City lights texture for area not in the sun

[lazd]

A texture of global city lights should be shown on the dark side of the earth.

A city lights texture is provided by James Hastins-Trew here. We also have access to the 4k versions of it.

[lazd]

Some resources: http://en.wikibooks.org/wiki/GLSL_Programming/Blender/Layers_of_Textures