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Insper Area Plot

Source: R/plot-area.R
insper_area.Rd

Create area charts for time series data using Insper's visual identity. Supports both single and grouped/stacked areas.

Usage

insper_area(
  data,
  x,
  y,
  fill = NULL,
  palette = NULL,
  stacked = NULL,
  area_alpha = 0.9,
  fill_color = get_insper_colors("teals1"),
  add_line = TRUE,
  line_color = get_insper_colors("teals3"),
  line_width = 0.8,
  line_alpha = 1,
  zero = FALSE,
  ...
)

Arguments

data

A data frame containing the data to plot

x

Time variable (numeric, Date, or POSIXct)

y

Value variable

fill

Fill aesthetic. Can be:

  • A quoted color name/hex (e.g., `"teal"`, `"#00BFFF"`) for static color

  • A bare column name (e.g., `category`) for discrete grouping

  • A continuous variable (e.g., `intensity`) for gradient coloring

If `NULL` (default), uses Insper teal. When a variable is mapped, it applies to both area fill and line color (if `add_line = TRUE`).

palette

Character. Color palette name for variable mappings. Options: "categorical", "main", "bright", "reds", "teals", etc. If NULL (default), uses "categorical". Only applies to variable mappings.

stacked

Logical. If TRUE and fill is provided, creates stacked areas. If NULL (default), automatically detects: stacks when `fill` is a variable mapping, otherwise uses overlapping areas. Set explicitly to FALSE to force overlapping areas even with fill mappings

area_alpha

Numeric. Transparency of areas (0-1). Default is 0.9

fill_color

Character. Hex color code for area when not using fill aesthetic. Default is Insper teal. (Deprecated: use `fill = "color"` instead)

add_line

Logical. If TRUE, adds line on top of area. Default is TRUE

line_color

Character. Hex color code for line when not using fill aesthetic. Default is darker Insper teal. (Deprecated: use in combination with `fill = "color"`)

line_width

Numeric. Width of line. Default is 0.8

line_alpha

Numeric. Transparency of line (0-1). Default is 1

zero

Logical. If TRUE, adds a horizontal line at y = 0. Default is FALSE

...

Additional arguments passed to ggplot2::geom_area()

Value

A ggplot2 object

Details

## Smart Stacking Behavior

By default (`stacked = NULL`), the function automatically detects whether to stack areas based on context:

  • When `fill` is a variable (e.g., `fill = category`): automatically creates stacked areas to show part-to-whole relationships

  • When `fill` is missing or a static color: uses overlapping areas (stacking has no effect)

You can override this behavior by explicitly setting `stacked = TRUE` (force stacking) or `stacked = FALSE` (force overlapping, useful for comparing distributions of different groups).

## Line Overlay

By default, a line is drawn on top of each area (`add_line = TRUE`). This helps emphasize trends and makes the areas more visually distinct. The line color matches the fill color. Set `add_line = FALSE` for cleaner appearance when comparing many groups.

See also

theme_insper, scale_fill_insper_d, insper_timeseries

Other plots: insper_barplot(), insper_boxplot(), insper_density(), insper_heatmap(), insper_histogram(), insper_scatterplot(), insper_timeseries(), insper_violin()

Examples

if (FALSE) { # has_insper_fonts()
library(ggplot2)

# Simple area plot - Coal consumption since 1900
coal_data <- subset(fossil_fuel, fuel == "Coal" & year >= 1900)
insper_area(coal_data, x = year, y = consumption)

# Stacked area chart showing all fuels (automatically stacked when fill is provided)
recent_data <- subset(fossil_fuel, year >= 1950)
recent_data$fuel <- factor(recent_data$fuel, levels = c("Oil", "Gas", "Coal"))
insper_area(recent_data, x = year, y = consumption, fill = fuel) +
  labs(
    title = "Global Fossil Fuel Consumption",
    subtitle = "Primary energy consumption by fuel type (1950-present)",
    x = "Year",
    y = "Consumption (TWh)",
    fill = "Fuel Type"
  )

# Force overlapping areas (comparing distributions)
insper_area(recent_data, x = year, y = consumption,
            fill = fuel, stacked = FALSE) +
  labs(
    title = "Comparing Fuel Consumption Trends",
    subtitle = "Overlapping areas show individual trajectories",
    x = "Year",
    y = "Consumption (TWh)",
    fill = "Fuel Type"
  )
}