Session 3 covers Sentinel-2 bands, band combinations, and spectral indices. It introduces the 13 spectral bands of the Sentinel-2 Multispectral Imager (MSI), ranging from 10m to 60m resolution, and explains how individual bands capture different features of the Earth's surface across blue, green, red, near-infrared, and short-wave infrared wavelengths. The session then explains how stacking three bands into RGB composites produces different visualisations — including true colour (4-3-2), false colour infrared (8-4-3), short-wave infrared (12-8A-4), agriculture (11-8-2), geology (12-11-2), and bathymetric (4-3-1) — each designed to highlight specific land cover features. Hands-on exercises guide participants through creating true and false colour composites in QGIS using the Build Virtual Raster tool, accessing Sentinel-2 data via the CopPhil Infrastructure portal, and computing spectral indices such as NDVI, EVI, NDWI, NBR, NDBI, and mangrove indices using the Raster Calculator, culminating in producing and exporting a formatted NDVI map with legend, title, and scale bar using QGIS Print Layout.
Teacher: Alvin Baloloy