用tmap程序包绘制带指北针、图例和经纬网的采样点地图 

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setwd("C:/Users/jlzhang/Desktop/sample_map")
#### 导入所需要的程序包
library(rgdal)
library(tmap)
library(tmaptools)
library(sp)
rm(list = ls())
## 读取地图
country <- readOGR("bou1_4l.shp")
province <- readOGR("province_polygon.shp")
world <- readOGR("ne_50m_admin_0_countries.shp")
# Source: https://www.naturalearthdata.com/downloads/50m-cultural-vectors/ 
world <- set_projection(world, "longlat")    
country <- set_projection(country, "longlat")    
province <- set_projection(province, "longlat")    
province <- set_projection(province, "longlat")    
data(World)
# 城市
city <- read.csv("simplemaps-worldcities-basic.csv", header = TRUE)
city <- city[sample(1:nrow(city), 400),] # 随机筛选400个
coordinates(city) <- ~lng+lat 
proj4string(city) <- CRS("+proj=longlat +datum=WGS84")

World$name[World$name == "Taiwan"] <- NA
# 转换为spatial dataframe
# 绘图
tm_shape(world, 
         xlim = c(60, 140), 
         ylim = c(0, 60)) + 
  tm_borders("grey40", lwd = 1.5) + 
  tm_grid()+ 
tm_shape(province) +
  tm_fill(col = "lightgrey") + 
  tm_borders("grey60", lwd = 0.8) + 
tm_shape(country) + 
  tm_lines(col="grey40", lwd = 1.5) + 
tm_scale_bar(position=c(0.05,0.0)) + 
tm_compass(type = "4star", 
           position=c("left", "top")) +     
tm_layout(inner.margins=c(0.12,0.03,0.08,0.03), 
          legend.stack = "horizontal") + 
tm_shape(city) +
    tm_bubbles("pop", 
               col = "red", 
               scale=.5,
               border.col = "red") + 
    tm_text("city", size=0.5) + 
tm_legend(legend.position = c(0.05, 0.08)) + 
tm_shape(World) +
    tm_text("name", size=1.0)