qplot(length, rating, data = movies, geom = "blank")
# Nothing to see here!
# Take the following scatter plot
a <- ggplot(mtcars, aes(x = wt, y = mpg), . ~ cyl) + geom_point()
# Add to that some lines with geom_abline()
df <- data.frame(a = rnorm(10, 25), b = rnorm(10, 0))
a + geom_abline(aes(intercept = a, slope = b), data = df)
# Suppose you then wanted to remove the geom_point layer
# If you just remove geom_point, you will get an error
b <- ggplot(mtcars, aes(x = wt, y = mpg), . ~ cyl)
b + geom_abline(aes(intercept = a, slope = b), data = df)
# Switching to geom_blank() gets the desired plot
c <- ggplot(mtcars, aes(x = wt, y = mpg), . ~ cyl) + geom_blank()
c + geom_abline(aes(intercept = a, slope = b), data = df)
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