An app for easily digitizing data points from X-Y graphs
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Image Digitizer

A MATLAB GUI tool for extracting data points from 2D X-Y graphs.

System requirements

To run from MATLAB: any operating system with MATLAB (version R2014a or newer) installed can run this app. It also works on the remote end of a Linux server that has MATLAB installed (you need to have X11 enabled when you access the server).

To run without MATLAB: Windows or Mac.

Features and limitations

The features of this GUI app are a subset of another free app called Engauge Digitizer. But this GUI app is faster to oparate (fewer mouse clicks) if you only want to do the simplest thing: extract points from a 2D X-Y graph.

Very brief tutorial in 8 steps

  1. Clone this repository; then unzip.

  2. Open MATLAB, and then run ImgDigitizer.m from MATLAB.

(Click here to download the binary executable if you do not have MATLAB, or you prefer to run a compiled executable file.)

  1. This window pops out:

  2. Load an image from the hard drive. There are three sample images in this repository. Take Image3.png for example:

  3. Select the scales (linear or logarithmic) for X and Y axes, and then fill in the upper/lower limits of axes; and then use your mouse to pick the lower-left and the upper-right corner of the axes frame.

  4. Click "Start" to stark picking desired points on the graph. MATLAB prints a cyan/magenta mark on each point you pick.

  5. Hit "Enter" when you have finished picking the points. Then a new MATLAB figure window pops out, which displays the points you picked.

  6. Click the "Export data" button, then a CSV file will be saved to the MATLAB home directory. The content of the CSV file looks like this:


Copyright (c) 2014-2017, Jian Shi. See LICENSE.txt file for details.