USDA SSURGO¶
| Field | Current catalog entry |
|---|---|
| Provider | Soil Survey Geographic Database (SSURGO) |
| Organization | USDA Natural Resources Conservation Service |
| Coverage | Detailed published soil survey areas in the United States and territories |
| Data type | Mapped survey polygons, map units, components, horizons, properties, and interpretations |
| Properties | Texture, pH, organic matter, bulk density, available water, drainage, hydrology, interpretations, and many others; completeness varies |
| Spatial resolution | Vector map-unit delineations; survey scale and minimum delineation vary |
| Depths | Representative component horizons with variable centimeter boundaries |
| Access | Downloads, Web Soil Survey, Soil Data Access tabular and OGC services, derivative gSSURGO products |
| Authentication | None for the public access path selected by OpenSoil |
| Rate limits | No stable public quota is assumed; OpenSoil applies its own limits and bounded cache |
| License | Not yet encoded by OpenSoil; users must verify current USDA terms for their use |
| Citation | Cite USDA-NRCS SSURGO and the survey/product vintage used |
| OpenSoil status | supported through the USDA SDA point adapter |
Reliability and limitations¶
SSURGO is an authoritative survey product, but its representative map-unit values are not laboratory observations at arbitrary coordinates. A map unit can contain multiple components and inclusions. Survey vintage, scale, component percentages, horizon methods, and attribute completeness matter. OpenSoil returns mapped_survey, retains map-unit/component/horizon keys, and warns that component percent is not a point probability.