r - How to draw a contour plot when data are not on a regular grid?

Question

Say I have 3 variables such that

x=1:9
y=c(1,1,1,2,2,2,3,3,3)
z=6:14

How can I rearrange the data so that I can make a contour plot of the data with r? I am getting the message

Error in contour.default(x, y, z) : 
  increasing 'x' and 'y' values expected

Thank you.

Answer 1

z是matrix要绘制等高线的值。x并且y是它们各自的位置。r-help 邮件列表中的“Tyler”对此进行了解释，并举例说明了如何转换数据以使事情正常进行。另请参阅帮助中的示例?contour。

x = seq(0, 10, by = 0.5)
y = seq(0, 10, by = 0.5)
z <- outer(x, y)

contour(x, y, z)