Plot Boundaries of China

Draws various types of boundaries for China, including mainland boundaries, coastlines, ten-segment line, special administrative region (SAR) boundaries, and undefined boundaries. Each boundary type can be customized in terms of color, line width, and line type. This function also allows optional addition of a compass and a scale bar.

Usage

geom_boundary_cn(
  crs = "+proj=aeqd +lat_0=35 +lon_0=105 +ellps=WGS84 +units=m +no_defs",
  compass = FALSE,
  scale = FALSE,
  mainland_color = "black",
  mainland_size = 0.5,
  mainland_linetype = "solid",
  coastline_color = "blue",
  coastline_size = 0.3,
  coastline_linetype = "solid",
  ten_segment_line_color = "black",
  ten_segment_line_size = 0.5,
  ten_segment_line_linetype = "solid",
  SAR_boundary_color = "grey",
  SAR_boundary_size = 0.5,
  SAR_boundary_linetype = "dashed",
  undefined_boundary_color = "black",
  undefined_boundary_size = 0.5,
  undefined_boundary_linetype = "longdash",
  ...
)

Arguments

crs

Character. Coordinate reference system (CRS) for the projection. Defaults to "+proj=aeqd +lat_0=35 +lon_0=105 +ellps=WGS84 +units=m +no_defs". Users can specify other CRS strings to customize the projection (e.g., "+proj=merc" for Mercator).

compass

Logical. Whether to display a compass (north arrow). Default is FALSE. If set to TRUE, a default compass (north arrow) with ggspatial::north_arrow_fancy_orienteering() will be added to the top-left corner. To customize the compass, use ggspatial::annotation_north_arrow() directly.

scale

Logical. Whether to display a scale bar. Default is FALSE. If set to TRUE, a default scale bar with ggspatial::annotation_scale() will be added to the bottom-left corner. To customize the scale bar, use ggspatial::annotation_scale() directly.

mainland_color

Character. Color for the mainland boundary. Default is "black".

mainland_size

Numeric. Line width for the mainland boundary. Default is 0.5.

mainland_linetype

Character. Line type for the mainland boundary. Default is "solid".

coastline_color

Character. Color for the coastline. Default is "blue".

coastline_size

Numeric. Line width for the coastline. Default is 0.3.

coastline_linetype

Character. Line type for the coastline. Default is "solid".

ten_segment_line_color

Character. Color for the ten-segment line. Default is "black".

ten_segment_line_size

Numeric. Line width for the ten-segment line. Default is 0.5.

ten_segment_line_linetype

Character. Line type for the ten-segment line. Default is "solid".

SAR_boundary_color

Character. Color for the SAR boundary. Default is "grey".

SAR_boundary_size

Numeric. Line width for the SAR boundary. Default is 0.5.

SAR_boundary_linetype

Character. Line type for the SAR boundary. Default is "dashed".

undefined_boundary_color

Character. Color for the undefined boundary. Default is "lightgrey".

undefined_boundary_size

Numeric. Line width for the undefined boundary. Default is 0.5.

undefined_boundary_linetype

Character. Line type for the undefined boundary. Default is "longdash".

...

Additional parameters passed to geom_sf.

Value

A ggplot2 layer (or list of layers) displaying China's multi-segment boundaries with the specified styles, optionally including a compass (north arrow) and a scale bar.

Examples

if (FALSE) { # \dontrun{
# Plot China's boundaries with default settings
ggplot() +
  geom_boundary_cn() +
  theme_minimal()

# Plot China's boundaries with a compass and scale bar
ggplot() +
  geom_boundary_cn(compass = TRUE, scale = TRUE) +
  theme_minimal()

# For customized compass or scale bar, use ggspatial directly:
ggplot() +
  geom_boundary_cn() +
  ggspatial::annotation_north_arrow(
    location = "br", style = ggspatial::north_arrow_minimal()
  ) +
  ggspatial::annotation_scale(
    location = "tr", width_hint = 0.3
  ) +
  theme_minimal()
} # }