1. A method for radiometric normalization of a plurality of mosaic image layers having different spatial resolutions, comprising: first calculating first image metadata for at least a first image portion of a first mosaic image layer having a first spatial resolution, wherein the first image metadata is independent of the first spatial resolution; second calculating second image metadata for at least a second image portion of a second mosaic image layer having a second spatial resolution different than the first spatial resolution, wherein the second image data is independent of the second spatial resolution; determining a normalization function based on a comparison of the first image metadata for the first image layer and the second image metadata for the second image layer; applying the normalization function to the second image layer to normalize at least a portion of the second image layer relative to the first image layer.