处理用ggplot2绘制的弦线图中的异常值

I want to do some plotting of map data in ggplot where the polygons are filled according to values of a continuous variable. One problem I have is that there are just a handful of extreme outliers (~10 out of 3000) in the data that prevent most of the other observations from being displayed with enough meaningful color variation. I want to do some plotting of map data in ggplo