kwg-environment

KnowWhereGraph Environment

Environmental observation layers from KnowWhereGraph, covering SSURGO soils, the USDA Cropland Data Layer, EPA air quality measurements, and NOAA climate division observations for the United States.

KnowWhereGraph Environment is one of four graphs that republish KnowWhereGraph (KWG) version 4, the "Santa Barbara" release, from a November 2024 snapshot. It holds the soil, land cover, air quality, and climate layers, and is the largest of the four; the companion graphs are kwg-places, kwg-hazards, and kwg-society.

Contents, with the coverage KWG documents for each source:

  • USDA Soil Survey Geographic Database (SSURGO): soil map units with their polygon geometries, soil types, and soil properties
  • USDA Cropland Data Layer (CropScape): crop and land cover types observed per level 13 S2 cell per year, from 2008
  • EPA Air Quality System: monitoring sites, with addresses, and daily summaries for lead, CO, ozone, PM2.5, NO2, SO2, and PM10, from 1980
  • NOAA climate divisions for the contiguous US and their observations (temperature, precipitation, drought severity indices, heating and cooling degree days), from 1895, with QUDT units
  • Shared time:Instant entities for years and dates

Observations follow SOSA (features of interest, observable properties, observations, and results) and OWL-Time. Features are located with KWG's spatial relations (kwg-ont:sfWithin, kwg-ont:sfContains, kwg-ont:sfOverlaps) to S2 cells and to administrative regions, asserted in both directions. Cropland is the largest layer by statement count, and air quality the second; soil is dominated by its geometries.

Resource IRIs are under http://stko-kwg.geog.ucsb.edu/lod/resource/. Administrative regions and other places are referenced by IRI and described in kwg-places. S2 cells appear only through their relations to features and observations; their own types, labels, and geometries are not included. The SAWGraph spatialkg graph uses the same S2 cell IRIs.

Each KWG source subgraph is kept as a named graph, http://stko-kwg.geog.ucsb.edu/lod/resource/subgraph.<name> (for example subgraph.air-quality-epa). The KWG ontology modules for these layers and the vocabularies they reuse (SOSA, OWL-Time, GeoSPARQL, QUDT, FIBO addresses and locations) are included, each in a named graph named by its ontology IRI.

KnowWhereGraph's own contribution is released under CC0. The underlying sources keep their own terms, which should be checked with each provider.