convert_plot_density_axis: Express plotting data on the requested size axis

In mizer: Dynamic Multi-Species Size Spectrum Modelling

Express plotting data on the requested size axis

Description

Converts the size coordinate of the plotting data to the requested axis and, when the values are a density, multiplies them by the Jacobian that restates them in the density measure that axis calls for (see density_target_measure()). Values that are not a density are left alone.

Usage

convert_plot_density_axis(
  plot_dat,
  params,
  size_axis,
  density_wrt = NA_character_,
  per_log_size = NULL,
  species_col = "Species",
  value_col = 2
)

Arguments

plot_dat	A data frame of plotting data with a w column and a species column.
params	A MizerParams object providing the weight-length parameters.
size_axis	Either "w" (weight) or "l" (length).
density_wrt	The measure the values are a density with respect to, see density_measures. NA (the default) means the values are not a density.
per_log_size	Whether to express the values per logarithmic size. NULL (the default) keeps whichever the values already are.
species_col	Name of the column identifying the species. Default is "Species".
value_col	Name or index of the value column. Defaults to the second column.

Details

Anything involving a length is a per-species quantity, because the weight-length relationship is, so rows whose species is not one of the model's species — the "Total" row, for instance — are dropped when a length is needed. Going from a density per size to one per logarithmic size needs no length, and keeps those rows.

Value

The plotting data with its size coordinate, and where called for its values, expressed for the requested axis. The size coordinate is the first column.

mizer documentation built on Aug. 24, 2026, 9:08 a.m.