如何制作带有指示流动方向的箭头、不同粗细的线条以及 A 到 B 和 B 到 A 流动不重叠的流程图

是的，可以使用ggplot2( tidyverse) 和 sf。的curvature需要geom_curve()与 0 不同，例如。0.5，为了创建一个没有重叠箭头的椭圆，A--> B 和 B-->A。

这是一个快速尝试。您可能需要为 Alpha 和线宽创建容器。

library(sf)
library(tidyverse)

# Shapefile of US in a almost random CRS, downloaded from 
# https://www2.census.gov/geo/tiger/GENZ2018/shp/cb_2018_us_state_20m.zip
us_shp = st_read( "cb_2018_us_state_20m/cb_2018_us_state_20m.shp") %>% 
  st_transform("ESRI:102003")

# State center (arrow start and end), from datasets::
state_center = state.center %>% as_tibble() %>% st_as_sf(coords=c("x","y") ,
                                                         crs = 4326, remove=FALSE)%>% 
  st_transform("ESRI:102003") %>% 
  mutate(state_id = 1:n()) %>% 
  dplyr::mutate(x = sf::st_coordinates(.)[,1],
                y = sf::st_coordinates(.)[,2])

# Creation of a 50*50 dataframe, but we will select some states only at the end
state_exchange =    expand.grid(state1= 1:50, state2 = 1:50 ) %>% 
  mutate( values = rnorm(50*50)) %>% 
  as_tibble() %>% 
  filter(state1!=state2) %>% 
  filter( state1 <4, state2<4)

# Adding start-end 
state_exchange_sf =  state_exchange %>% 
  left_join( state_center %>% st_drop_geometry(), 
             by = c("state1" = "state_id"),
             suffix= c("","start") ) %>% 
  left_join( state_center %>% st_drop_geometry(), 
             by = c("state2" = "state_id"),
             suffix= c("","end"))

ggplot()+geom_sf(data= us_shp)+
  geom_sf(data=state_center)+
  geom_curve( data =state_exchange_sf %>%
                st_as_sf(coords= c("x","y"), crs= "ESRI:102003", remove=FALSE),
              aes(x= x, y= y, xend= xend, yend=yend,
                  alpha= values , linewidth = values), 
              curvature = -0.5 , arrow= grid::arrow()  )