Integrating graphical curves

[pezman]

Here's an interesting idea that I saw on another forum.

If you have a graphical plot, you can use GIMP to integrate curves. You can take pictures of curves, fill in portions of them and then do a pixel count. The number of pixels are an integral of the filled in region. In general, the scaling of the region has no bearing on the physical units of the problem, but you can do dimensionless measurements (e.g. comparison of portions of a curve).