Scanned Graph by ScanIt

Scanned Graph by ScanIt


Today I ran into a real gem by accident as I was searching for images in Google. The image on the left here caught my eye and I decided to have a peek at the site where it came from.

It turned out to be a blog post on a case study for the program ScanIt where it was used to digitize a scanned graph from a textbook on heat transfer.


Now why was this interesting?

Well, for the following three reasons:

  1. translating graphs into tables is a tedious excercise,
  2. automated digitizing could increase accuracy dramatically and
  3. this software is FREE!

So what does ScanIt do?

ScanIt will take any graph in digital form (so jpeg,  gif or even a screen dump) and allows you to digitize the curves in that graph by taking three easy steps:

  1. mark the intersect of both axis and supply the coordinates of that point
  2. mark the end point of the axis in the same fashion
  3. mark any point of interest on the graph

ScanIt will then convert the pixel locations of your datapoints to the appropriate coordinates according to the graphs scale.  The resulting tabular data can then be exported as a text file so you can use it for lookups or data regression purposes.

However, it does not end there: you can click on a curve in the graph and it will scan it for you automatically! Also markers in a graph can be recognized and converted to their coordinates.

Finally the software allows you to fine tune each datapoint as you can shift the automatically scanned position per pixel using the arrow keys on your keyboard.

Licence conditions

This piece of software that could be worth 20-30 dollars easily as shareware comes absolutely free and can be re-distributed freely as long as it remains free and unaltered (so basically a GNU type licence).


You can download ScanIt on its website

have fun!


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