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Copper classification according to Bray et al. (2015)

copper_group_bray.Rd

Classification of copper artefacts according to Bray et al. (2015) into one of 16 trace element compositional groups based on As, Sb, Ag, or Ni being below or above 0.1 wt%. Concentrations must be given in wt%.

Usage

copper_group_bray(
  df,
  elements = c(As = "As", Sb = "Sb", Ag = "Ag", Ni = "Ni"),
  id_sample = "ID",
  group_as_number = FALSE
)

Arguments

df

data frame with the data to be classified.

elements

named character vector with the column names of the As, Sb, Ag, and Ni concentrations.

id_sample

name of the column in df with the identifiers of each row. Default to ID.

group_as_number

logical. If FALSE, the default, copper groups are reported as their label. Otherwise, copper groups are reported by their number.

Value

The original data frame with the added column copper_group_bray.

References

Bray, P., Cuénod, A., Gosden, C., Hommel, P., Liu, P. and Pollard, A. M. (2015), Form and flow: the ‘karmic cycle’ of copper. Journal of Archaeological Science 56, pp. 202-209. https://doi.org/10.1016/j.jas.2014.12.013.

Examples

# create dataset
sample_df <- data.frame(
  ID = 1:3,
  As = c(0.2, 0.01, 0.15),
  Sb = c(0.00, 0.2, 0.11),
  Ag = c(0.00, 0.00, 0.12),
  Ni = c(0.00, 0.05, 0.20)
)
# classify copper groups
copper_group_bray(sample_df)
#>   ID   As   Sb   Ag   Ni copper_group_bray
#> 1  1 0.20 0.00 0.00 0.00                As
#> 2  2 0.01 0.20 0.00 0.05                Sb
#> 3  3 0.15 0.11 0.12 0.20       As+Sb+Ag+Ni

# classification with group number as output
copper_group_bray(sample_df, group_as_number = TRUE)
#>   ID   As   Sb   Ag   Ni copper_group_bray
#> 1  1 0.20 0.00 0.00 0.00                 2
#> 2  2 0.01 0.20 0.00 0.05                 3
#> 3  3 0.15 0.11 0.12 0.20                16