katydid_scatterplot.R

# download file from here: https://www.dragoart.com/tuts/10861/2/1/86731/how-to-draw-a-conehead-katydid,-conehead-katydid-step-9.htm

# right click on the black and white drawing, and "save as" to a folder, it should save as a JPEG

library(raster)
library(tidyverse)

# make a raster from your downloaded image
test_raster <- raster("../../Downloads/katydid.jpg")

# extract the coordinates with a low value (black lines from the original drawing)
coords <- coordinates(test_raster)[values(test_raster) < 200,]

# turn it into a data.frame, but only use every 20th value (can tweak depending on how sparse you want the scatter)
coords_df <- as.data.frame(coords)[c(rep(FALSE,19), TRUE),]

# there's a weird chunk at the bottom of the image, so I'm just cutting it off by taking only y values that are above it
coords_df <- coords_df[coords_df$y > 45,]

# plot with some jitter to look more scatter-y. Probably wanna tweak this a bit depending on how you want it to look.
ggplot(coords_df, aes(x = x, y = y))+
  geom_jitter(width = 5, height = 5)+
  theme_bw()

# if you want to plot in base and still get the "scattery" look, I think you could just add some noise to every X and Y coordinate in coords_df