How to create Animations

Section author: Florian Zill (Helmholtz Centre for Environmental Research GmbH - UFZ)

To demonstrate the creation of an animated plot we use a component transport example from the ogs benchmark gallery (https://www.opengeosys.org/docs/benchmarks/hydro-component/elder/).

import numpy as np

from ogstools.meshplotlib import examples, setup
from ogstools.meshplotlib.animation import animate
from ogstools.propertylib import Scalar

setup.reset()
mesh_series = examples.meshseries_CT_2D
mesh_property = Scalar(
    data_name="Si", data_unit="", output_unit="%", output_name="Saturation"
)

To read your own data as a mesh series you can do:

from ogstools.meshlib import MeshSeries
mesh_series = MeshSeries("filepath/filename_pvd_or_xdmf")

You can also use a property from the available presets instead of needing to create your own: Property Presets

Let’s use fixed scale limits to prevent rescaling during the animation.

setup.p_min = 0
setup.p_max = 100
setup.dpi = 50

You can choose which timesteps to render by passing either an int array corresponding to the indices, or a float array corresponding to the timevalues to render. If a requested timevalue is not part of the timeseries it will be interpolated. In this case every second frame will be interpolated.

timevalues = np.linspace(
    mesh_series.timevalues[0], mesh_series.timevalues[-1], num=25
)

Now, let’s animate the saturation solution. A timescale at the top indicates existing timesteps and the position of the current timevalue. Note that rendering many frames in conjunction with large meshes might take a really long time.

titles = [f"{tv/(365.25*86400):.1f} yrs" for tv in timevalues]
anim = animate(mesh_series, mesh_property, timevalues, titles)

Once Loop Reflect

The animation can be saved (as mp4) like so:

from ogstools.meshplotlib.animation import save_animation
save_animation(anim, "Saturation", fps=5)