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Fetch USGS National Geochemical Database soil geochemistry

Source: R/taphonomy.R
morie_taphonomy_fetch_usgs_soil.Rd

Downloads the U.S. Geological Survey National Geochemical Database (soil) bulk CSV – real, open elemental concentrations (Ca, Fe, ...) that are the compositional analogue of pXRF bone/relic spectra. Use it to calibrate the compositional pipeline (morie_taphonomy_clr / morie_taphonomy_ilr / DML) on genuine open data before real scans exist. Dependency-free: the CSV is read straight from the zip with base R (no GDAL/sf); the WFS endpoint is GML-only and deliberately not used.

Usage

morie_taphonomy_fetch_usgs_soil(
  dest = tempdir(),
  nrows = 1000L,
  url = .MORIE_USGS_NGDBSOIL_URL,
  refresh = FALSE
)

Source

https://mrdata.usgs.gov/ngdb/soil/

Arguments

dest

Cache directory for the zip (default tempdir(); never ~).

nrows

Rows to read (default 1000 for a quick slice; NULL = all 1.5M+).

url

Source URL (default the USGS NGDB soil zip).

refresh

Re-download even if the cached zip exists.

Value

A data.frame of soil samples with elemental-concentration columns; attr(., "source") records the URL.

Details

The download is ~54 MB (482 MB uncompressed); it is cached in dest and reused unless refresh = TRUE. Network + size mean this never runs in examples/tests.

See also

morie_taphonomy_clr, morie_taphonomy_ilr

Examples

# \donttest{
# ~54 MB download:
# soil <- morie_taphonomy_fetch_usgs_soil(nrows = 500)
# }