NoVA Building Permit Atlas: The Single-Family to Multifamily Shift, 2000-2025 (Keystone GIS Day 93)

Twenty-six years of Census Bureau building-permit records for the nine Northern Virginia jurisdictions, split by structure type. Single-family permits fell from 70% of authorized units in 2000-2005 to 40% in 2021-2025, while 5+ unit buildings now carry most new housing. Includes a county-by-year GeoPackage, an IsolationForest anomaly layer, and a time-animated map.Produced by the Keystone GIS Northern Virginia Autonomous GIS Research Program. Full methodology, interactive map, and FGDC metadata: https://keystonegis.com/datasets/nova-building-permits-day93.html