How to make an animation (or animated gif), from a number of geopandas plots-CodePudding

I have a Geodataframe ("mhg") in which the index are months (i.e. "2019-01-01", "2019-02-01", ...), and the GDF have a column that is the geometry of certain regions (i.e. POLYGON(...)), and finally another column that is the population corresponding to that geometry at that month.

sample data (with onyl two months) could be created by:

import geopandas as gpd 
data = [['2019-01-01', 'POLYGON(123...)', 1000], ['2019-01-01', 'POLYGON(456...)', 1500], ['2019-01-01', 'POLYGON(789...)', 1400], ['2019-02-01', 'POLYGON(123...)', 1100], ['2019-02-01', 'POLYGON(456...)', 1600], ['2019-02-01', 'POLYGON(789...)', 1300]]
mhg = gpd.GeoDataFrame(data, columns=['month','geometry', 'population'])
mhg.set_index('month')

I can make a multicolor plot of the users living in each region (all periods) with:

mhg.plot(column='population',cmap='jet')

and I can make the same, but filtering by month, using:

mhg.loc['2019-01-01'].plot(column='population',cmap='jet')

I would like to get some kind of ""animation" or animated gif where I can see the temporal evolution of the population, by using this kind of pseudocode:

for all the plots in
    mhg.loc['2019-01-01'].plot(column='population',cmap='jet')
    mhg.loc['2019-02-01'].plot(column='population',cmap='jet')
    mhg.loc['2019-03-01'].plot(column='population',cmap='jet')
    ...
then merge all plots into 1 animated gif

But I dont' know how to do it: the number of months can be up to hundreds, I don't how how to make the for loop, and I don't know even how to start...

Any suggestions?

EDIT: I tried the following (following https://linuxtut.com/en/c089c549df4d4a6d815c/):

months = np.sort(np.unique(mhg.month.values))
from matplotlib.animation import FuncAnimation
from matplotlib.animation import PillowWriter
fig, ax = plt.subplots()
ims = []
def update_fig(month):
    if len(ims) > 0:
        ims[0].remove()
        del ims[0]
    geos = mhg['geometry'].values
    users = mhg[(mhg.month==month)].population
    apl = gpd.plotting.plot_polygon_collection(ax, geos, population, True, cmap='jet')
    ims.append(apl)
    ax.set_title('month = '   str(month))
    return ims
anim = FuncAnimation(fig, update_fig, interval=1000, repeat_delay=3000, frames=months)
plt.show()

But I got a UserWarning: animation was deleted without rendering anything...

So I am stuck again.

CodePudding user response：

I managed to do it this way:

mhg = mhg.reset_index()
groups = mhg.groupby('month')
for month, grp in groups:                      
    grp.plot(column='users',cmap='jet',legend=True,figsize=(10, 10),norm=matplotlib.colors.LogNorm(vmin=mhg.users.min(), vmax=mhg.users.max()))
    plt.title({month})
    plt.xlim([-20, 5])
    plt.ylim([25, 45])
    plt.savefig("plot{month}.png".format(month=month), facecolor='white')
    plt.close()

And then I joined all the png's with convert (imagemagick tool):

convert -delay 50 -loop 0 *.png aniamtion.gif