After many years I've taken another stab at the 3D image from the cover of the book "The beauty of Fractals." I think I got a lot closer this time. Like my previous attempt, the height values are calculated using Distance Estimate (DE) values I figured out that for the book cover image, the height value for pixels that are close enough to the set are forced to the highest hight value. This surrounds the satellite image with a flat surface, and means the fine filaments have a flat region around them, That makes the filaments look more like a raised path and less like a bumpy series of mountain peaks. I uploaded a photograph of the book cover for comparison:
The Beauty of Fractals cover image