Reproducible ML pipeline for detecting persistent road infrastructure underinvestment in Accra.
Accra Road Surface Mapping Pipeline (Sentinel-2 Only)
Overview
This project provides a fully reproducible workflow for analysing transport infrastructure inequality in Accra, Ghana.
The workflow is divided into three integrated parts:
- Part 1 — Road Surface Mapping (Python)
- Part 2 — Spatial Analysis (QGIS)
- Part 3 — Statistical Analysis (Python → Excel)
Together, these steps identify blind spots in road infrastructure, assess population exposure, and evaluate transport accessibility inequalities.
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PART 1 — ROAD SURFACE MAPPING (PYTHON)
What This Part Does
This pipeline uses Sentinel-2 imagery and OpenStreetMap (OSM) data to:
1. Extract road surface tags from OSM
2. Generate weak training labels (paved vs unpaved)
3. Segment the road network into 100 m segments
4. Extract Sentinel-2 spectral features
5. Train machine learning models using spatial cross-validation
6. Predict road surface classes
7. Detect road surface changes between years
8. Compare model performance
Data Download
drive.google.com
Place files into:
project_root/
├── snapshots/
├── imagery/
├── QGIS-PART 2/
├── Blindspots_final.csv/
├── Non_blind_final.csv/
├── Stable_unpaved_roads_fixed.csv/
├── Blindspots_districts.csv/
How to Run (Part 1)
Step 1 — Install dependencies
install_requirements.bat
Step 2 — Run pipeline
run_pipeline.bat
Output (Part 1)
outputs/
Includes:
- GLOBAL_preprocessing/
- step5_models/
- step6_predictions/
- step7_change_detection/
- _COMPARISON_STEP8/
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PART 2 — QGIS ANALYSIS PACKAGE
Overview
This section provides the full QGIS environment used to:
- Visualise spatial patterns
- Identify blind spots
- Analyse accessibility
- Generate manuscript maps
- Export datasets for statistical analysis
Contents of QGIS folder:
- Accra_QGIS_Project.qgz
- GHSL population raster
- Blind spot polygons
- Stabl …