Digitizing jpeg graphs in R

February 12, 2014
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(This article was first published on R by Emmanuel Jjunju, and kindly contributed to R-bloggers)

I have been using third party programs for a long time until i came across the documentation for the R-package digitize. unfortunately, this package is not available for R 3.0.2 so i had to tweek things around. I am glad to share my solution.

I started by taking a look at http://lukemiller.org/index.php/2011/06/digitizing-data-from-old-plots-using-digitize/. Luke Miller has written a very nice description of how to use the digitize package. Some of the text here presented is from Luke Miller.

The digitize package by Timothée Poisot actually relies mainly  only the  functions readImg, ReadAnadCal, Digitdata and Calibrate. ReadImg requires readJPEG from the jpeg package. Once the jpeg package is installed and loaded,  then just  load these functions  craeted by Timothée Poisot. The functions can be downloaded from https://github.com/tpoisot/digitize/blob/master/digitize/R/functions.r

The code snippet below shows my implementation. I have added the use of the tcltk2 package so that one can browse and select the the jpeg file directly.





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