Density Contour Plot — Matplotlib

A density contour plot (also known as a 2D KDE contour plot) displays the concentration of points in a 2D scatter plot using contour lines. The contours connect points of equal density, revealing clusters, patterns, and the overall bivariate distribution shape.

Density Contour Plot rendered with Matplotlib

Renders

Python source (Matplotlib)

""" anyplot.ai
contour-density: Density Contour Plot
Library: matplotlib 3.10.9 | Python 3.13.13
Quality: 79/100 | Updated: 2026-05-16
"""

import matplotlib.pyplot as plt
import numpy as np
from scipy import stats


# Data - bivariate distribution with two clusters
np.random.seed(42)

# Cluster 1: Main cluster centered around (5, 5)
n1 = 300
x1 = np.random.normal(5, 1.5, n1)
y1 = np.random.normal(5, 1.2, n1)

# Cluster 2: Secondary cluster centered around (9, 8)
n2 = 150
x2 = np.random.normal(9, 0.8, n2)
y2 = np.random.normal(8, 1.0, n2)

# Combine clusters
x = np.concatenate([x1, x2])
y = np.concatenate([y1, y2])

# Compute 2D kernel density estimation
xmin, xmax = x.min() - 1, x.max() + 1
ymin, ymax = y.min() - 1, y.max() + 1
xx, yy = np.mgrid[xmin:xmax:200j, ymin:ymax:200j]
positions = np.vstack([xx.ravel(), yy.ravel()])
values = np.vstack([x, y])
kernel = stats.gaussian_kde(values)
density = np.reshape(kernel(positions).T, xx.shape)

# Plot
fig, ax = plt.subplots(figsize=(16, 9))

# Filled contours for visual impact
contourf = ax.contourf(xx, yy, density, levels=12, cmap="Blues", alpha=0.8)

# Contour lines for clarity
contour = ax.contour(xx, yy, density, levels=12, colors="#306998", linewidths=1.5, alpha=0.9)

# Scatter plot overlay for context (smaller, semi-transparent points)
ax.scatter(x, y, s=30, alpha=0.3, color="#FFD43B", edgecolors="#306998", linewidths=0.5, zorder=5)

# Colorbar
cbar = plt.colorbar(contourf, ax=ax, shrink=0.85, pad=0.02)
cbar.set_label("Density", fontsize=18)
cbar.ax.tick_params(labelsize=14)

# Labels and styling
ax.set_xlabel("X Variable", fontsize=20)
ax.set_ylabel("Y Variable", fontsize=20)
ax.set_title("contour-density · matplotlib · pyplots.ai", fontsize=24)
ax.tick_params(axis="both", labelsize=16)
ax.grid(True, alpha=0.3, linestyle="--")

plt.tight_layout()
plt.savefig("plot.png", dpi=300, bbox_inches="tight")

Retrieve this implementation

Runnable source as JSON, for any HTTP client: https://api.anyplot.ai/specs/contour-density/matplotlib/code. Any spec id and library id listed in llms-full.txt fit the same URL shape; every URL below is complete and callable.

{
  "spec_id": "contour-density",
  "language": "python",
  "library": "matplotlib",
  "page": "https://anyplot.ai/contour-density/python/matplotlib",
  "hub": "https://anyplot.ai/contour-density",
  "code_json": "https://api.anyplot.ai/specs/contour-density/matplotlib/code",
  "spec_json": "https://api.anyplot.ai/specs/contour-density",
  "render_light_png": "https://storage.googleapis.com/anyplot-images/plots/contour-density/python/matplotlib/plot-light.png",
  "render_dark_png": "https://storage.googleapis.com/anyplot-images/plots/contour-density/python/matplotlib/plot-dark.png",
  "quality_score": 79.0,
  "license": "MIT",
  "guide": "https://anyplot.ai/llms.txt"
}

Part of Density Contour Plot on anyplot.ai.

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