Ok now that I worked on the detail level (generate small houses with street lamps...), it's time to start the generation of the whole world.
For this, I use a 50x50 heightmap which represent the world (an island to avoid invisible walls when the player reaches the border of the map). Each pixel of this 'macro' map represent a 100x100 map. If we consider that a character of the game map represent one meter, the whole world will represent a 25 square kilometer surface to explore which is enough to keep the adventurer busy for a while (don't forget there will be underground caves with several levels...)
Anyway I set up rapidely an heightmap generator and here is what I get from it. The height of a region will have impact on its content (for exemple, low : desert, middle : forests, high : snow).