---

name: flood-extent-mapping description: Extract flood extent from SAR backscatter imagery. Use when the user wants to analyze changes, detect hazards, or generate assessment reports.

Flood Extent Mapping

Extract flood extent from SAR backscatter imagery.

CLI Usage

# Local file mode (backward compatible)
python scripts/flood_extent_mapping.py --sar sar.tif
python scripts/flood_extent_mapping.py --sar sar.tif --threshold -16
python scripts/flood_extent_mapping.py --sar sar.tif --output-dir my_output

# Auto-download mode — fetch Sentinel-1 GRD from Microsoft Planetary Computer
# (no API key required; one scene per invocation)
python scripts/flood_extent_mapping.py \
    --bbox 116,39,117,40 \
    --date-range 2024-06-01,2024-06-30 \
    --output-dir my_output

Data Download

When --bbox (or --aoi-file) and --date-range are provided, the skill auto-downloads one Sentinel-1 GRD scene from the Microsoft Planetary Computer STAC catalog (collection sentinel-1-grd). The downloaded file is written to <output_dir>/downloaded/ and the SAR analysis runs on it exactly as if a local file had been passed via --sar.

The output-manifest.json records data_source, collection, bbox, date_range, and fetched_at whenever auto-download is used.

Parameters

Argument	Required	Default	Description
--sar	One-of	—	Path to local SAR backscatter raster (dB, calibrated)
--bbox	One-of	—	W,S,E,N in WGS-84; triggers auto-download
--date-range	w/ bbox	—	START,END ISO-8601; triggers auto-download
--aoi-file	No	—	GeoJSON Polygon / MultiPolygon (alternative to --bbox)
--threshold	No	-15	Water threshold in dB
--output-dir, -o	No	flood-output	Directory to write outputs
--synthetic	No	off	Use synthetic demo data (no real inputs)

Output

File	Description
flood-report.json	Machine-readable flood extent stats (water area, depth proxy)
report.html	Human-readable HTML report
output-manifest.json	Run metadata + result summary

Exit Codes

Code	Meaning
0	Success
2	Argument error
7	Processing failure