Download ZIP files containing spatial (ESRI shapefile) and tabular (TXT) files with standard
SSURGO format; optionally including the corresponding SSURGO Template Database with
include_template=TRUE.
downloadSSURGO(
WHERE = NULL,
areasymbols = NULL,
destdir = tempdir(),
exdir = destdir,
include_template = FALSE,
db = c("SSURGO", "STATSGO"),
extract = TRUE,
remove_zip = FALSE,
overwrite = FALSE,
quiet = FALSE
)character. Paths to downloaded ZIP files (invisibly). May not exist if remove_zip = TRUE.
character. A SQL WHERE clause expression used to filter records in sacatalog table.
Alternately WHERE can be any spatial object supported by SDA_spatialQuery() for defining
the target extent.
character. Character vector of soil survey area symbols e.g. c("CA067", "CA077"). Used
in lieu of WHERE argument.
character. Directory to download ZIP files into. Default tempdir().
character. Directory to extract ZIP archives into. May be a directory that does not yet exist.
Each ZIP file will extract to a folder labeled with areasymbol in this directory. Default:
destdir
logical. Include the (possibly state-specific) MS Access template database?
Default: FALSE
character. Either "SSURGO" (default; detailed soil map) or "STATSGO" (general soil map).
logical. Extract ZIP files to exdir? Default: TRUE
logical. Remove ZIP files after extracting? Default: FALSE
logical. Overwrite by re-extracting if directory already exists? Default:
FALSE
logical. Passed to curl::curl_download().
To specify the Soil Survey Areas you would like to obtain data you use a WHERE clause for query
of sacatalog table such as areasymbol = 'CA067', "areasymbol IN ('CA628', 'CA067')" or
areasymbol LIKE 'CT%'.
When db="STATSGO" the WHERE argument is not supported. Allowed areasymbols include
"US" and two-letter state codes e.g. "WY" for the Wyoming general soils map.
Pipe-delimited TXT files are found in /tabular/ folder extracted from a SSURGO ZIP.
The files are named for tables in the SSURGO schema. There is no header / the files do not have
column names. See the Soil Data Access Tables and Columns Report:
https://sdmdataaccess.nrcs.usda.gov/documents/TablesAndColumnsReport.pdf for details on
tables, column names and metadata including the default sequence of columns used in TXT files.
The function returns a try-error if the WHERE/areasymbols arguments result in
Several ESRI shapefiles are found in the /spatial/ folder extracted from a SSURGO ZIP. These
have prefix soilmu_ (mapunit), soilsa_ (survey area), soilsf_ (special features). There
will also be a TXT file with prefix soilsf_ describing any special features. Shapefile names
then have an a_ (polygon), l_ (line), p_ (point) followed by the soil survey area symbol.
createSSURGO()