g3data is not available for Mac but there are some alternatives that runs on macOS with similar functionality. The best Mac alternative is Plot Digitizer, which is both free and Open Source. If that doesn't suit you, our users have ranked more than 10 alternatives to g3data and six of them are available for Mac so hopefully you can find a suitable replacement. Other interesting Mac alternatives to g3data are GraphClick (Paid), jTechDig (Free, Open Source), UN-SCAN-IT (Paid) and DigitizeIt (Paid).
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!
DataThief III is a program to extract (reverse engineer) data points from a graph. Typically, you scan a graph from a publication, load it into DataThief, and save the resulting coordinates, so you can use them in calculations or graphs that include your own data.