I think the second graph of https://pvlib-python.readthedocs.io/en/stable/gallery/shading/plot_passias_diffuse_shading.html is incorrect, even though it corresponds ...
# changes based on a vertical offset between rows caused by sloped terrain. # It uses :py:func:`pvlib.tracking.calc_axis_tilt` and # :py:func:`pvlib.tracking.calc_cross_axis_tilt` to calculate the ...