---

name: urban-expansion-monitor description: > Detect and quantify urban expansion from multi-temporal built-up rasters. Use when the user wants to analyze changes, compare multi-temporal rasters, compute indices, or generate assessment reports.

Urban Expansion Monitor

Detect and quantify urban expansion from multi-temporal built-up rasters.

CLI Usage

python scripts/urban_expansion_monitor.py --before before.tif --after after.tif
python scripts/urban_expansion_monitor.py --before before.tif --after after.tif --threshold 0.6
python scripts/urban_expansion_monitor.py --before before.tif --after after.tif --output-dir my_output

Data Download

This skill can auto-fetch a pair of Landsat Collection 2 Level-2 scenes from the Microsoft Planetary Computer when given a bounding box + date range. The --date-range is split at the midpoint: the first half is used for --before and the second half for --after.

python scripts/urban_expansion_monitor.py \
  --bbox 116,39,117,40 \
  --date-range 2020-01-01,2024-12-31 \
  --output-dir ./expansion-output

The PYTHONPATH must include the parent of _geoskill_data_fetcher/ (the same directory the 50 skills live in). Set it once:

export PYTHONPATH="/path/to/行业Skill创意-20260727"

Parameters

Argument	Required	Default	Description
--before	Yes	—	Path to "before" built-up raster (continuous built-up index or binary mask)
--after	Yes	—	Path to "after" built-up raster (same grid as --before)
--threshold	No	0.5	Built-up classification threshold (values ≥ threshold are considered urban)
--output-dir, -o	No	expansion-output	Directory to write outputs

Output

File	Description
expansion-report.json	Machine-readable expansion stats (areas, growth rate)
report.html	Human-readable HTML report
output-manifest.json	Run metadata + result summary

Exit Codes

Code	Meaning
0	Success
2	Argument error (e.g. missing input file)
7	Processing failure