# The Waiting Lots

An open, reproducible study of Philadelphia's vacant and parking land, the property tax, and what a revenue-neutral land value (split-rate) tax would change. Prepared as a pilot by the AIA Philadelphia Housing Committee, October 2026, for peer review.

- **Read the study:** `site/index.html` (the published interactive page)
- **Read the method:** [METHODS.md](METHODS.md)
- **Rerun everything:** see "Reproduce" below

## What is here

| Path | Contents |
|---|---|
| `queries/` | The exact SQL and download URLs for the City's property records |
| `data/raw/` | The two CSVs as downloaded on 2026-10-28 |
| `data/derived/` | Parcels with districts and split-rate taxes, district summaries, citywide rates, sensitivity runs |
| `geo/` | Approximate council districts rebuilt from election divisions |
| `src/model.js` | The pro forma and tax model used on the page |
| `src/build_districts.py`, `src/assign_lots.py`, `src/sensitivity.js` | The pipeline |
| `tests/test_model.js` | Checks on the model's math |
| `site/index.html` | The published page |

## Reproduce

Requirements: Python 3.10+ (`pip install shapely pyproj pyshp`) and Node.js 18+.

```
git clone --depth 1 https://github.com/azavea/geo-data vendor/geo-data
python3 src/build_districts.py
python3 src/assign_lots.py
node src/sensitivity.js
node tests/test_model.js
```

## How to review

Open an issue for any error, questionable assumption or better source. The most useful reviews:

1. Land values: do OPA's land assessments for vacant and parking parcels track arm's-length sales?
2. Construction costs, rents and cap rates for a six-story mixed-use building in each district.
3. District assignment near boundaries, against the City's official council district layer.
4. The capitalization assumption (section 7.3 of METHODS.md).

Placeholders are marked as such in METHODS.md section 6.

## Licenses

- Code (`src/`, `tests/`): MIT License (see LICENSE).
- Text and derived tables: Creative Commons Attribution 4.0 (CC BY 4.0).
- City of Philadelphia property data: published by the City through OpenDataPhilly under its own terms.
- Neighborhood and division boundaries: Abaca Labs, CC BY 4.0, via Azavea's geo-data repository.

## Cite

AIA Philadelphia Housing Committee (2026). *The Waiting Lots: land, tax and time in Philadelphia.* Pilot study and open data package, draft for peer review.