# Aerial Building Footprint Extractor

A geospatial computer vision pipeline that extracts building footprints from aerial imagery and converts them into vectorised GeoJSON polygons for downstream GIS use.

## Features

* Downloads or loads aerial imagery for a selected area

* Runs zero-shot building segmentation using the Segment Anything Model

* Generates raster masks for detected building regions

* Converts segmented regions into vector polygons

* Calculates per-building geometry and area information

* Exports building footprints as GeoJSON

* Produces interactive visualisations for reviewing extracted footprints

* Supports downstream workflows in QGIS and other GIS platforms

## Tech Stack

* Python

* Segment Anything Model

* SAMGeo

* PyTorch

* Rasterio

* Shapely

* GeoPandas

* NumPy

* GDAL-compatible geospatial processing

* GeoJSON

* HTML visualisation

## Project Structure

* download\_data.py — downloads or prepares aerial imagery

* segment.py — runs SAM-based building segmentation

* vectorize.py — converts raster masks into vector polygons

* visualize.py — creates interactive footprint visualisations

* fix.py — utility script for geometry or output corrections

* requirements.txt — Python dependencies

## Installation

Create and activate a virtual environment, then install the required packages:

pip install -r requirements.txt

## Workflow

1. Download or place aerial imagery inside the local data/ directory.

2. Run the segmentation pipeline:

python segment.py

3. Convert the generated masks into GeoJSON polygons:

python vectorize.py

4. Generate the interactive visualisation:

python visualize.py

## Output

The pipeline can generate:

* Building segmentation masks

* Vectorised building footprint polygons

* GeoJSON files

* Interactive HTML maps

* Per-building area and geometry metadata

## Applications

* Urban planning

* Property and infrastructure analysis

* GIS automation

* Disaster assessment

* Mapping and geospatial intelligence

* Automated building inventory generation

## Notes

The data/ and outputs/ folders are excluded from version control because they may contain large imagery files and generated results.

Model weights and virtual environments are also excluded from this repository.