Example 1: Basic Map of China
To plot a map of China with province boundaries, use the
geom_mapcn() function. The map uses the Azimuthal Equal
@@ -80,7 +89,7 @@
The ggmapcn package provides various tools for visualizing geographic
+data in China and beyond. This vignette demonstrates the basic and
+advanced usage of geom_mapcn() and
+geom_world() for plotting administrative boundaries and
+combining geographic data.
To plot a map of China with province boundaries, use the
geom_mapcn() function. The map uses the Azimuthal Equal
@@ -80,7 +89,7 @@
Here’s a comprehensive example demonstrating how to plot province boundaries, buffer zones, and coastlines on the same map:
@@ -91,7 +100,79 @@
The geom_world() function allows you to visualize global
+data, while geom_mapcn() overlays China for detailed
+analysis.
+# Define projections
+china_proj <- "+proj=aeqd +lat_0=35 +lon_0=105 +ellps=WGS84 +units=m +no_defs"
+
+# Combine world map as a background and China map as overlay
+ggplot() +
+ # World map as background
+ geom_world(fill = "gray90", color = "gray70", linewidth = 0.2) +
+ coord_proj(
+ crs = "+proj=merc",
+ xlim = c(-180, 180),
+ ylim = c(-90, 90)
+ ) +
+ # Overlay China map
+ geom_mapcn(
+ fill = "lightblue",
+ color = "black",
+ linewidth = 0.5
+ ) +
+ geom_boundary_cn(color = "red", linewidth = 0.6) +
+ theme_minimal()
+#> Linking to GEOS 3.11.2, GDAL 3.8.2, PROJ 9.3.1; sf_use_s2() is TRUE
+#> Coordinate system already present. Adding new coordinate system, which will
+#> replace the existing one.
+#> Warning: Duplicated aesthetics after name standardisation: colour and linewidth
+#> Duplicated aesthetics after name standardisation: colour and linewidth
+#> Duplicated aesthetics after name standardisation: colour and linewidth
+#> Duplicated aesthetics after name standardisation: colour and linewidth
+#> Duplicated aesthetics after name standardisation: colour and linewidth
This example demonstrates filtering for China and its neighboring +countries, highlighting China in red.
+
+# Define neighboring countries
+china_neighbors <- c("CHN", "AFG", "BTN", "MMR", "LAO", "NPL", "PRK", "KOR",
+ "KAZ", "KGZ", "MNG", "IND", "BGD", "TJK", "PAK", "LKA", "VNM")
+
+# Plot world map with filtered countries
+ggplot() +
+ geom_world(fill = "gray90", color = "gray70", linewidth = 0.2) +
+ geom_world(
+ filter = china_neighbors,
+ filter_attribute = "SOC",
+ fill = "lightblue",
+ color = "black",
+ linewidth = 0.5
+ ) +
+ geom_world(
+ filter = "CHN",
+ filter_attribute = "SOC",
+ fill = "red",
+ color = "black",
+ linewidth = 0.8
+ ) +
+ coord_proj(
+ crs = "+proj=merc",
+ xlim = c(60, 140),
+ ylim = c(-10, 60)
+ ) +
+ theme_minimal()