Procedural modeling of city generation:

As the game industry is advancing, and the video cards are becoming more powerful, the need for more powerful expressive graphics obviously increase. using modeling techniques to generate such graphics is desirable as it reduces the costs.desire for more details in the graphics .using generation techniques, each graphic can be generated by calling a function with some parameters. these parameters could determine the shape of the tree , or its color . or even some patter it has. and by such making it different form other generated trees. here is few approaches :

• L-system: used to model plants,it uses rewriting of the graphics by modeling bacteria division populations.
  
• Perline noise : uses parametric control and allows for minimal storage management.
• Tiling : using random distribution function, for placing tiles or objects to create textures .
  
• Veroneri Texture basis : place dots randomly , draw lines to produce cellular textures .
• the main goal is to look realistic rather than behave realistic .

so after looking at this , the question is this ? can we extend this to model generation of complete cities ?