Multiple line and bar chart in ggplot with geom_text and colours - r

Question

I want to combine a line and a bar chart with three different variables using ggplot. The bar chart should have the values on top and should be filled with the same colours as the lines in the chart above. Here is my code
# First some data generation
df.x = data.frame(date = Sys.Date()-20:1,
value = c(1:20),
variable = "line",
object = "x")
df.y = data.frame(date = Sys.Date()-20:1,
value = c(1:20)*2,
variable = "line",
object = "y")
df.z = data.frame(date = Sys.Date()-20:1,
value = c(1:20)*3,
variable = "line",
object = "z")
df.y.bar = data.frame(date = Sys.Date()-10,
value = 30,
variable = "bar",
object = "y")
df.x.bar = data.frame(date = Sys.Date()-10,
value = 40,
variable = "bar",
object = "x")
df.z.bar = data.frame(date = Sys.Date()-10,
value = 50,
variable = "bar",
object = "z")
df = rbind(df.x, df.y,df.z, df.x.bar, df.y.bar,df.z.bar)
my.cols = c("blue", "green", "yellow")
# Pass everything to ggplot
ggplot(df, aes_string(x = "date", y = "value", fill="variable")) +
facet_grid(variable~., scales="free_y") +
geom_line(data = subset(df, variable == "line"), aes(colour = factor(object)), size = 1, show_guide = FALSE, stat="identity") +
geom_bar(data = subset(df, variable == "bar"), aes(colour = factor(object)), show_guide = TRUE, stat="identity", position = "dodge") +
geom_text(data = subset(df, variable == "bar"), aes(y=value+0.7 * sign(value), ymax=value, label=round(value, 2)), position = position_dodge(width = 0.9), size=3) +
scale_colour_manual(values = my.cols)
The resulting plot is not exactly what I wanted. I used position_dodge(width = 0.9) but the text over the bars does not move. Irretatingly this does not happen when I only chose two variable (e.g. x and y) to be included in the data frame. The desired result should look like this:
Thanks a lot for your help!

Answer 1

You can fill the bars by choosing fill = factor(object) and adding scale_fill_manual(values = my.cols).
In order to have only one legend I think removing fill="variable" from aes_string did the trick in combination with scale_fill_manual.
And for dodging the text you need to add a group argument and position = position_dodge(width=1)
ggplot(df, aes_string(x = "date", y = "value")) +
facet_grid(variable~., scales="free_y") +
geom_line(data = subset(df, variable == "line"), aes(colour = factor(object)), size = 1, show_guide = FALSE, stat="identity") +
geom_bar(data = subset(df, variable == "bar"), aes(fill = factor(object)), show_guide = TRUE, stat="identity", position = "dodge") +
geom_text(data =subset(df, variable == "bar"), aes(x=date, y=(value+0.7) * sign(value), ymax=value, label=round(value, 2), group=object), position = position_dodge(width=1), size=3) +
scale_colour_manual(values = my.cols) +
scale_fill_manual(values = my.cols)