DataThief III is described as 'program to extract (reverse engineer) data points from a graph' and is an app in the Development category. There are more than 10 alternatives to DataThief III for Windows, Linux, Mac and Online / Web-based. The best alternative is Engauge Digitizer, which is both free and Open Source. Other great apps like DataThief III are WebPlotDigitizer (Free, Open Source), Plot Digitizer (Free, Open Source), g3data (Free, Open Source) and GraphClick (Paid).
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.
A large quantity of published data is available only in the form of plots and it is often difficult to extract numerical data accurately out of these pictures. There are several softwares available to aid this process, but most are either paid or poorly written.
Plot Digitizer is a Java program used to digitize scanned plots of functional data. Often data is found 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.
GraphClick is a graph digitizer shareware for Mac OS X which allows to automatically retrieve the original (x,y)-data from the image of a scanned graphor fom QuickTime movies. Free download. Features automatic detection of solid, dashed or dotted lines, bar charts or symbols.
jTechDig is a software tool written in Java for digitizing data from an image of graph or plot. jTechDig can import images from .gif, .bmp, .png etc. files. After mapping of the coordinates system the data can be digitized manually by clicking the mouse.
Sometimes it is necessary to extract data values from graphs, e.g. in most scientific publications only plots but no data values are published. DigitizeIt makes it easy to actually get back numbers from such a plot!