Color sample pr. polygon for maps

[monomagnus]

I'm making maps using terrain data, displaced meshes and Google Earth as textures, but the textures always looks like ass.

Realizing a stylized version would work, I'm wondering if it's possible to make an Octane material that samples the average color pr. polygon of the texture?
Removing the phong tag from the mesh and having each polygon have a single color based on the average beneath it (like Average Blur in Photoshop) will surely look
a lot nicer and still keep the main colors of the map.

Any takes?

Thanks!