quantaize data and build an histogram

Hello,

I have a 3D data (X,Y,Z). Where X is between 0 to 360, Y is between 0 to 180 and Z is between -100 to + 100.

I'd like to quantize the data to NxM scale values on X and Y axes respectively and to have some mean value for Z.

This data shall be displayed on 2D plot where the Z values shall be represented by colors (if value is close to 100, then green, if the value is close to -100 then red).

How this could be done?