I can force the axis to be equally scaled via:
ax = Axis(fig[1, 1], aspect=DataAspect())
But have not yet figured out, if there is an elegant way to have also equally spaced ticks on both axis.
In plotly /PlotlyJS I can specify a parameter dtick, it is not elegant, but it works. On Makie I am lost …
P.S.:
The reason for this question is the axis-layout for Nyquist plots, see here