Satellite Detected Surface Waters Evolution in Southern Provinces of Kien Giang, Dong Thap & An Giang, Vietnam

Name: Satellite Detected Surface Waters Evolution in Southern Provinces of Kien Giang, Dong Thap & An Giang, Vietnam
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

This map illustrates the satellite-detected surface waters extent in the southern provinces of kien Giang, An Giang, Dong Thap & Can tho as observed from the Sentinel-1 SAR images acquired on 16 & 28 August 2018. In the analysed area, an increase of surface waters is observed mainly in agricultural and paddy fields areas. It is likely that flood waters have been systematically underestimated along highly vegetated areas along main river banks and within built-up urban areas because of the special characteristics of the satellite data used. This is a preliminary analysis and has not yet been validated in the field. Please send ground feedback to UNITAR - UNOSAT.

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 Surface Waters & Evolution in Long An Province, Vietnam

This map illustrates the satellite-detected surface waters extent in Long An province and in the southern part of Cambodia, as observed from the Sentinel-1 SAR images acquired on 16 & 28 August 2018. In the analysed area, an increase of surface waters is observed mainly in agricultural and paddy fields areas. In addition, using WorldPop data, we can estimate that ~200,000 people are living within or close to flooded zones in the province of Long An. It is likely that flood waters have been systematically underestimated along highly vegetated areas along main river banks and within built-up urban areas because of the special characteristics of the satellite data used. This is a preliminary analysis and has not yet been validated in the field. Please send ground feedback to UNITAR - UNOSAT.