G3data

G3data is an open source application which is used to extract data from graphs. Additional information is available at :  

http://github.com/pn2200/g3data

G3data is currently available on nodes tyr and thor. Some help is available with the command "g3data --help". To run g3data :

  • on the command line enter " g3data <filename>", where <filename> is the image file name with the graph you would like to digitize. <filename> can be of one of the following forms :

    JPEG, GIF, PPM, PGM, XPM, PNG, TIFF, EIM

  • after the window pops up, you must first set your (four) access points which define the range of the values which you will ultimately generate. Left-click on "Set Point X1". Left-click on the graph where X1 is to be. A little black symbol will appear on the graph. Enter the value in corresponding box at the top. Repeat this procedure for X2,Y1,Y2. After you enter the final value and enter carriage return, you should see the values in the boxes in the upper right-hand boxes change as you move the mouse across the graph.
  • you are now ready to select the point on the graph that are to be digitized. Move the mouse to a point you wish to digitize and left click once. Move to next point and repeat as many times as you wish. The point will appear as a small red box. To delete your points and start over, click on "remove all points". To remove axis points, click "Remove all points" a second time. Use the "Zoom Area" to finetune your point selection.
  • once all points are selected, click on "Export Point data". A second box will pop up. Choose your options. Typically, you will want to export data to a specific file. Click on "Print" to create file of data points.
  • to test, enter "g3data /tmp/test1.gif"

For assistance or more information, contact : System Administrator