DataGraph is described as 'simple and powerful graphing application for Mac OS X. It is a great companion for Excel, Numbers or any of the big statistical packages'. There are more than 25 alternatives to DataGraph for a variety of platforms, including Windows, Mac, Linux, the Web and iPhone. The best alternative is LibreOffice - Calc, which is both free and Open Source. Other great apps like DataGraph are LibreOffice - Draw (Free, Open Source), Microsoft Office Excel (Paid), Google Drive - Drawings (Free) and Gnumeric (Free, Open Source).