I'd like to manually adjust appearance of several manhattan plots generated using ggplot2 and combine them into one nice figure for our paper. The problem is when I try to handle the PDF plots with vector graphics editors, all operations take so much time it is impossible to make any changes in the plots.
Is there any way to simplify the plots so that they can be more easily edited in AI (e.g., merge points from each chromosome into one shape, or sth else)? How do people usually handle manhattan plots during figure editing?
Many thanks for your help :)