Dendrogram

Polar Phylogenetic Tree Light

Light theme polar phylogenetic dendrogram with scipy method

Output
Polar Phylogenetic Tree Light
Python
import matplotlib.pyplot as plt
import numpy as np
from scipy.cluster.hierarchy import dendrogram, linkage, set_link_color_palette

np.random.seed(123)

species = ['Human', 'Chimp', 'Gorilla', 'Orangutan', 'Macaque', 'Mouse', 
           'Rat', 'Dog', 'Cat', 'Cow', 'Pig', 'Horse']
n = len(species)
genetic_data = np.random.rand(n, 6) * 50
Z = linkage(genetic_data, method='average')

fig_temp, ax_temp = plt.subplots()
set_link_color_palette(['#27D3F5', '#F5276C', '#6CF527', '#F5B027', '#5314E6'])
dn = dendrogram(Z, labels=species, no_plot=False, color_threshold=0.6*max(Z[:,2]),
                above_threshold_color='#9ca3af', ax=ax_temp)
plt.close(fig_temp)

icoord = np.array(dn['icoord'])
dcoord = np.array(dn['dcoord'])
colors = dn['color_list']

x_min, x_max = icoord.min(), icoord.max()
y_max = dcoord.max()

def to_polar(x, y):
    theta = (x - x_min) / (x_max - x_min) * 2 * np.pi * 0.92 + np.pi * 0.04
    r = y / y_max * 0.65 + 0.3
    return theta, r

fig, ax = plt.subplots(figsize=(10, 10), subplot_kw={'projection': 'polar'}, facecolor='#ffffff')
ax.set_facecolor('#ffffff')

for ic, dc, color in zip(icoord, dcoord, colors):
    thetas, rs = [], []
    for x, y in zip(ic, dc):
        t, r = to_polar(x, y)
        thetas.append(t)
        rs.append(r)
    
    ax.plot([thetas[0], thetas[1]], [rs[0], rs[1]], color=color, linewidth=2.5, alpha=0.9)
    ax.plot([thetas[2], thetas[3]], [rs[2], rs[3]], color=color, linewidth=2.5, alpha=0.9)
    if thetas[1] != thetas[2]:
        arc_thetas = np.linspace(min(thetas[1], thetas[2]), max(thetas[1], thetas[2]), 40)
        ax.plot(arc_thetas, [rs[1]]*len(arc_thetas), color=color, linewidth=2.5, alpha=0.9)

leaf_positions = np.linspace(x_min, x_max, n)
for i, (pos, label) in enumerate(zip(leaf_positions, dn['ivl'])):
    theta, _ = to_polar(pos, 0)
    rotation = np.degrees(theta) - 90 if np.pi/2 < theta < 3*np.pi/2 else np.degrees(theta) + 90
    ha = 'right' if np.pi/2 < theta < 3*np.pi/2 else 'left'
    ax.text(theta, 0.2, label, ha=ha, va='center', fontsize=9, color='#4927F5',
            rotation=rotation, rotation_mode='anchor', fontweight='500')
    
    color = ['#27D3F5', '#F5276C', '#6CF527', '#F5B027', '#5314E6'][i % 5]
    ax.scatter(theta, 0.3, c=color, s=50, zorder=5, edgecolor='#ffffff', linewidth=1)

ax.set_ylim(0, 1.05)
ax.set_yticklabels([])
ax.set_xticklabels([])
ax.spines['polar'].set_visible(False)
ax.grid(True, color='#f3f4f6', alpha=0.8)

ax.set_title('Phylogenetic Circular Tree', fontsize=14, color='#1f2937', fontweight='bold', y=1.08)

plt.tight_layout()
plt.show()
Library

Matplotlib

Category

Statistical

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