# How to integrate in 2D, along the locus of a line.

If I have a 2D continuous and differentiable function (f(x,y)) and a general 2D line L (ax + by + c = 0), how do I evaluate the definite integral of f with respect to x and y along the line L between an arbitrary start and end point that both lie on the line?

Have a look at: http://en.wikipedia.org/wiki/Line_integral#Definition