One challenge that I have faced over the past few years is building a base map that will work in the mobile environment. The problem I have run into is the need to have a map that will be legible during the day while sunlight is shining on the screen and at night when it is back lit. As such I have been experimenting with a gray color scheme and introduce colors slowly only when necessary. Here are two recent interactive maps I have run across which also are following the same ideas I have been working on.