Abundances (should be logged already) are grouped into different levels, starting from the smallest values ("low") to the highest values ("high"). Intermediate abundances are either assigned as "mid", or "low-mid". If the range is too large, only "low" and "high" are assigned, the intermediate values are just numbers.
getAbundanceClass(x)Vector of numeric values (in log10)
Vector of factors corresponding to input with abundance class names (e.g. low, high)
Example: getAbundanceClass(c(12.4, 17.1, 14.9, 12.3)) ## --> factor(c("low", "high", "mid", "low"))