ggplot中点的样式展示：

library(ggplot2)

# 创建数据框
a<- data.frame(x = 0:25, y = 0:25)
# 创建散点图
ggplot(a, aes(x = x, y = y, shape = as.factor(y))) +
  geom_point(size = 4) +
  scale_shape_manual(values = 0:25) +
  labs(shape = "形状") +
  theme(legend.direction = "vertical",
        legend.position = "bottom",
        legend.key = element_rect(colour = "white", fill = "white"))

示例图如下：