Plotting subfigures using matplotlib seems quite simple. It becomes more difficult, when I try to define insets at certain coordinates within the main image.

Using

fig.add_subplot(121, posiiton=[0.4,0.4, 0.2,0.2])

I can define the position of the subplot, which can deviate from the grid that is defined in the first parameter. The coordinates are in the range [0:1].

I've figured out how to make insets using real coordinates but my solution seems a bit tricky (see attachment). Did I miss the easy way to do it?