It is often necessary to reverse engineer images of data visualizations to extract the underlying numerical data. WebPlotDigitizer is a semi-automated tool that makes this process extremely easy:

• Works with a wide variety of charts (XY, bar, polar, ternary, maps etc.)
• Automatic extraction algorithms make it easy to extract a large number of data points
• Free to use, opensource and cross-platform (web and desktop)
• Used in hundreds of published works by thousands of users
• Also useful for measuring distances or angles between various features
• More to come soon...