数据集

library(dplyr)
library(ggplot2)

autompg = read.table("http://archive.ics.uci.edu/ml/machine-learning-databases/auto-mpg/auto-mpg.data",quote = "\"",comment.char = "",stringsAsFactors = FALSE)

head(autompg,20)

colnames(autompg) = c("mpg", "cyl", "disp", "hp", "wt", "acc", "year", "origin", "name")

autompg$hp = as.numeric(autompg$hp)

autompg = autompg %>% mutate(origin = ifelse(origin>1,'local','international models'))
head(autompg, 20)

现在，我必须完成下面的代码段，以创建一个散点图的mpg与。通过根据原点（本地或国际）对点进行颜色编码来进行位移。为打印添加轴标签和标题。
我的解决方案显示错误：

p = ggplot(data = autompg, 
           aes(x = mpg, y = displacement, color = origin)) + 
      geom_point(mapping = aes(x = mpg, y = displacement, 
                               color = origin)) + 
      labs(x = 'mpg (km/hr)', y = 'displacement (km)', title = 'mpg vs. displacement')

我哪里做错了？