stat_wb_label: Label ranges under spectral curve.

In aphalo/ggspectra: Extensions to 'ggplot2' for Radiation Spectra

Label ranges under spectral curve.

Description

stat_wb_label computes the center of a waveband. Sets suitable default aesthetics for "text" and "label" geoms displaying "boundaries" and "names" of wavebands. x-scale transformations and axis flipping are currently not supported.

Usage

stat_wb_label(
  mapping = NULL,
  data = NULL,
  geom = "text",
  position = "identity",
  ...,
  by.group = FALSE,
  w.band = NULL,
  chroma.type = "CMF",
  label.fmt = "%s",
  ypos.fixed = 0,
  na.rm = TRUE,
  show.legend = NA,
  inherit.aes = TRUE
)

Arguments

mapping	The aesthetic mapping, usually constructed with aes or aes_. Only needs to be set at the layer level if you are overriding the plot defaults.
data	A layer specific dataset - only needed if you want to override the plot defaults.
geom	The geometric object to use display the data
position	The position adjustment to use for overlapping points on this layer
...	other arguments passed on to layer. This can include aesthetics whose values you want to set, not map. See layer for more details.
by.group	logical flag If TRUE repeated identical layers are added for each group within a plot panel as needed for animation. If FALSE, the default, a single layer is added per panel.
w.band	a waveband object or a list of waveband objects or numeric vector of at least length two.
chroma.type	character one of "CMF" (color matching function) or "CC" (color coordinates) or a chroma_spct object.
label.fmt	character string giving a format definition for formating the name of the waveband. sprintf.
ypos.fixed	numeric If not NULL used a constant value returned in y.
na.rm	a logical value indicating whether NA values should be stripped before the computation proceeds.
show.legend	logical. Should this layer be included in the legends? NA, the default, includes if any aesthetics are mapped. FALSE never includes, and TRUE always includes.
inherit.aes	If FALSE, overrides the default aesthetics, rather than combining with them. This is most useful for helper functions that define both data and aesthetics and shouldn't inherit behaviour from the default plot specification, e.g. borders.

Details

By default stat_wb_label() uses a panel function and ignores grouping as needed for annotation of layers supporting free axis scales. Passing by.group = TRUE as argument changes this behaviour adding the same layer repeatedly for each group as needed for constructing animated plots with functions from package 'gganimate'.

As colours are returned as RGB colour definitions, depending on the geometry used the use of scale_fill_identity and/or scale_colour_identity will be necessary for the correct colours to be displayed in the plot.

Value

A data frame with one row for each waveband object in the argument to w.band. Wavebeand outside the range of the spectral data are trimmed or discarded.

Computed variables

x

w.band-midpoint

wb.xmin

w.band minimum

wb.xmax

w.band maximum

y

ypos.fixed or zero

wb.color

color of the w.band

wb.name

label of w.band

wb.label

formatted wb.name

Default aesthetics

Set by the statistic and available to geoms.

label

..wb.label..

x

..x..

xmin

..wb.xmin..

xmax

..wb.xmax..

fill

..wb.color..

Required aesthetics

Required by the statistic and need to be set with aes().

x

numeric, wavelength in nanometres

Note

As only one colour scale can exist within a "gg" object, using this scale prevents the mapping to the colour aesthetic of factors in data to create a grouping.

See Also

fast_color_of_wb, which is used in the implementation.

Other stats functions: stat_color(), stat_find_qtys(), stat_find_wls(), stat_label_peaks(), stat_peaks(), stat_spikes(), stat_wb_box(), stat_wb_column(), stat_wb_contribution(), stat_wb_hbar(), stat_wb_irrad(), stat_wb_mean(), stat_wb_relative(), stat_wb_sirrad(), stat_wb_total(), stat_wl_strip(), stat_wl_summary()

Examples

library(photobiologyWavebands)
# ggplot() methods for spectral objects set a default mapping for x and y.
ggplot(sun.spct) +
  geom_line() +
  stat_wb_box(w.band = VIS(), ymin = -0.04, ymax = 0,
  color = "black", fill = "white") +
  stat_wb_label(w.band = VIS(), ypos.fixed = -0.02, color = "black")

ggplot(sun.spct) +
  geom_line() +
  stat_wb_hbar(w.band = PAR(), ypos.fixed = 0, linewidth = 1) +
  stat_wb_label(aes(color = after_stat(wb.color)),
                w.band = PAR(), ypos.fixed = +0.025) +
  scale_color_identity()

aphalo/ggspectra documentation built on June 10, 2025, 4:56 p.m.