fetchLDM: Query data from Kellogg Soil Survey Laboratory Data Mart via...

In soilDB: Soil Database Interface

Query data from Kellogg Soil Survey Laboratory Data Mart via Soil Data Access or local SQLite snapshot

Description

This function provides access to the Kellogg Soil Survey Laboratory Data Mart via Soil Data Access or a local SQLite snapshot. See details and examples for additional usage instructions.

Usage

fetchLDM(
  x = NULL,
  what = "pedlabsampnum",
  bycol = "pedon_key",
  tables = c("lab_physical_properties", "lab_chemical_properties",
    "lab_calculations_including_estimates_and_default_values", "lab_rosetta_Key"),
  WHERE = NULL,
  chunk.size = 1000,
  ntries = 3,
  layer_type = c("horizon", "layer", "reporting layer"),
  area_type = c("ssa", "country", "state", "county", "mlra", "nforest", "npark"),
  prep_code = c("S", ""),
  analyzed_size_frac = c("<2 mm", ""),
  dsn = NULL
)

Arguments

x	A vector of values to find in column specified by what, default NULL uses no constraints on what
what	A single column name from tables: lab_combine_nasis_ncss, lab_webmap, lab_site, lab_pedon or lab_area. Common choices include pedlabsampnum (Laboratory Pedon ID), upedonid (User Pedon ID), corr_name ('Correlated' Taxon Name), samp_name ('Sampled As' Taxon Name), or area_code (area symbol for specified lab_area records, see area_type).
bycol	A single column name from lab_layer used for processing chunks; default: "pedon_key"
tables	A vector of table names; Default is "lab_physical_properties", "lab_chemical_properties", "lab_calculations_including_estimates_and_default_values", and "lab_rosetta_Key". May also include one or more of: "lab_mir", "lab_mineralogy_glass_count", "lab_major_and_trace_elements_and_oxides", "lab_xray_and_thermal" but it will be necessary to select appropriate prep_code and analyzed_size_frac for your analysis (see Details).
WHERE	character. A custom SQL WHERE clause, which overrides x, what, and bycol, such as ⁠CASE WHEN corr_name IS NOT NULL THEN LOWER(corr_name) ELSE LOWER(samp_name) END = 'musick'⁠
chunk.size	Number of pedons per chunk (for queries that may exceed maxJsonLength)
ntries	Number of tries (times to halve chunk.size) before returning NULL; default 3
layer_type	Default: "horizon", "layer", and "reporting layer"
area_type	Default: "ssa" (Soil Survey Area). Other options include (choose one): "country", "state", "county", "mlra" (Major Land Resource Area), "nforest" (National Forest), "npark" (National Park)
prep_code	Default: "S" and "". May also include one or more of: "F", "HM", "HM_SK" "GP", "M", "N", or "S"
analyzed_size_frac	Default: "<2 mm" and "". May also include one or more of: "<0.002 mm", "0.02-0.05 mm", "0.05-0.1 mm", "0.1-0.25 mm", "0.25-0.5 mm", "0.5-1 mm", "1-2 mm", "0.02-2 mm", "0.05-2 mm"
dsn	Data source name; either a path to a SQLite database, an open DBIConnection or (default) NULL (to use soilDB::SDA_query)

Details

You can download SQLite or GeoPackage snapshots here: https://ncsslabdatamart.sc.egov.usda.gov/database_download.aspx. Specify the dsn argument to use a local copy of the lab data rather than Soil Data Access web service.

Lab Data Mart model diagram: https://jneme910.github.io/Lab_Data_Mart_Documentation/Documents/SDA_KSSL_Data_model.html If the chunk.size parameter is set too large and the Soil Data Access request fails, the algorithm will re-try the query with a smaller (halved) chunk.size argument. This will be attempted up to 3 times before returning NULL

The default behavior joins the lab_area tables only for the "Soil Survey Area" related records. You can specify alternative area records for use in x, what or WHERE arguments by setting area_type to a different value.

When requesting data from "lab_major_and_trace_elements_and_oxides", "lab_mineralogy_glass_count", or "lab_xray_and_thermal" multiple preparation codes (prep_code) or size fractions (analyzed_size_frac) are possible. The default behavior of fetchLDM() is to attempt to return a topologically valid (minimal overlaps) SoilProfileCollection. This is achieved by setting prep_code="S" ("sieved") and analyzed_size_frac="<2 mm". You may specify alternate or additional preparation codes or fractions as needed, but note that this may cause "duplication" of some layers where measurements were made with different preparation or on fractionated samples

Value

a SoilProfileCollection for a successful query, a try-error if no site/pedon locations can be found or NULL for an empty lab_layer (within sites/pedons) result

Examples

## Not run: 
  
  # fetch by Soil Survey Area area symbol (area_code using default "ssa" area_type)
  res <- fetchLDM("CA630", what = "area_code")
  
  # fetch by Major Land Resource area symbol (area_code using "mlra" area_type)
  res <- fetchLDM("22A", what = "area_code", area_type = "mlra")
  
  # fetch by multiple case-insensitive taxon name
  # (correlated or sampled as Musick or Holland series)
  res <- fetchLDM(WHERE = "(CASE WHEN corr_name IS NOT NULL 
                                THEN LOWER(corr_name) 
                                ELSE LOWER(samp_name) 
                            END) IN ('musick', 'holland')")

  # physical properties of soils correlated as taxonomic subgroup "Typic Argialbolls"
  res <- fetchLDM(x = "Typic Argialbolls", 
                  what = "corr_taxsubgrp", 
                  tables = "lab_physical_properties")


## End(Not run)

soilDB documentation built on April 3, 2025, 6:55 p.m.