Thailand flood history map

Flood events covered

Methodology

Flood extents are derived from satellite radar (SAR) imagery captured during specific flood events, analysed by the source organisations listed below. A location is marked "flooded" when it falls inside a mapped flood polygon for at least one event, "not flooded" when it falls inside an event's analysed area but outside any flood polygon, and "no data" when no covered event's analysed area reaches it at all.

Ground elevation comes from DeltaDTM v1.1 (Deltares and TU Delft, CC BY 4.0), a 30 m bare-earth terrain model: it corrects the Copernicus DEM with ICESat-2 and GEDI satellite lidar and removes buildings and trees, so the height is the ground, not the rooftops. Heights are in metres above mean sea level (the EGM2008 geoid), and we report the median of the 3×3 cells (about 90 m) around the point. We checked it ourselves against 154,765 NASA ICESat-2 ground measurements taken in 2024–2026, after the dataset was made, across Bangkok and the surrounding provinces: the mean absolute error is 0.42 m, the RMSE is 0.76 m and the overall bias is −0.07 m. In built-up areas it is less accurate (RMSE 1.1 m) and reads on average about 0.3 m lower than the satellite measurements. It covers Bangkok and the surrounding central plain only (99.9–101.1° E, 13.3–14.9° N).

See the attribution page