Introduction 

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.

The process starts with an image file containing a graph or map. You add three axis points to define the axes, then other points along your curve(s).The final result is digitized data that can be used by other tools such as Microsoft Excel and Gnumeric.

Engauge (from en "make" and gauge "to measure") verb meaning to convert an image file containing a graph or map, into numbers.

The term "Engauge" in Engauge Digitizer was invented for this project, since there seems to be no similar term in common use.

Why Would You Need This Tool?

Here are some real-life examples:

• You are an engineer with some graphs in decades-old documents, but you really need the numbers represented in those graphs so you can do analyses that will determine if a space vehicle is safe to fly.
• You are a graduate student gathering historical data from charts for your thesis.
• You are a webmaster with visitor statistics charts and you want to do statistical analyses.
• You ride a bike or boat and want to know how much distance you covered in your last trip, but you do not have an odometer or GPS unit. However, you do have a map.

Nice Features

• Automatic curve tracing of line plots
• Automatic point matching of point plots
• Automatic axes matching
• Automatic grid line removal for improved curve tracing
• Handles cartesian, polar, linear and logarithmic graphs
• Support for drag-and-drop and copy-and-paste makes data transfer fast and easy
• Image processing tools highlight data by removing grid lines and backgrounds
• Status bar suggestions guide beginners
• Context sensitive popup help windows reveal explain feature of the user interface
• Tutorials with pictures explain strategies for common operations
• Browser-based user manual is extensive yet easy to navigate
• Preview windows give immediate feedback while modifying settings
• Dates and times are imported with the Date/Time Converter
• Import support for common image file formats such as BMP, GIF, JPEG, PNG and XPM
• Export support for common software packages such as Microsoft Excel, OpenOffice CALC, gnuplot, gnumeric, MATLAB and Mathematica
• Engauge is available for a wide variety of platforms (Linux, Mac OSX, Windows)
• Engauge Digitizer is completely open source and free courtesy of Sourceforge, Github, Digia and FFTW