Download an OSSL subset and return an `ossl_library` artefact
Source:R/spectra-fetch.R
download_ossl_subset.RdFetches a region-filtered subset of the Open Soil Spectral Library
(Sanderman et al. 2024) and assembles it into the
`list(Xr, Yr, metadata)` shape consumed by
predict_ossl_mbl and
predict_ossl_plsr_local. The result is cached under
`tools::R_user_dir("soilKey", "cache")` so subsequent calls in the
same session (or future R sessions) skip the network.
Usage
download_ossl_subset(
region = c("global", "south_america", "north_america", "europe", "africa", "asia",
"oceania"),
properties = c("clay_pct", "sand_pct", "silt_pct", "cec_cmol", "bs_pct", "ph_h2o",
"oc_pct", "fe_dcb_pct", "caco3_pct"),
wavelengths = 350:2500,
endpoint = NULL,
cache_dir = NULL,
force = FALSE,
verbose = TRUE
)Arguments
- region
One of
"global","south_america","north_america","europe","africa","asia","oceania". Filters the OSSL training rows by their site coordinates' continent.- properties
Character vector of OSSL property names to keep in `Yr` (drops other reference columns to keep the artefact small). Defaults to the WRB-relevant set used by
fill_from_spectra.- wavelengths
Integer vector of wavelengths (nm) the returned
Xrmatrix will be interpolated to. Defaults to Vis-NIR/SWIR (350-2500 nm at 1-nm resolution, 2151 columns).- endpoint
OSSL HTTP endpoint serving the JSON manifest; overrideable via
options(soilKey.ossl_endpoint = ...)for testing or for using a private mirror. The default is the public Soil Spectroscopy GG bucket.- cache_dir
Cache directory; defaults to
tools::R_user_dir("soilKey", "cache").- force
If
TRUE, re-fetches even when a cached subset exists.- verbose
If
TRUE, emits a `cli` summary of the fetch.
Value
A list with elements Xr (numeric matrix, rows =
training profiles, columns = wavelengths in nm),
Yr (data.frame with the requested property columns,
rows aligned to Xr), and metadata (snapshot
date, region, n profiles, source URL, and the SHA-256 of
the cache file). Pass it as the ossl_library
argument to fill_from_spectra or
predict_ossl_mbl.