Two Y axes (same scale) in ggplot2 or plot
On 08/05/2012 3:23 PM, Gary Dong wrote:
Dear R users, I'm plotting housing prices in City A over past 30 years in ggplot2. The Xs are years since 1980. I have two housing price variables: new home prices and old home prices, both of them measured by $/sqft. I have searched related threads on multiple Y axes in ggplot2 and I understand that multiple Y axes in different scales are not possible. I'm wondering if it is possible to have multiple Y axes with the same scale in ggplot2, like in my case. If still not possible, is there a easy way to do it in R's default plot function? Thanks.
In base graphics, you can have as many axes as you like, displaying anything. Use the axis() function. See ?axis for the arguments that determine placement, ticks, etc. I would guess the same flexibility is there in ggplot2, but I don't know how to do it. Duncan Murdoch