Image Processing- Endless Summer pictures

I am wondering if anyone has any techniques to make a picture look like the Endless Summer Poster. For those who don't know what the poster looks like, I've included a link below. I am familiar with numerous image processing techniques, but if anyone has any ideas, I'd love to hear them. Thank you. -Mike

http://theocnow.com/2010/11/15/endless-summer-poster-artist-coming-to-south-coast-plaza/

[Image Analyst]

It's basically a colormap but you have to have a good grayscale image to start with. Do you have some that you can post? Do they all have horizons like that picture? It looks like there may have been some clean up by hand to perfect the boundaries of the objects - they don't look perfectly natural.