Precision Image Digitizer – Trace & record the coordinates of your selected points in a JPG, GIF, or BMP. Point and click on the points in the image that you would like to record. The coordinates are displayed on the screen as you click them and they can then be exported to an ASCII text file, exported to an AutoCad DXF file, or printed. These files can then be imported into any other program capable of reading in text files or DXF files. You can also use the Windows clipboard to copy and paste images into and out of the program. The point coordinates are measured in pixels from the zero location (0, 0) at the lower left of the image. The horizontal axis is X, the vertical axis is y. You can assign a scale factor to the coordinates so the numbers on the bottom of the screen are displayed in real units such as inches. Setting the scale factor is very easy. Just click on two points on the image where you know the distance between the points
Only problem is 0X,0Y is at lower left of screen and not center.... but i'm sure there are ways around this.
Hope it helps
Okay, ignore the above.
use this: http://digitizer.sourceforge.net/ It seems much better and is open source so we can change it for our own needs.
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. The final result is digitized data that can be used by other tools such as Microsoft Excel and Gnumeric.