Satellite detected water extents in Red River Delta, Viet Nam as of 13 September 2024

Name: Satellite detected water extents in Red River Delta, Viet Nam as of 13 September 2024
Creator: United Nations Satellite Centre (UNOSAT)
License: http://www.opendefinition.org/licenses/cc-by-sa

✦ DISCOVERED BY ORIONAIUnited Nations Satellite Centre (UNOSAT)WaterViet Nam

Viet Nam

About this dataset

**UNOSAT code: TC20240905VNM, GDACS ID: 1001090** This map illustrates the aggregated floods using Sentinel-1 images acquired on 13 September 2024 at 05:58 local time. Within the analysed area of about 38,000 km², a total of about 1,300 km² of land appears to be affected by flood waters. Based on Worldpop spatial demographic data, about 900,000 people are exposed or living close to flooded areas. This is a preliminary analysis and has not yet been validated in the field. Please send ground feedback to the United Nations Satellite Centre (UNOSAT). Important note: Flood analysis from radar images may underestimate the presence of standing waters in built-up areas 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.

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Satellite detected water extents in Red River Delta, Viet Nam as of 25 September 2024

**UNOSAT code: TC20240905VNM, GDACS ID: 1001090** Satellite detected water extents in Red River Delta, Viet Nam as of 25 September 2024 This map illustrates the floods using Sentinel-1 images acquired on 25 September 2024 at 05:58 local time. Within the analysed area of about 38,000 km², a total of about 600 km² of land appears to be affected by flood waters. Flood extent appears to have decreased by about 700 km² since 13 September 2024. Based on Worldpop spatial demographic data, about 400,000 people are exposed or living close to flooded areas as of 25 September 2024. This is a preliminary analysis and has not yet been validated in the field. Please send ground feedback to the United Nations Satellite Centre (UNOSAT). Important note: Flood analysis from radar images may underestimate the presence of standing waters in built-up areas and densely vegetated areas due to the backscattering properties of the radar signal.