a broader and more diagnostic set of spectral bands (especially the SWIR pair and the thermal band), and finer radiometric quantization make TM data useful for a substantially wider range of geological, agricultural, hydrological, and environmental applications than MSS, at the cost of a larger, more complex dataset.
