2d gradient map defined by set of curves or set of surfaces

Hi, I am doing the urban design project and I would like to generate a pixelized gradient map of zoning to envision the mix-use typology of the site.

To do that, I prepared a set of curves to design different types of use in the city and now I am looking for a solution on how to blend defined zones into one gradient of 7 colors.

The whole site will be mainly composed of 4 shades - blue/orange/pink/green based n curvature/surface definition and 3 additional colors representing the public spaces so it could be connected to the point definition.

Do you know how to control gradient by different curves and points to create one coherent picture?

Thank you for your help!