Calculate Rubification component of Profile Development Index after Harden (1982) "A quantitative index of soil development from field descriptions: Examples from a chronosequence in central California". Accepts vectorized inputs for hue, value and chroma to produce vector output. In Harden (1982) rubification is calculated relative to a reference parent material. Several other non-color components are normalized relative to a maximum value and summed to obtain the overall Profile Development Index.
harden.rubification(hue, chroma, hue_ref, chroma_ref)A character vector containing Munsell hues (e.g. "7.5YR")
A numeric vector containingMunsell chromas
A character vector containing Munsell hue(s) (e.g. "10YR") for reference material
A numeric vector containing Munsell chroma(s) for reference material
A numeric vector reflecting horizon redness increase relative to a reference (e.g. parent) material.