CalibDataAlien {IsoriX}

Simulated calibration dataset

Description

This dataset contains simulated hydrogen delta values for corresponding locations based on an assumed linear relationship between the animal tissue value and the hydrogen delta values in the environment. The data can be used as an example to fit a calibration model using the function [calibfit].

Format

A *dataframe* with x observations on 6 variables:

[, 1]	site_ID	(*factor*)	Identification of the sampling site
[, 2]	long	(*numeric*)	Longitude coordinate (decimal degrees)
[, 3]	lat	(*numeric*)	Latitude coordinate (decimal degrees)
[, 4]	elev	(*numeric*)	Elevation asl (m)
[, 5]	sample_ID	(*factor*)	Identification of the sampled animal
[, 6]	tissue.value	(*numeric*)	Hydrogen delta value of the tissue

Details

Users who wish to use their own dataset for calibration should create a *dataframe* of similar structure than this one. The columns should possess the same names as the ones described above. If the elevation is unknown at the sampling sites, elevation information can be extracted from a high resolution elevation raster using the function [terra::extract]. In this dataset, we retrieved elevations from the Global Multi-resolution Terrain Elevation Data 2010.

See Also

[calibfit] to fit a calibration model

Examples

head(CalibDataAlien)
str(CalibDataAlien)

## The examples below will only be run if sufficient time is allowed
## You can change that by typing e.g. options_IsoriX(example_maxtime = XX)
## if you want to allow for examples taking up to ca. XX seconds to run
## (so don't write XX but put a number instead!)

if (getOption_IsoriX("example_maxtime") > 30) {
  ## We prepare the precipitation data
  GNIPDataDEagg <- prepsources(data = GNIPDataDE)

  ## We fit the models for Germany
  GermanFit <- isofit(data = GNIPDataDEagg)

  ## We build the isoscape
  GermanScape <- isoscape(raster = ElevRasterDE, isofit = GermanFit)

  ## We create a simulated dataset with 50 site and 10 observations per site
  set.seed(2L)
  CalibDataAlien <- create_aliens(
    calib_fn = list(intercept = 3, slope = 0.5, resid_var = 5),
    isoscape = GermanScape,
    raster = ElevRasterDE,
    n_sites = 50,
    min_n_samples = 10,
    max_n_samples = 10
  )
  plot(sample_value ~ source_value, data = CalibDataAlien)
  abline(3, 0.5)

  CalibDataAlien$source_value <- NULL

  ## Uncomment the following to store the file as we did
  # save(CalibDataAlien, file = "CalibDataAlien.rda", compress = "xz")
}