The same plot in 14 other libraries — Python: Altair, Bokeh, lets-plot, Matplotlib, Plotly, plotnine, Pygal, Seaborn; Julia: Makie.jl; JavaScript: Chart.js, D3.js, Apache ECharts, Highcharts, MUI X Charts. Compare all 15 side by side: Basic Contour Plot in Python, R, Julia and JavaScript.
A contour plot displays isolines (level curves) of a 2D scalar field, connecting points of equal value across a surface. It transforms 3D data into an intuitive 2D representation, making it easy to identify regions of high and low values, gradients, and patterns. Contour plots are essential for visualizing continuous surfaces where the relationship between X, Y coordinates and a Z value needs to be understood.
#' anyplot.ai
#' contour-basic: Basic Contour Plot
#' Library: ggplot2 3.5.1 | R 4.4.1
#' Quality: 90/100 | Created: 2026-06-25
library(ggplot2)
library(ragg)
set.seed(42)
# Theme tokens
THEME <- Sys.getenv("ANYPLOT_THEME", "light")
PAGE_BG <- if (THEME == "light") "#FAF8F1" else "#1A1A17"
ELEVATED_BG <- if (THEME == "light") "#FFFDF6" else "#242420"
INK <- if (THEME == "light") "#1A1A17" else "#F0EFE8"
INK_SOFT <- if (THEME == "light") "#4A4A44" else "#B8B7B0"
DIV_MID <- if (THEME == "light") "#FAF8F1" else "#1A1A17"
# Data: ocean temperature anomaly on a 60x60 regular grid
resolution <- 60
x_vals <- seq(-3, 3, length.out = resolution)
y_vals <- seq(-3, 3, length.out = resolution)
grid <- expand.grid(x = x_vals, y = y_vals)
grid$temp <- (
2.8 * exp(-((grid$x - 1.2)^2 + (grid$y - 0.8)^2) / 1.5) +
1.6 * exp(-((grid$x + 1.5)^2 + (grid$y - 1.3)^2) / 2.0) -
2.2 * exp(-((grid$x - 0.3)^2 + (grid$y + 1.9)^2) / 1.2) -
1.5 * exp(-((grid$x + 1.8)^2 + (grid$y + 0.6)^2) / 1.8)
)
# Title
title_text <- "contour-basic · r · ggplot2 · anyplot.ai"
# Plot
p <- ggplot(grid, aes(x = x, y = y)) +
geom_tile(aes(fill = temp)) +
geom_contour(aes(z = temp), color = INK, linewidth = 0.4, alpha = 0.7, bins = 12) +
scale_fill_gradient2(
low = "#AE3030",
mid = DIV_MID,
high = "#4467A3",
midpoint = 0,
name = "ΔT (°C)"
) +
coord_fixed() +
labs(
title = title_text,
x = "Longitude",
y = "Latitude"
) +
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.major = element_blank(),
panel.grid.minor = element_blank(),
panel.border = element_rect(color = INK_SOFT, fill = NA),
axis.title = element_text(color = INK, size = 10),
axis.text = element_text(color = INK_SOFT, size = 8),
plot.title = element_text(color = INK, size = 12),
legend.background = element_rect(fill = ELEVATED_BG, color = INK_SOFT),
legend.text = element_text(color = INK_SOFT, size = 8),
legend.title = element_text(color = INK, size = 10),
plot.margin = margin(20, 20, 20, 20)
)
# Save (square canvas: 6×6 in @ 400 dpi = 2400×2400 px)
ggsave(
filename = sprintf("plot-%s.png", THEME),
plot = p,
device = ragg::agg_png,
width = 6,
height = 6,
units = "in",
dpi = 400
)
Runnable source as JSON, for any HTTP client: https://api.anyplot.ai/specs/contour-basic/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": "contour-basic",
"language": "r",
"library": "ggplot2",
"page": "https://anyplot.ai/contour-basic/r/ggplot2",
"hub": "https://anyplot.ai/contour-basic",
"code_json": "https://api.anyplot.ai/specs/contour-basic/ggplot2/code",
"spec_json": "https://api.anyplot.ai/specs/contour-basic",
"render_light_png": "https://storage.googleapis.com/anyplot-images/plots/contour-basic/r/ggplot2/plot-light.png",
"render_dark_png": "https://storage.googleapis.com/anyplot-images/plots/contour-basic/r/ggplot2/plot-dark.png",
"quality_score": 90.0,
"license": "MIT",
"guide": "https://anyplot.ai/llms.txt"
}Part of Basic Contour Plot on anyplot.ai.