2D Histogram Heatmap — ggplot2

A two-dimensional histogram that displays the joint distribution of two continuous variables as a heatmap with rectangular bins. Each bin's color intensity represents the frequency or count of data points falling within that region, making it ideal for revealing density patterns, clusters, and correlations in bivariate data. Unlike scatter plots that can become cluttered with large datasets, 2D histograms effectively summarize point density.

2D Histogram Heatmap rendered with ggplot2

Renders

R source (ggplot2)

#' anyplot.ai
#' histogram-2d: 2D Histogram Heatmap
#' Library: ggplot2 3.5.1 | R 4.4.1
#' Quality: 82/100 | Created: 2026-09-05

library(ggplot2)
library(tibble)
library(ragg)

set.seed(42)

# --- Theme tokens -----------------------------------------------------------
THEME       <- Sys.getenv("ANYPLOT_THEME", "light")
PAGE_BG     <- if (THEME == "light") "#FAF8F1" else "#1A1A17"
INK         <- if (THEME == "light") "#1A1A17" else "#F0EFE8"
INK_SOFT    <- if (THEME == "light") "#4A4A44" else "#B8B7B0"

# --- Data --------------------------------------------------------------------
# Daily returns (%) for two correlated asset classes: equities vs. bonds.
n <- 20000
equity_returns <- rnorm(n, mean = 0.05, sd = 1.2)
bond_returns <- 0.35 * equity_returns + rnorm(n, mean = 0.02, sd = 0.5)

df <- tibble(equity_returns = equity_returns, bond_returns = bond_returns)

# --- Plot ---------------------------------------------------------------------
title_text <- "histogram-2d · r · ggplot2 · anyplot.ai"

p <- ggplot(df, aes(x = equity_returns, y = bond_returns)) +
  geom_bin2d(bins = 28) +
  scale_fill_gradient(
    low = "#009E73",
    high = "#4467A3",
    name = "Count",
    trans = "sqrt",
    labels = scales::label_comma()
  ) +
  stat_density_2d(color = INK_SOFT, linewidth = 0.25, alpha = 0.5) +
  labs(
    title = title_text,
    x = "Equity Daily Return (%)",
    y = "Bond Daily Return (%)"
  ) +
  theme_minimal(base_size = 8) +
  theme(
    plot.background   = element_rect(fill = PAGE_BG, color = PAGE_BG),
    panel.background  = element_rect(fill = PAGE_BG, color = NA),
    panel.grid        = element_blank(),
    axis.title        = element_text(color = INK, size = 10),
    axis.text         = element_text(color = INK_SOFT, size = 8),
    axis.line         = element_line(color = INK_SOFT),
    plot.title        = element_text(color = INK, size = 12),
    legend.title      = element_text(color = INK, size = 10),
    legend.text       = element_text(color = INK_SOFT, size = 8),
    legend.key.height = unit(0.35, "in")
  )

# --- Save ----------------------------------------------------------------------
ggsave(
  filename = sprintf("plot-%s.png", THEME),
  plot     = p,
  device   = ragg::agg_png,
  width    = 6,
  height   = 6,
  units    = "in",
  dpi      = 400
)

Retrieve this implementation

Runnable source as JSON, for any HTTP client: https://api.anyplot.ai/specs/histogram-2d/ggplot2/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": "histogram-2d",
  "language": "r",
  "library": "ggplot2",
  "page": "https://anyplot.ai/histogram-2d/r/ggplot2",
  "hub": "https://anyplot.ai/histogram-2d",
  "code_json": "https://api.anyplot.ai/specs/histogram-2d/ggplot2/code",
  "spec_json": "https://api.anyplot.ai/specs/histogram-2d",
  "render_light_png": "https://storage.googleapis.com/anyplot-images/plots/histogram-2d/r/ggplot2/plot-light.png",
  "render_dark_png": "https://storage.googleapis.com/anyplot-images/plots/histogram-2d/r/ggplot2/plot-dark.png",
  "quality_score": 82.0,
  "license": "MIT",
  "guide": "https://anyplot.ai/llms.txt"
}

Part of 2D Histogram Heatmap on anyplot.ai.

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