Setup

from datetime import datetime as DT
from datetime import timedelta as TD
import math
from matplotlib.dates import DateFormatter as DF
import matplotlib.pyplot as plt
from matplotlib.ticker import PercentFormatter as PF
import numpy as np
import pandas as pd
import seaborn as sns

#Autumnal equinox was 2022.09.22 @ 9:03pm.
equinox = DT(2022, 9, 22, 21, 3, 0)
#Winter solstice will be 2022.12.21 @ 4:47pm.
solstice = DT(2022, 12, 21, 16, 47, 0)
leaf_range = (solstice - equinox).total_seconds()
seconds = leaf_range
seconds

7760640.0

leaves = []
dates = []
maxl = 0
for t in range(10000) :
    s = t/10000
    l = (s - 1) * math.log(1 - s)
    date = equinox + TD(seconds = seconds * s)
    leaves.append(l)
    dates.append(date)
    if l > maxl:
        maxl = l
        maxd = date

print(maxl, maxd)

0.3678794405969911 2022-11-18 15:41:20.544000

sns.set()

#Plot.    
fig = plt.figure(figsize = (13, 8))
ax = fig.add_subplot()

#Main Title.
ax.set_title("Leaves Changing and Falling", fontsize = 24)


ax.plot_date(x = dates,
             y = leaves,
             c = '#22A884FF',
             markersize = 5,
             zorder = 1)

ax.plot_date(x = [equinox, maxd, solstice],
             y = [0, 1/math.e, 0],
             c = '#414487FF',
             markersize = 10,
             zorder = 2)

ax.xaxis_date()
ax.set_xlabel(xlabel = "Autumnal Equinox to Winter Solstice", fontsize = 18)
ax.xaxis.set_major_formatter(DF('%b %d'))


ax.set_ylabel(ylabel = "Trees with Leaves Changing", fontsize = 18)
ax.yaxis.set_major_formatter(PF(1))
ax.tick_params(axis = 'both', rotation = 30, labelsize = 14)

#Annotations
texte = DT(2022, 9, 29, 12)
textd = DT(2022, 11, 2, 12)
texts = DT(2022, 12, 19, 12)

variables = [("36.79% of trees will", (textd, 0.30), "left"),
             ("have changing leaves", (textd, 0.28), "left"),
             ("at 15:41 on November 18th.", (textd, 0.26), "left"),
             ("21:03 on", (texte, 0.03), "left"),
             ("September 22nd.", (texte, 0.01), "left"),
             ("16:47 on", (texts, 0.03), "right"),
             ("December 21st.", (texts, 0.01), "right")]
    
for v in variables:
    plt.annotate(v[0], v[1],
                 c = '#414487FF',
                 fontsize = 20,
                 fontweight = "bold",
                 ha = v[2],
                 va = "bottom")

plt.savefig("2022.11.04 Classic.png")    

Rohan Lewis

2022.11.07