1D scatter to 2D intensity

I have a set of 1D waves which correspond to the x,y of an event. How to I convert this to an intensity plot. All three 1D waves have a random sampling.
I'd say you'd have to provide some more information first. You mention only x,y coordinates. What is the third wave?

You will probably want to set up a uniform grid (2D wave) scaled such that it includes the full range of x,y coordinates, initialize it to zero, and then loop over all of your coordinates, incrementing the value of the bin containing those coordinates by some number.