Lch is similar to it's cousin Cie-L*ab, except that it's been rearranged in the shape of a sphere which makes it useful for applications like high-end photo editing and retouching images. Read more about it here
Xyz is an additive color space based on how the eye intereprets stimulus from light. Unlike other additive rgb like Rgb, Xyz is a purely mathmatical space and the primary components are "imaginary", meaning you can't create the represented color in the physical by shining any sort of lights representing x, y, and z. It's complicated to explain in a nutshell, so read more about it here:
Color conversions performed using the open source ColorMine library.
Cool! Creating famous images from color palettes found in other images: http://t.co/H1OxefkOt0