{
"name":"DISASTERS_202512_FLOOD_WA/2512_sentinel1_FloodDetection",
"title":"DISASTERS_202512_FLOOD_WA/2512_sentinel1_FloodDetection",
"type":"Map Service",
"typeKeywords":["ArcGIS Server","Service","Map Service"],
"description":"<div style='text-align:Left;'><p style='margin:0 0 11 0;'><b>Dates of Images:<\/b><\/p><p style='margin:0 0 11 0;'><i>Post-Event: <\/i>Dec 10, 2025<span><span><\/span><\/span><\/p><p style='margin:0 0 11 0;'><span><span><i>Pre-Event:<\/i> Dec 7, 2025<\/span><\/span><\/p><p><span style='font-weight:bold;'>Date of Next Image:<\/span><\/p><p style='margin:0 0 11 0;'><span><span>Dec 11, 2025<\/span><\/span><\/p><p><span style='font-weight:bold;'>Summary:<\/span><\/p><p><span>We developed a rapid-response workflow to map flooded areas during this emergency event using multi-temporal Sentinel-1 SAR data. Sentinel-1\u2019s 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.<\/span><\/p><p><span>To highlight flood-induced surface changes, we computed the differenced co-polarized VV backscatter (dVV = VV_post \u2013 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.<\/span><\/p><p><span style='font-weight:bold;'>Suggested Use:<\/span><\/p><p><span>The final output is a binary raster product, where pixels with a value of 1 represent flooded areas (dark blue color).<\/span><\/p><p><span>A permanent water body layer and a binary layer incorporating land cover are also included.<\/span><\/p><p><span style='font-weight:bold;'>Satellite/Sensor:<\/span><\/p><p><span>Sentinel-1 /Synthetic Aperture Radar (SAR)<\/span><\/p><p><span><b>Resolution:<\/b><\/span><\/p><p><span>10 meters<\/span><\/p><p><span><b>Credits:<\/b><\/span><\/p><p><span>Dr. Khuong H. Tran (Khuong.tran@nasa.gov)<\/span><\/p><p><span><b>Esri REST Endpoint:<\/b><\/span><\/p><p><span>See URL section on right side of page<\/span><\/p><p><span><b>WMS Endpoint:<\/b><\/span><\/p><p><a href='https://gis.earthdata.nasa.gov/gis05/services/DISASTERS_202512_FLOOD_WA/sentinel1_FloodDetection/MapServer/WMSServer' target='_blank'>https://gis.earthdata.nasa.gov/gis05/services/DISASTERS_202512_FLOOD_WA/sentinel1_FloodDetection/MapServer/WMSServer<\/a><\/p><\/div>",
"extent":[[-123.10439770082777,-121.687066175511],[46.56267326349595,47.982842289363916]],

"url":"https://gis.earthdata.nasa.gov/gis05/rest/services/DISASTERS_202512_FLOOD_WA/2512_sentinel1_FloodDetection/MapServer"
}