R语言ggplot2包绘制世界地图

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1. 数据读取与处理

首先，从CSV文件中读取数据，并计算各国每日收入的平均签证成本。

library(tidyverse)

df <- read_csv("df.csv") %>% group_by(source, source_iso3) %>% summarise(avg_work=mean(work_perdailyincome, na.rm=TRUE)) %>% mutate_all(~ifelse(is.nan(.), NA, .))

2. 数据合并

将处理后的数据与世界地图数据进行合并，以便在地图上进行可视化。

library(rnaturalearth)
library(sf)

world <- ne_countries(scale = "medium", returnclass = "sf") %>% select(iso_a3,geometry)

df2 <- left_join(world,df,by=c("iso_a3"="source_iso3")
)

3. 可视化设置

使用 ggplot2 和 scico 包进行地图绘制，采用自定义主题和配色方案，确保地图清晰、美观。

library(showtext)
library(scico)
library(rnaturalearthdata)

showtext_auto(enable = TRUE)
font <- "Fira Sans Condensed"
font_add_google(family=font, font)
theme_set(theme_minimal(base_family = font))
bg <- "#1F1D36"
txt_col <- "grey95"

4. 绘制初步地图

根据处理后的数据生成初步地图，展示全球各国工作签证的平均成本。

df2 %>% ggplot() +geom_sf(aes(fill=avg_work, geometry=geometry), color="grey20", size=.1) +scale_fill_scico(palette = "imola",direction = 1,na.value="grey95",limits=c(0,180),breaks=seq(0,180,45),begin=.5,end=1)

ggsave("pic1.png", width = 7, height = 4)

5. 美化地图

进一步美化地图，使其更具吸引力和可读性。

df2 %>% ggplot() +geom_sf(aes(fill=avg_work, geometry=geometry), color="grey20", size=.1) +scale_fill_scico(palette = "imola",direction = 1,na.value="grey95",limits=c(0,180),breaks=seq(0,180,45),begin=.5,end=1) +coord_sf(crs = "+proj=merc", ylim = c(-7000000,11000000)) +theme(panel.grid = element_blank(),axis.title = element_blank(),axis.text = element_blank(),plot.margin = margin(30,30,30,30),plot.background = element_rect(color=bg, fill=bg),plot.title = element_text(hjust=0,size=18, color=txt_col,lineheight=.8, face="bold", margin=margin(0,0,0,0)),plot.subtitle = element_text(hjust=0,size=12, color=txt_col,lineheight=.8, margin=margin(10,0,20,0)),plot.caption = element_text(hjust=.5,margin=margin(10,0,0,0), size=8, color=txt_col, face="bold"),legend.position = "bottom",legend.title = element_text(size=7, color=txt_col),legend.text = element_text(size=6, color=txt_col))  +guides(fill = guide_colourbar(ticks.colour = NA,title.position="top",title.hjust = 0.5,barwidth = unit(6, "cm"),barheight = unit(.4,"cm"),))

ggsave("pic2.png", width = 7, height = 4)