# Cambridge Housing Map

> Independent, volunteer-built map of Cambridge, MA zoning eligibility and the
> housing development pipeline. Open data for analysis. Not an official city site.

## Data

- [Parcel analytics (JSON)](https://cambridgehousingmap.org/data/analytics.json): one geometry-free row per
  parcel — lot size, zoning, by-right/AHO stories, ownership + assessing, pipeline status.
- [Parcel analytics (CSV)](https://cambridgehousingmap.org/data/analytics.csv): same data for spreadsheets/pandas.
- [Data dictionary](https://cambridgehousingmap.org/data/dictionary.md): field definitions, units, allowed values, caveats.
- [Dataset manifest](https://cambridgehousingmap.org/data/manifest.json): machine-readable catalog of all datasets.
- [Development pipeline](https://cambridgehousingmap.org/data/projects.json): coalesced projects with stage + provenance.
- [Parcels with geometry](https://cambridgehousingmap.org/assets/parcels.json): polygons for mapping/spatial joins.

## Fetching

Use the exact URLs above — paths are case-sensitive and require the file extension.
A wrong or partial path returns HTTP 404 (not the site HTML). CORS is open
(`access-control-allow-origin: *`). `analytics.json` is ~8 MB; if your client caps
response size, use `analytics.csv` or pull `manifest.json` (small) first.

## Example questions (fetch analytics.json, then analyze)

- What is the ratio of parcels under 6,000 sqft to those 6,000 sqft and over? (use `lot_area_sqft`)
- Which owners hold the most parcels or highest total assessed value? (use `owner`, `assessed_value`)
- How many active projects are in each neighborhood? (use `neighborhood`, `has_active_project`)

## Caveats

Eligibility is story-limits-only (no FAR/setbacks); zoning is centroid-assigned; assessing is
public record and may lag sales. See the data dictionary for the full list.