To extract data from a jpg file in R using the digitize package:
*.jpg
file
csv
file steps below
library('digitize') calpts <- ReadAndCal('authorYYYabc_fixX.jpg') ## click on xaxis min (x1), xaxis max (x2), ## yaxis min(y1), yaxis max (y2) pts <- DigitData(col='red',type='p',n=8) ## set n = to the number of points to collect data <- Calibrate(pts, calpts, x1, x2, y1, y2) ## x1, x2, y1, and y2 are the min and max of the x and y axes, respectively. print(data) write.csv(data, 'authorYYYYabc_figX.csv')