I am looking to count the number of points in a certain region of my scatter plot with ggplot2-CodePudding

I have a scatter plot:

ex<- ggplot(rdr, aes(x = hb, y = iv, color = pt))  geom_point()   
  ylim(-20,20)   
  xlim(-20,20)  
  annotate(geom = "rect", xmin = -10, xmax = 10, ymin = -10, ymax = 10,
           fill = "gray100", colour = "black", alpha = 0.5)   
  annotate( geom = "rect", xmin = -10, xmax = 10, ymin = -15, ymax = -10, fill = "palegreen", color = "blue", alpha =0.5)

I want to count how many points are in each of the rectangles. And depending on the color of the point, I want to give them values. ex: blue(0), green(1).

How can I do this?

CodePudding user response：

If you know the range for each variable in advance (which it seems like you do based on the xmin / ymin args you have), then I would do annotation first.

You don't have a scatterplot, you have data you are representing as a scatterplot, and you want to annotate the points so that they display as different colors on the scatterplot.

library(dplyr)
library(ggplot2)
data(mtcars)
mtcars2 = mtcars %>%
  mutate(good = case_when(
    # this is the annotation step
    between(hp, 100, 150) & between(mpg, 15, 20) ~ 1,
    # this says everything else gets this value
    TRUE ~ 0
))
# we need as.factor to get different colors displayed
ggplot(mtcars2, aes(x = mpg, y = hp, color = as.factor(good)))   geom_point()