UNOSAT Live Web map- Cyclone Ditwah and Floods in Sri Lanka (November 2025)

Name: UNOSAT Live Web map- Cyclone Ditwah and Floods in Sri Lanka (November 2025)
Creator: United Nations Satellite Centre (UNOSAT)
License: http://www.opendefinition.org/licenses/cc-by-sa

✦ DISCOVERED BY ORIONAIUnited Nations Satellite Centre (UNOSAT)EnvironmentSri Lanka

Sri Lanka

About this dataset

**UNOSAT code: FL20251128LKA, GDACS ID: 1001238** This application provides geospatial information from ongoing satellite-based assessments of the floods in Sri Lanka triggered by Cyclone DITWAH in November 2025. Important note: Flood analysis derived from radar imagery may underestimate the presence of standing water in built-up and densely vegetated areas due to the backscattering properties of the radar signal.

Documentation

UNOSAT datasets and maps are produced using a variety of methods. In general, analysts closely review satellite imagery, often comparing two or more images together, and determine notable changes between the images. For damage assessments, refugee or IDP assessments, and similar analyses, these changes are then manually documented in the vector data by the analyst. For flood extractions, landcover mapping and similar analyses, a variety of automated remote sensing techniques are used to extract the relevant information which is then reviewed and revised as necessary by the analyst. In all cases, resulting data is then loaded into a standardized UNOSAT geodatabase and exported asshapefiles for dissemination. This is a preliminary assessment and has not yet been validated in the field. It is important to consider the characteristics of the source imagery used in the analyses when interpreting results. For damage assessments it should be noted that only significant damage to the structural integrity of the buildings analyzed can be seen in imagery, while minor damage such as cracks or holes may not be visible at all. For flood extractions using radar data it is important to note that urban areas and highly vegetated areas may mask the flood signature and result in underestimation of flood waters. Users with specific questions or concerns should contact unosat@unitar.org to seek clarification.

Related datasets

✦ Suggested by OrionAI

UNOSAT Live Web map - Floods in Sri Lanka

**UNOSAT code: FL20240603LKA, GDACS ID: 1102660** This application provides geospatial information regarding the floods in Sri Lanka in June 2024. Important note: The boundaries and names shown, and the designations used on this map do not imply official endorsement or acceptance by the United Nations. The United Nations Satellite Centre. UNOSAT is not responsible for the misuse or misrepresentation of the map.