How to label multiple histograms in AlgebraOfGraphics

Specific Domains Visualization
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1

I have a dataset where each column is a list of occurrences. I would like to plot three columns as three histograms within one figure, but I cannot wrap my head around the AlgebraOfGraphics idioms.

Within Makie.jl, I would do

fig = Figure()
ax = Axis(fig[1,1])

hist!(ax, df[:pf],  label = "Plasma frame")
hist!(ax, df[:sf],  label = "Shock frame")
hist!(ax, df[:ISM], label = "ISM frame")

axislegend(ax)

fig

where df is my data source and each of df[:pf], df[:sf], and df[:ISM] is a Vector.

With AlgebraOfGraphics.jl, I’ve tried

using AlgebraOfGraphics
import AlgebraOfGraphics as AoG

data = AoG.data(df)
m = AoG.mapping(:pf  => "Plasma frame") +
    AoG.mapping(:sf  => "Shock frame")  +
    AoG.mapping(:ISM => "ISM frame")
hist_layer = AoG.histogram()

layer = data * m * hist_layer

The issue I’m having is with labeling each histogram. I know the => Pair syntax labels the axes, but I couldn’t figure out how to add data series labels from the AoG documentation.

2

The plain label is done via visual(label = "label") but then you have to do the colors yourself. Easier would be to pass your three columns as a vector and then use dims(1) for color, check this tutorial for reference Intro to AoG - V - Alternative input data formats | AlgebraOfGraphics