PhilSA training deck walking LGUs through building flood impact maps in QGIS. It distinguishes an impact map (which shows consequences on people and land) from a simple flood extent map, then demonstrates the workflow: downloading flood extent and population data from HDX, intersecting the two layers (with a fix-geometry step for errors), and running basic statistics to estimate ~99,182 people potentially affected by Typhoon Basyang and the Shear Line. It closes with PhilSA's rice flood mapping method, which uses the raster calculator expression "(rice × 10) + flood" to classify flooded rice, flooded non-rice, and rice-only areas.
Teacher: Reymar Diwa