Not that i have a solution for your particular problem but just do get a creative process running:
Consider, that you not only can differentiate data points by there position, but you can also alter size, color and maybe even shape of single points based upon certain values.

In reply to Re: [OT] Displaying 4D data in a 2D image. by Taulmarill
in thread [OT] Displaying 4D data in a 2D image. by BrowserUk

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