Changing matplotlib subplot size/position after axes creation

Question

Is it possible to set the size/position of a matplotlib subplot after the axes are created? I know that I can do:

import matplotlib.pyplot as plt  ax = plt.subplot(111) ax.change_geometry(3,1,1) 

to put the axes on the top row of three. But I want the axes to span the first two rows. I have tried this:

import matplotlib.gridspec as gridspec  ax = plt.subplot(111) gs = gridspec.GridSpec(3,1) ax.set_subplotspec(gs[0:2]) 

but the axes still fill the whole window.

Update for clarity I want to change the position of an existing axes instance rather than set it when it is created. This is because the extent of the axes will be modified each time I add data (plotting data on a map using cartopy). The map may turn out tall and narrow, or short and wide (or something in between). So the decision on the grid layout will happen after the plotting function.

Answer 1

Thanks to Molly pointing me in the right direction, I have a solution:

import matplotlib.pyplot as plt import matplotlib.gridspec as gridspec  fig = plt.figure()  ax = fig.add_subplot(111)  gs = gridspec.GridSpec(3,1) ax.set_position(gs[0:2].get_position(fig)) ax.set_subplotspec(gs[0:2])              # only necessary if using tight_layout()  fig.add_subplot(gs[2])  fig.tight_layout()                       # not strictly part of the question  plt.show()