Data sources
Plattow queries the same public services the federal agencies publish themselves. Every overlay and every report card is sourced from a U.S. government endpoint listed below.
| What | Source | Vintage |
|---|---|---|
| Address geocoding | U.S. Census Geocoder | Current (Public AR) |
| USDA loan eligibility | USDA Rural Development Eligibility | Current |
| FEMA flood zones (NFHL) | FEMA National Flood Hazard Layer | Rolling updates |
| FEMA natural hazard risk | FEMA National Risk Index (NRI) | 2023 vintage |
| FEMA LOMR, LOMA, BFE | NFHL (layers 1, 16, 34) | Rolling updates |
| Elevation | USGS Elevation Point Query Service | Current (3DEP) |
| Wildfire hazard | USFS Wildfire Hazard Potential | 2023 |
| Superfund sites | EPA EMEF EF Points | Rolling updates |
| Coastal Barrier Resources System | USFWS / USGS CBRS | Current |
| Transportation noise (aviation / road / rail) | BTS National Transportation Noise Map | 2020 vintage |
| Public lands (BLM, USFS, NPS) | BLM National Surface Management Agency | Rolling updates |
| Military installations | National Transportation Atlas (DoD) | Rolling updates |
| Property lot lines | Regrid nationwide parcels | Rolling updates |
| Map base tiles | OpenStreetMap contributors | Rolling updates |
What "vintage" means
"Current" means the source is the agency's live service and reflects whatever the agency considers current. "Rolling updates" means the data updates regularly without a fixed annual cadence. A year vintage (e.g., "2023") means the source last released a major update in that year — useful to know for slow-changing datasets like wildfire hazard maps that aren't refreshed daily.
How accurate is this?
Every report is only as accurate as its source. FEMA flood zones can be revised by Letters of Map Revision (LOMR) or Amendment (LOMA), and the NRI is calculated at census-tract granularity — two houses on the same block share the same score. USDA eligibility polygons follow rural-area definitions that can change. Treat Plattow as the first look, not the final word.