1. Search to a point
Complete addresses are submitted to the U.S. Census Geocoder and normalized. ZIP codes, states, counties, cities, and Census-designated places are resolved through Census TIGERweb to an approximate center. Every result appears on a draggable map before analysis. Search text is not placed in public URLs or written to the soil cache.
2. Point to a mapped polygon
The confirmed WGS84 longitude and latitude become a point-in-polygon query to USDA Soil Data Access. The response identifies the SSURGO map-unit polygon key and map-unit key at that coordinate. A ZIP code or named area is never treated as having one soil.
3. Map unit to components
The map-unit key joins USDA map-unit, component, horizon, texture, restriction, monthly-condition, and aggregated-attribute records. Every reported component is retained. Percentages describe the mapped unit and do not prove which component occurs at a particular square foot.
4. Normalization without invented values
USDA responses are converted into an application model before reaching the interface. Null and blank values become a distinct “not reported” state, never numeric zero. Ksat remains saturated hydraulic conductivity and is not relabeled as a field infiltration rate.
5. Caching and freshness
Non-personal soil profiles may be cached by USDA map-unit key for up to 30 days. The selected coordinate remains request state. Survey area, retrieval time, map-unit key, and completeness are shown with each result.
Appropriate use
The profile is useful for property research, landscape context, preliminary drainage questions, and understanding mapped conditions. It is not a soil test, septic perc test, wetland delineation, groundwater measurement, foundation analysis, or geotechnical investigation.