Control vmin and vmax in Iris 'animate'?

Question

Does anyone know how (if?) I can control the vmin and vmax of an Iris quickplot pcolormesh animation using iris.experimental.animate.animate?

wind = iris.load_cube('/my/pp/file')
cube_iter = wind.slices(('longitude', 'latitude'))
ani = animate(cube_iter, qplt.contourf,vmin=0,vmax=20)
plt.show()

I'm using Iris version 2.4.0.

In this code, the animation works, but vmax is ignored (see attached screenshot).

Does anyone know how to fix this?

Thanks!

Answer 1

This is a bit of a fudge, but we can produce a more sensible animation by using the functools.partial function to fix the levels and extend keyword.

import functools

import iris
from iris.experimental.animate import animate
import iris.quickplot as qplt
import matplotlib.pyplot as plt

my_contourf = functools.partial(qplt.contourf, levels=range(260, 291, 5),
                                extend="both")
# Function defined by partial has no __module__ or __name__ attribute, so add
# them to get past iris animate's checks.
my_contourf.__module__ = "iris.quickplot"
my_contourf.__name__ = "contourf"

fname = iris.sample_data_path("E1_north_america.nc")
cube = iris.load_cube(fname)[:20]

cube_iter = cube.slices(('longitude', 'latitude'))
ani = animate(cube_iter, my_contourf, vmin=260, vmax=290)
ani.save("abc.gif")