A radar chart (also known as spider or web chart) displays multivariate data on axes starting from a common center point, with values connected to form a polygon. Each axis represents a different variable, making it ideal for comparing multiple quantitative variables at once or visualizing strengths and weaknesses across categories.
#' anyplot.ai
#' radar-basic: Basic Radar Chart
#' Library: ggplot2 3.5.1 | R 4.4.1
#' Quality: 78/100 | Created: 2026-07-24
library(ggplot2)
library(dplyr)
library(ragg)
set.seed(42)
# coord_polar() curves straight edges into arcs; radar polygons need straight
# lines between vertices, so force linear interpolation via a custom coord.
coord_radar <- function(theta = "x", start = 0, direction = 1) {
theta <- match.arg(theta, c("x", "y"))
r <- if (theta == "x") "y" else "x"
# clip = "off": CoordPolar defaults to clip = "on", which hard-clips
# panel content to the circular/hexagonal boundary. The category-label
# layer sits close to that boundary (label_radius near the y-scale max),
# and its text bounding box — laid out horizontally, not radially — pokes
# past the boundary on off-axis vertices, silently shaving off whichever
# glyph sits at the extreme edge (e.g. the leading "P" of a left-side
# label). Disabling clip removes that failure mode entirely.
ggproto("CoordRadar", CoordPolar,
theta = theta, r = r, start = start,
direction = sign(direction),
is_linear = function(coord) TRUE,
clip = "off"
)
}
# --- 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"
GRID_COLOR <- scales::alpha(INK, 0.15)
# Imprint palette (see prompts/default-style-guide.md "Categorical Palette")
IMPRINT_PALETTE <- c("#009E73", "#C475FD", "#4467A3", "#BD8233",
"#AE3030", "#2ABCCD", "#954477", "#99B314")
# --- Data -----------------------------------------------------------------
competencies <- c("Communication", "Technical Skills", "Teamwork",
"Leadership", "Problem Solving", "Adaptability")
n_axes <- length(competencies)
reviews <- tibble::tibble(
competency = rep(competencies, 2),
employee = factor(rep(c("Alice Chen", "Marcus Webb"), each = n_axes),
levels = c("Alice Chen", "Marcus Webb")),
score = c(85, 70, 90, 60, 80, 75,
60, 88, 68, 92, 74, 82)
) %>%
mutate(axis_pos = rep(seq_len(n_axes), 2))
# Duplicate each series' first point at n_axes + 1 to close the polygon
closing_points <- reviews %>%
filter(axis_pos == 1) %>%
mutate(axis_pos = n_axes + 1)
radar_df <- bind_rows(reviews, closing_points)
# Category labels are drawn as a manual geom_text() layer, not axis.text.x:
# ggplot2's CoordPolar computes a per-angle hjust for axis text, and at
# certain angles that computation clips/mis-renders the leading glyph.
# A fixed hjust/vjust text layer sidesteps that rendering path entirely.
label_df <- tibble::tibble(
axis_pos = seq_len(n_axes),
competency = competencies
)
label_radius <- 108
# --- Plot -------------------------------------------------------------------
p <- ggplot(radar_df, aes(x = axis_pos, y = score, group = employee)) +
geom_polygon(aes(fill = employee), color = NA, alpha = 0.25) +
geom_line(aes(color = employee), linewidth = 1.1) +
geom_point(aes(color = employee), size = 2.8) +
geom_text(data = label_df,
aes(x = axis_pos, y = label_radius, label = competency),
inherit.aes = FALSE, color = INK, size = 3.9,
hjust = 0.5, vjust = 0.5) +
coord_radar(theta = "x", start = 0) +
scale_x_continuous(breaks = seq_len(n_axes), labels = competencies,
limits = c(1, n_axes + 1), expand = c(0, 0)) +
scale_y_continuous(limits = c(0, 120), breaks = seq(0, 100, 20),
expand = c(0, 0)) +
scale_fill_manual(values = IMPRINT_PALETTE[1:2], name = NULL) +
scale_color_manual(values = IMPRINT_PALETTE[1:2], name = NULL) +
labs(title = "radar-basic · r · ggplot2 · anyplot.ai",
subtitle = "Score (0-100 scale)") +
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_line(color = GRID_COLOR, linewidth = 0.4),
panel.grid.minor = element_blank(),
axis.title = element_blank(),
axis.text.x = element_blank(),
axis.text.y = element_text(color = INK_SOFT, size = 8),
axis.ticks = element_blank(),
plot.title = element_text(color = INK, size = 12, hjust = 0.5),
plot.subtitle = element_text(color = INK_SOFT, size = 7.5, hjust = 0.5,
margin = margin(t = 4, b = 4)),
legend.position = "bottom",
legend.background = element_rect(fill = ELEVATED_BG, color = NA),
legend.text = element_text(color = INK_SOFT, size = 9),
legend.title = element_blank()
)
# --- Save -------------------------------------------------------------------
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/radar-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": "radar-basic",
"language": "r",
"library": "ggplot2",
"page": "https://anyplot.ai/radar-basic/r/ggplot2",
"hub": "https://anyplot.ai/radar-basic",
"code_json": "https://api.anyplot.ai/specs/radar-basic/ggplot2/code",
"spec_json": "https://api.anyplot.ai/specs/radar-basic",
"render_light_png": "https://storage.googleapis.com/anyplot-images/plots/radar-basic/r/ggplot2/plot-light.png",
"render_dark_png": "https://storage.googleapis.com/anyplot-images/plots/radar-basic/r/ggplot2/plot-dark.png",
"quality_score": 78.0,
"license": "MIT",
"guide": "https://anyplot.ai/llms.txt"
}Part of Basic Radar Chart on anyplot.ai.