geom_mapcn: Plot China Map with Customizable Options

In ggmapcn: Customizable China Map Visualizations

Plot China Map with Customizable Options

Description

‘geom_mapcn' provides a flexible interface for visualizing China’s administrative boundaries. Users can select administrative levels (province, city, or county), apply custom projections, and filter specific regions.

Usage

geom_mapcn(
  data = NULL,
  admin_level = "province",
  crs = "+proj=aeqd +lat_0=35 +lon_0=105 +ellps=WGS84 +units=m +no_defs",
  color = "black",
  fill = "white",
  linewidth = 0.5,
  filter_attribute = NULL,
  filter = NULL,
  ...
)

Arguments

data	An ‘sf' object containing China’s map data. If ‘NULL', the function loads the package’s default map. Users can select provincial, municipal, or county-level maps using the 'admin_level' parameter.
admin_level	A character string specifying the administrative level of the map. Options are '"province"' (default), '"city"', or '"county"'. The corresponding '.rda' files (‘China_sheng.rda', 'China_shi.rda', 'China_xian.rda') must be located in the package’s 'extdata' folder.
crs	A string specifying the Coordinate Reference System (CRS). Defaults to '"+proj=aeqd +lat_0=35 +lon_0=105 +ellps=WGS84 +units=m +no_defs"'. Users can specify other CRS strings (e.g., '"EPSG:4326"').
color	Border color. Default is '"black"'.
fill	Fill color. Default is '"white"'.
linewidth	Line width for borders. Default is '0.5'. Note: 'linewidth' is used to control the border width in 'ggplot2' version 3.3.0 or higher. Use 'size' for earlier versions.
filter_attribute	Column name for filtering regions (e.g., '"name_en"').
filter	A character vector of values to filter specific regions (e.g., 'c("Beijing", "Shanghai")').
...	Additional parameters passed to 'geom_sf'.

Value

A ‘ggplot2' layer (of class 'ggproto') for visualizing China’s administrative boundaries. This layer can be added to a 'ggplot' object to generate maps with customizable projections, border colors, fill colors, and more.

Examples

# Plot provincial map (default)
ggplot() +
  geom_mapcn() +
  theme_minimal()

# Filter specific provinces
ggplot() +
  geom_mapcn(filter_attribute = "name_en", filter = c("Beijing", "Shanghai"), fill = "red") +
  theme_minimal()

# Use a Mercator projection
ggplot() +
  geom_mapcn(crs = "+proj=merc", linewidth = 0.7) +
  theme_minimal()

ggmapcn documentation built on April 12, 2025, 2:09 a.m.