Extract Australian Soil Class data from TERN's API using Australian GPS coordinates

Extracts the Australian Soil Class data at the GPS points provided, assuming that they are land-based coordinates in Australia from the Australian Soil Class (ASC). Values for the Confusion Index, the amount of model certainty around the soil class at that grid cell, are also supported.

Usage

extract_asc(
  xy,
  locations = NULL,
  lonlat = NULL,
  confusion_index = FALSE,
  api_key = nert::get_key(),
  max_tries = 3L,
  initial_delay = 1L
)

Source

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ASC Data: https://data.tern.org.au/model-derived/slga/NationalMaps/SoilClassifications/ASC/90m/ASC_EV_C_P_AU_TRN_N.cog.tif
Confusion Index: https://data.tern.org.au/model-derived/slga/NationalMaps/SoilClassifications/ASC/90m/ASC_CI_C_P_AU_TRN_N.cog.tif

Arguments

xy: A list or data.frame object with names containing pairings of longitude and latitude values expressed as decimal degree values in that order. A data.frame may also be an sf points object. See Details for more.
locations: The column in which the location names are located as an Integer value. Defaults to 1.
lonlat: A vector of integer values indicating the column index in which the longitude and latitude values are contained. Defaults to 2:3.
confusion_index: Boolean, extract the values for the Confusion Index with the soil class? Defaults to FALSE and returns the soil class data only.
api_key: A character string containing your API key, a random string provided to you by TERN, for the request. Defaults to automatically detecting your key from your local .Renviron, .Rprofile or similar. Alternatively, you may directly provide your key as a string here or use functionality like that from keyring. If nothing is provided, you will be prompted on how to set up your R session so that it is auto-detected and a browser window will open at the TERN website for you to request a key.
max_tries: An integer Integer with the number of times to retry a failed download before emitting an error message. Defaults to 3.
initial_delay: An Integer with the number of seconds to delay before retrying the download. This increases as the tries increment. Defaults to 1.

Value

A data.table::data.table() with the provided GPS coordinates and the respective Australian Soil Class for the coordinates from the ASC data ("asc_longitude" and "asc_latitude").

xy

xy as a List Object

If xy is a list object, each individual vector's items should be named “x” (longitude) and “y” (latitude), respectively. The list item names should be descriptive of the individual vectors and will be included in a “location” column of the output.

xy as a Data Frame Object

If xy is a data.frame, it should be a three column object with the first column being the location name, the second longitude and the third, latitude both as decimal degrees in numeric format.

xy as an sf Object

If xy is an sf object, it should only be point geometry. If the data are projected, they will be reprojected to "EPSG:4326", Geographic Coordinate System WGS 84 before the extraction.

References

https://portal.tern.org.au/metadata/TERN/15728dba-b49c-4da5-9073-13d8abe67d7c

Examples

locs <- list(
  "Merredin" = c(x = 118.28, y = -31.48),
  "Corrigin" = c(x = 117.87, y = -32.33),
  "Tamworth" = c(x = 150.84, y = -31.07)
)

extract_asc(xy = locs, confusion_index = TRUE)
#> Error in h(simpleError(msg, call)): error in evaluating the argument 'y' in selecting a method for function 'extract': undefined columns selected