Synthetic OSSL South America demo subset

A small, deterministic, OSSL-shaped artefact for use in vignettes, examples and tests when the real Open Soil Spectral Library data is not available (no network, sensitive deployment, CI). The object has the canonical list(Xr, Yr, metadata) shape consumed by predict_ossl_mbl / fill_from_spectra, so the in-package demo path is identical to the real-data path.

Usage

ossl_demo_sa

Format

A list with three elements:

Xr

Numeric matrix, 80 rows (synthetic profiles) x 2151 columns (wavelengths 350-2500 nm). Reflectance values in [0.05, 0.85].

Yr

Data frame, 80 rows x 9 columns (clay_pct, sand_pct, silt_pct, cec_cmol, bs_pct, ph_h2o, oc_pct, fe_dcb_pct, caco3_pct). Property ranges follow the OSSL global summary statistics.

metadata

Named list with provenance information (region, n_profiles, snapshot, seed, note, ...).

Source

Synthetic; built by data-raw/build_ossl_demo.R with seed 20260430. The OSSL property ranges that drove the simulation come from Sanderman, J. et al. (2024), Open Soil Spectral Library, https://soilspectroscopy.org/.

Details

This is a synthetic placeholder: the spectra are generated from a tropical-soil baseline plus property-correlated absorption bands (1400 nm OH-water, 1900 nm clay-OH, 2200 nm Al-OH, 900 nm Fe-oxide) with deterministic noise. It is not a substitute for real OSSL measurements. For paper-grade work, populate a real OSSL artefact via:

  ossl_lib <- download_ossl_subset(region = "south_america")

Re-build the demo with source("data-raw/build_ossl_demo.R").

Examples

data(ossl_demo_sa)
dim(ossl_demo_sa$Xr)
#> [1]   80 2151
#> [1]   80 2151
head(ossl_demo_sa$Yr)
#>   clay_pct sand_pct  silt_pct  cec_cmol   bs_pct   ph_h2o    oc_pct fe_dcb_pct
#> 1 51.12727 26.36293  9.933215  1.709790 54.60047 6.786708 0.8673316   2.059861
#> 2 30.62185 27.79992 37.570483 14.413831 58.24193 6.281825 1.3189863   4.060600
#> 3 29.88843 30.69563 33.931396  4.113563 27.34664 5.104516 1.4601632   6.356726
#> 4 75.08242 13.04921 17.215618  2.705566 30.37244 6.384495 0.9846567   5.511491
#> 5 27.30663 40.20213 14.251883  3.807958 34.64959 5.553904 1.5314590   3.884158
#> 6 52.19720 22.55893 34.456830  4.106666 29.00926 5.789555 0.8038034   5.912470
#>   caco3_pct
#> 1 0.4831520
#> 2 0.3862360
#> 3 0.3492779
#> 4 0.7161103
#> 5 0.1526625
#> 6 0.1480898

if (FALSE) { # \dontrun{
# Use it as the ossl_library argument to predict_ossl_mbl():
pedon <- make_synthetic_pedon_with_spectra()
fill_from_spectra(pedon,
                  library      = "ossl",
                  method       = "mbl",
                  ossl_library = ossl_demo_sa)
} # }