This open source, digitizing software converts an image file showing a graph or map, into numbers. The image file can come from a scanner, digital camera or screenshot. The numbers can be read on the screen, and written or copied to a spreadsheet.

The process starts with an image file containing a graph or map. You add three axis points to define the axes, then other points along your curve(s).The final result is digitized data that can be used by other tools such as Microsoft Excel and Gnumeric.

Engauge (from en "make" and gauge "to measure") verb meaning to convert an image file containing a graph or map, into numbers.

The term "Engauge" in Engauge Digitizer was invented for this project, since there seems to be no similar term in common use.

Why Would You Need This Tool?

Here are some real-life examples:

Nice Features


Effort started in October 2014 to move to the Qt5 library. This will be a major upgrade with many new features. Work will be on github. Developers are encouraged to visit the Engauge 6 project page.

Engauge Digitizer was upgraded to Qt4 in late 2011 (thanks Tobias Winchen and Tobias Richter!). In version 5.1 some minor fixes were made, and point matching was fixed in Windows.

If you would like to monitor this software and receive email notification of new releases, click on the envelope icon on the Project Summary page. If you would like to suggest any new features, please use the Feedback page to privately contact the developers, or the Open Discussion forum.


Engauge Digitizer is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License (version 2) as published by the Free Software Foundation.

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