Reference

Coverage & datasets

Every collection Darly serves — region, resolution, products, license — plus source ranking and vertical-datum caveats.

Browse coverage interactively in the explorer, or query it from the STAC API (GET /collections). Collection IDs follow {country}-{agency}-{program}-{resolution}.

Collections

Collection ID	Region	Source	Resolution	Products	License
`usa-usgs-3dep-1m-seamless`	United States	USGS 3DEP (lidar)	1 m	DTM	Public domain (CC0)
`usa-usgs-3dep-1m`	United States	USGS 3DEP per-project DEMs (lidar)	1 m	DTM	Public domain (CC0)
`can-nrcan-hrdem-1m`	Canada (southern)	NRCan HRDEM (lidar)	1 m	DTM + DSM	Open Government Licence – Canada
`can-nrcan-hrdem-2m`	Canada (northern)	NRCan HRDEM (ArcticDEM)	2 m	DTM + DSM	Open Government Licence – Canada
`mex-inegi-lidar-1-5m`	Mexico (urban areas)	INEGI lidar	1.5 m	DTM + DSM	INEGI Terms of Free Use
`mex-inegi-lidar-5m`	Mexico	INEGI lidar	5 m	DTM + DSM	INEGI Terms of Free Use
`glo-esa-copdem-30m`	Global	ESA Copernicus DEM (GLO-30)	30 m	DSM	ESA/Airbus free license
`glo-ogh-gedtm-30m`	Global	OpenGeoHub GEDTM	30 m	DTM	CC-BY 4.0
`sam-ufrgs-anadem-30m`	South America	UFRGS/ANA ANADEM	30 m	DTM	CC-BY 4.0

Lidar collections cover their programs' published extents, not every square meter of the country — check the explorer or search the catalog with your AOI to see what's indexed where.

How coverage affects elevation queries

The Elevation API ranks candidate collections finest-first at every location, falling through on nodata:

Lidar first — 1 m before 1.5 m before 2 m before 5 m.
The 30 m datasets last, regional before global: for surface=dtm, sam-ufrgs-anadem-30m answers in South America (its vegetation-bias correction is calibrated for the continent) and glo-ogh-gedtm-30m everywhere else; glo-esa-copdem-30m for surface=dsm.

Equal-resolution ties break to the collection with the smaller coverage extent, so regional products are preferred over global fallbacks wherever they apply — pass collections explicitly to override. The two USA 1 m collections are the exception: the seamless mosaic always answers before the per-project tiles it was built from, and the per-project collection fills in where the mosaic has no coverage yet.

Queries on land within a dataset's published extent normally fall back to a 30 m global product, and queries in covered lidar areas get the good stuff automatically. Open ocean and locations outside the selected product's extent (including DTM queries south of GEDTM's roughly 65°S limit) return null. The response's collection and resolution fields tell you which source answered.

Note the surface split: 3DEP publishes DTM only, Copernicus is DSM only. A surface=dsm query in the USA falls to Copernicus 30 m; a surface=dtm query almost anywhere in CONUS gets 1 m lidar.

Vertical datums

Output datums are egm2008 (default) and wgs84_ellipsoid — see the vertical_datum option. Conversions from each source's native datum use geoid grids with limited footprints:

NAVD88 grids cover CONUS only. Sources published on NAVD88 can't be datum-shifted in Alaska, Hawaii, or Mexico; those pixels fall through to the next collection (typically the global 30 m datasets) rather than returning a wrong height.
WGS84 is a datum ensemble: wgs84_ellipsoid heights carry roughly ±2 m of realization ambiguity and are not survey-grade.

Coming next

France (IGN LiDAR HD), Germany (state programs), and New Zealand (LINZ) are queued — the same collection contract, so pystac-client code and elevation queries pick them up without changes. Want a dataset prioritized? Tell us: [email protected].