I am a hobbyist learning what python can do (and I am enjoying how much python can do!).

When drawing a circular networkx graph, that has arc3 connectionstyle edges, I noticed that the graph "shrank" when I set a high value for rad. Looking deeper, the graph had not shrunk. The x-axis and y-axis had lengthened.

Please refer to the graphs plotted by the code below.

I started with the top-left graph ('low-rad' of 0.5 and not having to set_ylim).

The top-right graph is the graph that 'shrank' when rad was set 'high' (rad=1).

Next, I manually set_ylim for the bottom two graphs.

The bottom-left graph looks like the top-left graph (I estimated the values for the ylim so that they look similar).

The bottom-right graph shows the intended 'high-rad' graph (the edges are high-arched).

Notice the axis ticks of each graph and compare the graphs' x-axis and y-axis data intervals. This suggests that matplotlib treats the 'high-rad' graphs as bigger than how human sees it. If the ticks were not there, I would not have known that the axis had lengthened (networkx switches off the ticks for x-axis and y-axis).

The expected outcome is the graph in the bottom right, without having to set (y-)axis limit (and without axis ticks).

I am using python 3.7.7 and matpotlib 3.2.2.

Thank you.

import networkx as nx
import matplotlib.pyplot as plt

shop_journey = [(1,2,3,4,5,6,7,8,9,10,11,12),(1,7),(7,1)]

G = nx.MultiDiGraph()
for journey in shop_journey:
    if len(journey) > 1:
        nx.add_path(G,journey)

def circle_pattern(ax,connectionstyle,bottom,top):
    pos=nx.circular_layout(G)
    nx.draw_networkx(
        G,
        pos=pos,
        connectionstyle=connectionstyle,
        ax=ax
    )
    ax.axis('equal')
    y1,y2 = tuple(ax.yaxis.get_data_interval())
    x1,x2 = tuple(ax.xaxis.get_data_interval())
    title='{}\nX-axis data interval: {},{}\nY-axis data interval: {},{}\nY-limits: {},{}'.format(
        connectionstyle,
        round(x1,1),round(x2,1),
        round(y1,1),round(y2,1),
        bottom,top
    )
    ax.set_title(label=title)
    ax.set_ylim(bottom,top)
    ax.tick_params(left=True,bottom=True,labelleft=True,labelbottom=True)

fig,axs = plt.subplots(2,2,figsize=(9,9))
circle_pattern(axs[0,0],"arc3,rad=0.5",None,None)
circle_pattern(axs[0,1],"arc3,rad=1",None,None)
circle_pattern(axs[1,0],"arc3,rad=0.5",-1.5,1.5)
circle_pattern(axs[1,1],"arc3,rad=1",-1.5,1.5)
plt.subplots_adjust(hspace=0.9)
plt.show()