From Sun Zhuo:
MicroCity is a framework for spatial analysis and simulation. It is lightweight, fast, portable, extendable and user friendly. Users can easily operate large GIS and Grid data and perform Spatial, Fractal, Network analysis and simulation. You can easily build your model based on efficient MicroCity Script and run it on the fly. There are enormous extensible modules can be downloaded from web. Both the User Interface and the Application Programming Interface are designed to be very intuitive. Because it's used SAGA api, SAGA modules are also reusable.