Essay — Advantages and disadvantages of moderate-resolution sensors (10 – 250 m).

Examples: Landsat OLI (30 m), Sentinel-2 MSI (10 – 60 m), MODIS (250 – 1000 m).

Advantages

• Large swath (Landsat ~185 km, Sentinel-2 290 km) — regional/global coverage.
• Frequent revisit combined across constellations (Landsat + Sentinel-2 ≈ every 2–3 days).
• Long archives (Landsat → 1972) for time-series and change detection.
• Free data (USGS, ESA Copernicus).
• Multispectral breadth — enough bands for NDVI, EVI, NBR, water indices.

Disadvantages

• Can’t resolve individual objects — buildings, small fields, trees.
• Mixed pixels at class boundaries hurt classification accuracy.
• Cloud contamination — 16-day repeat means many scenes are unusable.
• Thermal resolution is coarser still (Landsat TIRS 100 m → resampled to 30 m).