如何用ggplot2将流式细胞术数据绘制成地铁图样式？

我想用ggplot2将流式细胞术（Flow Cytometry）数据绘制成类似下图的地铁图样式：

我可以提供包含清晰节点的完整路径可复现数据：

fullPopulationPaths = 
 c("root",                                                                                                                            
   "/Single Cells",                                                                                                                   
   "/Single Cells/Live",                                                                                                              
   "/Single Cells/Live/CD45 int CD123+",                                                                                              
   "/Single Cells/Live/CD45 int CD123+/CD45 int CD123+ DR-CD38+ Basophils",                                                           
   "/Single Cells/Live/CD45+",                                                                                                        
   "/Single Cells/Live/CD45+/Lymphocytes",                                                                                            
   "/Single Cells/Live/CD45+/Lymphocytes/CD3+ TCR+",                                                                                  
   "/Single Cells/Live/CD45+/Lymphocytes/CD3+ TCR+/CCR7+TCRgd+",                                                                       
   "/Single Cells/Live/CD45+/Lymphocytes/CD3+ TCR+/CCR7-",                                                                             
   "/Single Cells/Live/CD45+/Lymphocytes/CD3+ TCR+/CCR7-CD45RA++TCRgd+",                                                              
   "/Single Cells/Live/CD45+/Lymphocytes/CD3+ TCR-",                                                                                  
   "/Single Cells/Live/CD45+/Lymphocytes/CD3+ TCR-/CD3+ CD56-" ,                                                                      
   "/Single Cells/Live/CD45+/Lymphocytes/CD3+ TCR-/CD3+ CD56-/CD4+",                                                                  
   "/Single Cells/Live/CD45+/Lymphocytes/CD3+ TCR-/CD3+ CD56-/CD4+/CD4+CD45RA++CCR7+"   ,                                             
   "/Single Cells/Live/CD45+/Lymphocytes/CD3+ TCR-/CD3+ CD56-/CD4+/CD4+CD45RA++CCR7+/naive CD4+" ,                                    
   "/Single Cells/Live/CD45+/Lymphocytes/CD3+ TCR-/CD3+ CD56-/CD4+/CD4+CD45RA-CCR7+")

我尝试了Stack Overflow帖子《how to create a subway map visualisation of my data》中的代码，但该代码对我的数据无效。

内容的提问来源于stack exchange，提问作者Agustina Conrrero