Ecological Site Characterization from Coordinates: Free API Sources for Distributed Observatory Networks

@techreport{hamilton2026ecological, author = {Hamilton, Michael P., Ph.D.}, title = {Ecological Site Characterization from Coordinates: Free API Sources for Distributed Observatory Networks}, institution = {Canemah Nature Laboratory}, year = {2026}, number = {CNL-TN-2026-024}, month = {february}, url = {https://canemah.org/archive/document.php?id=CNL-TN-2026-024}, abstract = {Distributed ecological observatory networks require that every observation location be characterized by its ecological identity — elevation, climate classification, ecoregion, biome, land cover type, and vegetation community — without requiring the observer to know anything about the place beyond its GPS coordinates. We evaluate six freely available coordinate-based data sources for automated ecological site characterization: Open-Meteo Elevation API (Copernicus DEM, 90 m resolution, global), a Köppen climate classification service (0.25° resolution, global), EPA Omernik Ecoregions via ArcGIS REST (Levels I–IV, US coverage), USGS National Land Cover Database via ArcGIS REST (30 m resolution, CONUS), WWF Terrestrial Ecoregions (847 ecoregions in 14 biomes, global via shapefile), and iNaturalist taxon endpoints for establishment means and conservation status. All sources are free, require no API keys (except iNaturalist place-specific queries), and support direct coordinate-based queries or point-in-polygon lookup. We document the query syntax, response structure, resolution, coverage, and limitations of each source. We then describe a Python enrichment pipeline that populates the MacroscopeVR station database (`vf\_stations`) from coordinates alone, and discuss the extension of this approach to the SCOPE (Science Community Observatory for Participatory Ecology) framework, where thousands of citizen science observation points will require automated ecological classification at the time of capture. This capability transforms a GPS coordinate into an ecological address — the static identity layer upon which dynamic environmental data (CNL-TN-2026-023) and biodiversity observations are contextualized.} }