Plot Digitizer is a Java program used to easily digitize scanned plots of functional data. Version 2.4.1 fixes a bug in the calculation of polygon areas.
Plot Digitizer 2.4.1 can be downloaded from:
https://sourceforge.net/project/showfiles.php?group_id=112725&package_id=121999&release_id=363708
What does this program do?
Often data is presented in reports and references as functional X-Y type scatter or line plots. In order to use this data, it must somehow be digitized. This program will allow you to take a scanned image of a plot (in GIF, JPEG, or PNG format) and quickly digitize values off the plot just by clicking the mouse on each data point. The numbers can then be saved to a text file and used where ever you need them. Plot Digitizer works with both linear and logarithmic axis scales. Besides digitizing points off of data plots, this program can be used to digitize other types of scanned data (such as scaled drawings or orthographic photos).
A special feature of this program is the ability to semi-automatically digitize lines off a plot. The user simply indicates where the line is on the plot with a thick paint brush and the program attempts to automatically sort out the data from grid lines, etc.
To make the digitizing task easier, this program includes many handy features. For example: You can recalibrate the Y axis without having to recalibrate the X axis (multiple sets of data are commonly plotted with the same X axis). You can insert points between two already digitized points by right clicking and choosing "Insert" from the pop-up menu. You can delete points by right-clicking on the points and choosing "Delete". You can move points by clicking and dragging them. You can calculate the length of a digitized line and the area enclosed by a digitized polygon of nearly arbitrary shape. Finally, there is also unlimited undo/redo.