Checkerboard islands

One final pastime for which I've used the random, hand-drawn checkerboards I've been writing about is generating lo-fi island maps.

To start, I'd create a large grid. This is one is about 100×100:

Starting at the upper right, I'd color alternate regions blue, but only if they bordered the edge of the grid:

That made some ocean. Regions touching ocean would become beach:

Regions touching beach became rocks:

Regions touching rocks became grass:

And regions touching grass became forest:

All other regions became mountains:

Then I'd repeat the process with the still-unshaded regions, ocean to beach to rocks to grass to forest, and finally mountains:

Here's the final map, without grid lines: