# Cambridge Housing Map — Analytics Data Dictionary

Join key: `map_lot`. One row per Cambridge parcel.

| Field | Unit | Allowed values | Description |
|-------|------|----------------|-------------|
| `map_lot` |  |  | Cambridge Assessor Map-Lot parcel identifier (join key). |
| `lot_area_sqft` | sqft |  | Lot area, from the Assessor's recorded land area. |
| `zoning_district` |  |  | Base zoning district code (e.g. C-1, BA, Res A-1). |
| `pud_type` |  |  | PUD / special-district type, if the parcel is in one. |
| `max_stories_byright` | stories |  | Maximum stories allowed by-right at market rate. |
| `aho_max_stories` | stories |  | Maximum stories under the Affordable Housing Overlay (approximate). |
| `render_bucket` |  | six, four, corridor, pud, nonres, os, unknown | Map render/zoning bucket. |
| `neighborhood` |  |  | Cambridge neighborhood containing the parcel centroid. |
| `owner` |  |  | Primary owner of record. |
| `co_owner` |  |  | Secondary owner of record, if any. |
| `mailing_address` |  |  | Owner mailing address of record. |
| `land_value` | USD |  | Assessed land value. |
| `building_value` | USD |  | Assessed building value. |
| `assessed_value` | USD |  | Total assessed value. |
| `last_sale_price` | USD |  | Most recent recorded sale price. |
| `last_sale_date` | ISO-8601 date |  | Most recent recorded sale date. |
| `year_built` | year |  | Year the primary structure was built. |
| `building_sqft` | sqft |  | Gross building area. |
| `property_class` |  |  | Assessor property-class description. |
| `residential_units` | units |  | Residential unit count on the parcel, per the assessor. |
| `has_active_project` |  | True, False | Whether a tracked (non-likely-complete) development project exists on this parcel. |
| `project_stage` |  |  | Stage of the tracked project, if any. |
| `proposed_units` | units |  | Proposed unit count of the tracked project, if any. |
| `dev_type` |  |  | Development type of the tracked project, if any. |
| `project_source` |  |  | Provenance of the tracked project, if any. |

## Caveats

- Eligibility shows what the ordinance allows (story limits only) — FAR, setbacks, and lot coverage are NOT applied, so max_stories_byright/aho_max_stories overstate buildable size.
- Zoning is assigned by parcel centroid; parcels at district boundaries may be misclassified.
- aho_max_stories is approximate; the AHO +3 stories / +35 ft exceedance is not fully modeled.
- PUD / special-district parcels (pud_type set) have site-specific entitlements not captured here.
- Ownership/assessing fields are public Assessor records (FY2026) and may lag recent sales.
- has_active_project reflects only projects this site tracks; absence is not proof of no activity. By-right projects under ~50,000 sqft surface only at permitting.
- Not an official City of Cambridge dataset; independent and volunteer-built.