ADR 002 — USDA Soil Data Access first

Status: Accepted · Date: 2026-08-01

Decision

Implement USDA Soil Data Access / SSURGO before SoilGrids.

Why

SDA provides an official, documented REST/POST query service and supports bounded point-to-map-unit lookup. It is first in the supplied U.S. integration priority, provides useful location context, and lets OpenSoil demonstrate map-unit/component/horizon provenance. SoilGrids' REST service is beta and its documentation recommends more dependable raster access for ingestion.

Consequences

The first response is mapped_survey, not measured or modeled. It supports only seven allowlisted properties and U.S. published survey coverage. The adapter warns about multi-component map units and does not treat component percentage as point probability. NCSS Lab Data Mart remains the next planned observed-data adapter.