I want to accentuate the area in the faceted density plots above the measure threshold of 2 (e.g., red shading for x=>2). This solution works well for a single facet factor, but I have two factors. How do I specify the levels for the two factors when using ggplot_build? Or do I need to use a different approach?
Here's a bit of the dataframe (the dataframe is 750 rows):
mode.f task.f mgds
1 1 A 1.1413636
2 1 A 0.9105000
3 2 A 1.0320000
4 2 A 1.1811429
14 1 C 1.4646000
15 1 C 1.7505000
16 2 C 1.3968000
17 1 D 1.0668333
18 1 D 1.0084000
19 1 D 1.1622500
20 2 D 1.3452500
21 2 D 1.0132000
22 3 C 0.6960000
23 3 C 0.9180000
24 3 D 1.0128000
25 3 D 0.6670000
26 2 E 2.9190000
27 2 E 1.3755000
28 2 E 1.4080000
29 1 E 1.3878000
30 1 E 1.4816667
Here's the code that works for a single facet factor:
mp <- ggplot(df,aes(x=mgds))+
geom_density(color=NA,fill="gray30",alpha=.4)+
facet_wrap(~mode.f)+
theme_bw()+
theme(strip.background =
element_rect(fill="gray95",color="gray60"),
strip.text = element_text(colour="black",size=10),
panel.border = element_rect(color="gray60"))+
labs(x="MGD (s)",y="Density")
to_fill <- data_frame(
x = ggplot_build(mp)$data[[1]]$x,
y = ggplot_build(mp)$data[[1]]$y,
mode.f = factor(ggplot_build(mp)$data[[1]]$PANEL, levels =
c(1,2,3), labels = c("1","2","3")))
mp + geom_area(data = to_fill[to_fill$x >= 2, ],
aes(x=x, y=y), fill = "red")
Here's the code for the facet_grid plots that I want to have the area beyond the x=2 threshold be a different color 2
ggplot(df,aes(x=mgds))+
geom_density(color=NA,fill="gray30",alpha=.4)+
facet_grid(~mode.f~task.f)+
theme_bw()+
theme(strip.background = element_rect(fill="gray95",color="gray60"),
strip.text = element_text(colour="black",size=10),
panel.border = element_rect(color="gray60"))+
geom_vline(xintercept=2,linetype="longdash",color="gray50")+
labs(x="Measure",y="Density")
