aparna362/sentinel2-change-analysis

Sentinel-2 change detection pipeline for an open-pit mining site in Zambia. Detects land-surface change between two acquisitions (Aug–Sep 2023) using Change Vector Analysis with a robust median/MAD threshold. Outputs change polygons stored in a SQLite/GeoPackage database with interactive map visualisation. # Sentinel-2 Change Analysis — Open-Pit Mine, Zambia A geospatial pipeline that detects land-surface change between two Sentinel-2 acquisitions (**2023-08-12** → **2023-09-02**) over an open-pit mining site in Zambia. It stores results in a spatial database and produces static and interactive figures. | Part | Stage | Module | Output | |------|-------|--------|--------| | 1 | Data preparation | `src/data_preparation.py` | `data/processed/sentinel2_*_stack.tif` | | 2 | Change detection | `src/change_detection.py` | `change_map.tif`, `change_binary.tif` | | 3 | Feature extraction + storage | `src/feature_extraction.py` | `changes.gpkg` (SQLite/GeoPackage) | | 4 | Visualisation | `src/visualize.py` | `outputs/change_overview.png`, `change_map.html` | | 5 | Analysis & interpretation | `report.md` | — | Three extra scripts show **why CVA was chosen** over other threshold methods: | Script | What it shows | Output | |--------|--------------|--------| | `src/otsu_threshold.py` | Otsu flags 45.75% — fails on unimodal histogram | `outputs/otsu_threshold.png` | | `src/mean_std_threshold.py` | Mean/std shifts when outliers change | `outputs/mean_std_threshold.png` | | `src/threshold_comparison.py` | All three methods on one figure | `outputs/threshold_comparison.png` | Full engineering reference: DOCUMENTATION.md --- ## How to run ```bash # 1. Create environment and install dependencies python3 -m venv .venv source .venv/bin/activate # Windows: .venv\Scripts\activate pip install -r requirements.txt # 2. Run the full pipeline (Parts 1–4) python src/pipeline.py # 3. Run the threshold comparison scripts (optional) python src/otsu_threshold.py python src/mean_std_threshold.py python src/threshold_comparison.py ``` Note: the threshold scripts need the stacks from Part 1. If you skip the full pipeline, run `python src/data_preparation.py` first. Each stage can also be run on its own. All paths and parameters are in `src/config.py`. ### Inputs expected ``` inpu …