DISASTERS_202607_FLOOD_TX/202616_sentinel1

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Service Description: <div style='text-align:Left;'><div><div>Post-Event: May 1 to July 1, 2026Pre-Event: July 18, 2026Date of Next Image:Dec 11, 2025Summary:We developed a rapid-response workflow to map flooded areas during this emergency event using multi-temporal Sentinel-1 SAR data. Sentinel-1’s SAR backscatter characteristics are particularly effective for detecting surface water: water surfaces typically exhibit low backscatter, whereas non-water areas show higher backscatter. Leveraging this physical property, we distinguished between water and non-water surfaces from both pre- and post-flood observations.To highlight flood-induced surface changes, we computed the differenced co-polarized VV backscatter (dVV = VV_post – VV_pre). This change detection technique enhances the visibility of newly inundated areas. We then applied a simple threshold to the dVV image to separate flooded from non-flooded areas.Suggested Use:The final output is a binary raster product, where pixels with a value of 1 represent flooded areas (dark blue color).A permanent water body layer and a binary layer incorporating land cover are also included.Satellite/Sensor:Sentinel-1 /Synthetic Aperture Radar (SAR)Resolution:10 metersCredits:Dr. Khuong H. Tran (Khuong.tran@nasa.gov)Esri REST Endpoint:See URL section on right side of pageWMS Endpoint:https://maps.disasters.nasa.gov/ags03/services/NM_FIre_202506/sentinel1_flood/MapServer/WMSServe</div></div></div>

Map Name: sentinel1_FloodDetection

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Description: Post-Event: May 1 to July 1, 2026Pre-Event: July 18, 2026Date of Next Image:Dec 11, 2025Summary:We developed a rapid-response workflow to map flooded areas during this emergency event using multi-temporal Sentinel-1 SAR data. Sentinel-1’s SAR backscatter characteristics are particularly effective for detecting surface water: water surfaces typically exhibit low backscatter, whereas non-water areas show higher backscatter. Leveraging this physical property, we distinguished between water and non-water surfaces from both pre- and post-flood observations.To highlight flood-induced surface changes, we computed the differenced co-polarized VV backscatter (dVV = VV_post – VV_pre). This change detection technique enhances the visibility of newly inundated areas. We then applied a simple threshold to the dVV image to separate flooded from non-flooded areas.Suggested Use:The final output is a binary raster product, where pixels with a value of 1 represent flooded areas (dark blue color).A permanent water body layer and a binary layer incorporating land cover are also included.Satellite/Sensor:Sentinel-1 /Synthetic Aperture Radar (SAR)Resolution:10 metersCredits:Dr. Khuong H. Tran (Khuong.tran@nasa.gov)Esri REST Endpoint:See URL section on right side of pageWMS Endpoint:https://maps.disasters.nasa.gov/ags03/services/NM_FIre_202506/sentinel1_flood/MapServer/WMSServe

Service Item Id: 743afbe565bf4e5c80c99ec65aa5681d

Copyright Text: Dr. Khuong H. Tran (Khuong.tran@nasa.gov)

Spatial Reference: 4326 (4326) LatestVCSWkid(0)

Single Fused Map Cache: false

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Units: esriDecimalDegrees

Supported Image Format Types: PNG32,PNG24,PNG,JPG,DIB,TIFF,EMF,PS,PDF,GIF,SVG,SVGZ,BMP

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Supports Dynamic Layers: true

MaxRecordCount: 2000

MaxSelectionCount: 2000

MaxImageHeight: 4096

MaxImageWidth: 4096

Supported Query Formats: JSON, geoJSON, PBF

Supports Query Data Elements: true

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Supports Datum Transformation: true

Child Resources: Info Dynamic Layer

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DISASTERS_202607_FLOOD_TX/202616_sentinel1_FloodDetection (MapServer)