I'm working on an alien planet design in Photoshop, and I'm wondering if there are any brushes or techniques for easily creating that "city lights from space" effect? I'm hoping to create a randomized field that I can apply to various images, mimicking the clusters (i.e. big cities), smaller lights (i.e. towns), and lines (i.e. roads) to create a convincing sense of civilization.
It doesn't need to conform to any coastlines, etc, as I can handle that later with masks. Just a black background with grayscale pinpoints, following this type of structure, in a random pattern.
Ideally, it would be easy enough to produce that I could crank out several versions quickly, and the pinpoints would be of varying lightness so that I could filter by a luma value (e.g. "everything above 50% lightness") to simulate varying levels of population density on the same landscape (i.e. "here's a planet barely colonized, and here's that same planet densely colonized").
Does a system like that exist?