1.The shape palette can deal with a maximum of 6 discrete values because more than 6 becomes difficult to discriminate;.....
解決方法:http://www.sthda.com/english/wiki/ggplot2-point-shapes
總結:ggplot2默認支持六種不同點形,若要增加,如需要七種不同的的點型:
ggplot(data,aes(x=time,y=value))+
geom_point(aes(shape=school),size=0.8)+
geom_line()+
scale_shape_manual(values=c(1,2,4,5,7,8,13))
數字——點型對應如下: