| snippet:
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Flood Detection using Sentinel-1 Synthetic Aperture Radar for the Flooding in Texas July 2025. |
| summary:
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Flood Detection using Sentinel-1 Synthetic Aperture Radar for the Flooding in Texas July 2025. |
| extent:
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[[-99.7576428068876,29.7813974567724],[-98.9177180162359,30.2907422228682]] |
| accessInformation:
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Dr. Khuong H. Tran (Khuong.tran@nasa.gov) |
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thumbnail/thumbnail.png |
| maxScale:
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1.7976931348623157E308 |
| typeKeywords:
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["Data","Service","Map Service","ArcGIS Server"] |
| description:
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<div style='text-align:Left;'><p><span style='font-weight:bold;'>Date of Images:</span></p><p><span>Post-Event: Jul 11, 2025 at 00:35 UTC (July 10, 2025, 7:35:12 PM CDT)</span></p><p><span>Pre-Event: Jun 05, 2025 </span></p><p><span style='font-weight:bold;'>Date of Next Image:</span></p><p><span>July 2, 2025</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’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.</span></p><p><span>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.</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 style='font-weight:bold;'>Satellite/Sensor:</span></p><p><span>Sentinel-1 /Synthetic Aperture Radar (SAR)</span></p><p><span style='font-weight:bold;'>Resolution:</span></p><p><span>10 meters</span></p><p><span style='font-weight:bold;'>Credits:</span></p><p><span>Dr. Khuong H. Tran (Khuong.tran@nasa.gov)</span></p><p><span style='font-weight:bold;'>Esri REST Endpoint:</span></p><p><span>See URL section on right side of page</span></p><p><span style='font-weight:bold;'>WMS Endpoint:</span></p><p><a href='https://maps.disasters.nasa.gov/ags03/services/texas_flood_202507/s1_flooddetection/MapServer/WMSServer' rel='nofollow ugc' target='_blank'>https://maps.disasters.nasa.gov/ags03/services/texas_flood_202507/s1_flooddetection/MapServer/WMSServer</a></p></div> |
| licenseInfo:
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<DIV STYLE="text-align:Left;"><DIV><DIV><P><SPAN>The threshold-based approach may lack robustness when delineating flooded areas due to noisy Sentinel-1 backscatter signals and terrain-induced effects.</SPAN></P><P><SPAN>NASA data and products are freely available to federal, state, public, non-profit and commercial users. This information can be experimental- or research-grade data products and may not be appropriate for operational use. These NASA data products, services, and the Disasters Mapping Portal are intended to aid decision makers and enhance situational awareness, but these data are not guaranteed to be consistently available or routinely updated. Use of this product should include: "Contains modified Copernicus Sentinel data (2025) processed by ESA".</SPAN></P></DIV></DIV></DIV> |
| catalogPath:
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|
| title:
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Flood Detection using Sentinel-1 Synthetic Aperture Radar for the Flooding in Texas July 2025 |
| type:
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Map Service |
| url:
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|
| tags:
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["Sentinel-1","USA","New Mexico","NASA","NASA Disasters Program","ESA","SAR","Synthetic Aperture Radar","Copernicus","Texas","Kerrville"] |
| culture:
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en-US |
| name:
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s1_flooddetection |
| guid:
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C41E06A8-907F-4B51-A810-8E1FEFF3E1DF |
| minScale:
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0 |
| spatialReference:
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GCS_WGS_1984 |