After doing the comparison of analog vs digital collage, I decided to experiment more with digital collage to see what else was possible. I looked through my image collection for a landscape that was contrasty and had a limited number of colors and found this one that I did a few years ago on my iPod Touch.
I pulled it into a layer in Inkpad, which is a vector based app on the iPad, and outlined the major shapes in another layer. This allowed me to alter the shapes and fill them with colors. I exported the image and modified it using a number of other apps.
iPad 3, Inkpad, Sketch Club, Pixelromatic, iColorama, Image Blender, and Photogene apps.
Jim