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Plot World Map with Customizable Options

Source: R/geom_world.R
geom_world.Rd

geom_world is a wrapper around ggplot2::geom_sf() designed for visualizing world maps with added flexibility. It allows custom projections, filtering specific countries or regions, and detailed aesthetic customizations for borders and fills.

Usage

geom_world(
  data = NULL,
  crs = "+proj=longlat +datum=WGS84",
  color = "black",
  fill = "white",
  linewidth = 0.5,
  filter_attribute = "SOC",
  filter = NULL,
  ...
)

Arguments

data

An sf object containing world map data. If NULL, the function loads the package's default world.geojson dataset.

crs

A character string. The target coordinate reference system (CRS) for the map projection. Defaults to "+proj=longlat +datum=WGS84".

color

A character string specifying the border color for administrative boundaries. Default is "black".

fill

A character string specifying the fill color for administrative areas. Default is "white".

linewidth

A numeric value specifying the line width for administrative boundaries. Default is 0.5.

filter_attribute

A character string specifying the column name to use for filtering countries or regions. Default is "SOC", which refers to the ISO 3166-1 alpha-3 country code in the default dataset.

filter

A character vector specifying the values to filter specific countries or regions. Default is NULL.

...

Additional parameters passed to ggplot2::geom_sf(), such as size, alpha, or lty.

Value

A ggplot2 layer for world map visualization.

Details

geom_world simplifies the process of creating world maps by combining the functionality of geom_sf with user-friendly options for projections, filtering, and custom styling. Key features include:

  • Custom projections: Easily apply any CRS to the map.

  • Filtering by attributes: Quickly focus on specific countries or regions.

  • Flexible aesthetics: Customize fill, borders, transparency, and other visual properties.

See also

ggplot2::geom_sf(), sf::st_transform(), sf::st_read()

Examples

  # Plot the default world map
  ggplot() +
    geom_world() +
    theme_minimal()


  # Apply Mercator projection
  ggplot() +
    geom_world(crs = "+proj=merc") +
    theme_minimal()


  # Filter specific countries (e.g., China and its neighbors)
  china_neighbors <- c("CHN", "AFG", "BTN", "MMR", "LAO", "NPL", "PRK", "KOR",
                       "KAZ", "KGZ", "MNG", "IND", "BGD", "TJK", "PAK", "LKA", "VNM")
  ggplot() +
    geom_world(filter = china_neighbors) +
    theme_minimal()


  # Background map + Highlight specific region
  ggplot() +
    geom_world(fill = "gray80", color = "gray50", alpha = 0.5) +
    geom_world(filter = c("CHN"), fill = "red", color = "black", linewidth = 1.5) +
    theme_minimal()


  # Customize styles with transparency and bold borders
  ggplot() +
    geom_world(fill = "lightblue", color = "darkblue", linewidth = 1, alpha = 0.8) +
    theme_void()