8-bit maps of world cities

I was a little disappointed because I thought this would be about 8-bit isometric cities. Like Youcity, an isometric map of SF: http://youcity.com/2009/website_front/index.html#

And some cities based on OSM: http://bitsteller.bplaced.net/osm/

Love how they used the sprites from The Adventures of Lolo (http://nintendookie.files.wordpress.com/2010/04/adventures-o...) Makes me nostalgic. :)

Fun to see, familiar and new at the same time as intended.

For the Amsterdam map there appears to be a large part of what I know is water that is rendered green? Why is that?