How to incorporate data into plot which was constructed in ggplot2 using data from another file (R)?

Question

Using a dataset, I have created the following plot:

I'm trying to create the following plot:

Specifically, I am trying to incorporate Twitter names over the first image. To do this, I have a dataset with each name in and a value that corresponds to a point on the axes. A snippet looks something like:

Name             Score
@tedcruz         0.108
@RealBenCarson   0.119

Does anyone know how I can plot this data (from one CSV file) over my original graph (which is constructed from data in a different CSV file)? The reason that I am confused is because in ggplot2, you specify the data you want to use at the start, so I am not sure how to incorporate other data.

Thank you.

Answer 1

The question you ask about ggplot combining source of data to plot different element is answered in this post here

Now, I don't know for sure how this is going to apply to your specific data. Here I want to show you an example that might help you to go forward.

Imagine we have two data.frames (see bellow) and we want to obtain a plot similar to the one you presented.

data1 <- data.frame(list(
  x=seq(-4, 4, 0.1), 
  y=dnorm(x = seq(-4, 4, 0.1))))
data2 <- data.frame(list(
  "name"=c("name1", "name2"), 
  "Score" = c(-1, 1)))

The first step is to find the "y" coordinates of the names in the second data.frame (data2). To do this I added a y column to data2. y is defined here as a range of points from the may value of y to the min value of y with some space for aesthetics.

range_y = max(data1$y) - min(data1$y)
space_y = range_y * 0.05
data2$y <- seq(from = max(data1$y)-space, to = min(data1$y)+space, length.out = nrow(data2))

Then we can use ggplot() to plot data1 and data2 following some plot designs. For the current example I did this:

library(ggplot2)
p <- ggplot(data=data1, aes(x=x, y=y)) + 
  geom_point() + # for the data1 just plot the points
  geom_pointrange(data=data2, aes(x=Score, y=y, xmin=Score-0.5, xmax=Score+0.5)) +
  geom_text(data = data2, aes(x = Score, y = y+(range_y*0.05), label=name))
p 

which gave this following plot: