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Extract shorelines, centerlines and channel widths from multi-temporal water body masks. Quantify shoreline migration, channel migration, change hotspots and migration zones. Use when analyzing river channel changes, identifying erosion/deposition areas, or generating river morphology reports.
Extract shorelines, centerlines and channel widths from multi-temporal water body masks. Quantify shoreline migration, channel migration, change hotspots and migration zones. Use when analyzing river channel changes, identifying erosion/deposition areas, or generating river morphology reports.
Extracts shorelines, centerlines, and channel widths from multi-temporal water body masks. Quantifies shoreline migration, channel migration, and change hotspots.
Use when the user wants to:
# Basic analysis with default parameters
python scripts/river_morphology_change.py --output-dir ./rmc-output
# Custom transect spacing and hotspot percentile
python scripts/river_morphology_change.py \
--transect-spacing 30.0 \
--hotspot-percentile 85.0 \
--output-dir ./rmc-output
# With custom water threshold
python scripts/river_morphology_change.py \
--water-threshold 0.1 \
--min-channel-width 15.0 \
--output-dir ./rmc-output
| Parameter | Default | Description |
|---|---|---|
--input-masks | None | Input water mask GeoTIFF files (ordered by time) |
--transect-spacing | 50.0 | Distance between transects in map units |
--min-channel-width | 20.0 | Minimum channel width for quality flagging |
--shoreline-method | threshold | Shoreline extraction method: threshold, canny, manual |
--water-threshold | 0.0 | Water extraction threshold (NDWI/MNDWI) |
--hotspot-percentile | 90.0 | Percentile threshold for hotspot detection |
--output-dir | ./rmc-output | Output directory |
| File | Description |
|---|---|
shorelines.geojson | Shoreline features for each time period |
centerlines.geojson | Centerline features for each time period |
transects.geojson | Perpendicular transect lines along centerline |
migration_rates.csv | Migration distances and rates per transect |
change_hotspots.geojson | Hotspot features where migration exceeds threshold |
request.json | Analysis request metadata |
dataset-manifest.json | Dataset inventory and period information |
output-manifest.json | Output file inventory and statistics |
qa.json | Quality assurance checks |
| Code | Name | Description |
|---|---|---|
| 1 | high | Clean intersection, single shoreline crossing |
| 2 | medium | Small migration or minor complexity |
| 3 | low | Multiple intersections, complex geometry |
| 4 | invalid | No intersection or processing error |
| Code | Name | Description |
|---|---|---|
| -1 | erosion | Shoreline retreats (water expands) |
| 0 | stable | No significant change |
| 1 | deposition | Shoreline advances (water contracts) |
Uses NDWI (Normalized Difference Water Index) or MNDWI (Modified NDWI) to extract water bodies from multispectral imagery:
Uses Voronoi-based medial axis extraction:
Generates perpendicular transects along the centerline at regular intervals. Each transect is perpendicular to the local tangent direction.
Uses perpendicular intersection method:
Identifies transects where migration distance exceeds the specified percentile threshold (default: 90th percentile).
| Code | Meaning |
|---|---|
| 0 | Success |
| 2 | Argument error |
| 3 | Dependency missing |
| 6 | Data validation failure |
| 7 | Processing failure |
本 skill 可自动从 Microsoft Planetary Computer 下载数据 (无需 API key):
python river_morphology_change.py --bbox 116,39,117,40 --date-range 2024-06-01,2024-06-30 --output-dir
--bbox W,S,E,N: WGS-84 边界框 (西, 南, 东, 北)--date-range START,END: 日期范围 (YYYY-MM-DD,YYYY-MM-DD)--aoi-file : 替代 --bbox 的 GeoJSON 多边形--cache-dir : 缓存目录 (默认 ~/.geoskill_cache)当用户只给 --bbox + --date-range (没有 --image) 时，skill 自动下载数据。
当用户给 --image 时，走原文件路径 (向后兼容)。
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