Reusing axes ranges from previous ggplot facet

I'm trying to figure out a way to use the axes ranges from a facet_wrap object I created with just the data when I add glm fits, which are poor and greatly expand the axes ranges.

Here's an example


data <-  structure(list(ID = structure(c(14L, 14L, 14L, 14L, 14L, 13L, 
13L, 13L, 13L, 13L), levels = c("T229", "T230", "T231", "T234", 
"T235", "T236", "T237", "T243", "T244", "T246", "T247", "T257", 
"T258", "T259", "T260"), class = "factor"), x = c(35, 40, 42, 
44, 27, 35, 40, 27, 42, 44), y = c(7, 0, 0, 0, 18, 74, 45, 20, 
32, 0)), row.names = c(NA, -10L), class = "data.frame")

## Data only Plot

xlab <- "X Label"
ylab <- "Y Label"

plot_data_only <-
    ggplot(data)   
    aes(x = x,
        y = y)  
    facet_wrap("ID", scales = "free_y")  
    geom_jitter()  
    labs(x = xlab, y = ylab,
         title = "Just the Data") 

## Plot data and model


plot_data_only  
    stat_smooth(method = "glm",
                method.args = list(
                    family = quasipoisson(link = "log"),
                    start = coefficients(glm_combined),
                    maxit = 100),
                se = FALSE,
                formula = y ~ 1   x   I(x^2), size = 1,
                )  
         labs(title = "Data and model fits-- oh my")

Here's what I get:

Instead of the second plot going from 0 to 16 in the second panel, it goes from 0 to 4500!

I've tried using something like plot_data_only$scales , but clearly I don't understand ggplot2 very well.

Is there an object I can extract from the original plot and reuse in the second one?

CodePudding user response：

It is actually possible to copy over the exact panel parameters so that you have the same axis limits in your second plot, though it's a bit hacky:

plot_with_smooth <- plot_data_only  
  stat_smooth(method = "glm", aes(group = ID),
              method.args = list(
                family = quasipoisson(link = "log"),
                maxit = 1000),
              se = FALSE,
              formula = y ~ 1   x   I(x^2), size = 1,
  )  
  labs(title = "Data and model fits-- oh my") 

p1 <- ggplot_build(plot_data_only)
p2 <- ggplot_build(plot_with_smooth)

p2$layout$panel_scales_y[[2]] <- p1$layout$panel_scales_y[[2]]
p2$layout$panel_params <- p1$layout$panel_params

grid::grid.draw(ggplot_gtable(p2))

CodePudding user response：

You can set yaxis limits by adding ylim() to your ggplot like this:

plot_data_only  
    stat_smooth(method = "glm",
                method.args = list(
                    family = quasipoisson(link = "log"),
                    start = coefficients(glm_combined),
                    maxit = 100),
                se = FALSE,
                formula = y ~ 1   x   I(x^2), size = 1)  
    labs(title = "Data and model fits-- oh my") 
    ylim(0,20)

Thought using this method on facet_wrap leads to the yaxis scaled looking the same on both panels. If you want to set two different scales then you might want to refer to this previously asked question and decide what would be best for you.