EmCity is a simulation decision-making and analytical software tool for architetcs and urban planners. The tool is based on nonlinear and unpredictable agent-based simulation of urban growth and reconfiguration of the urban pattern that utilizes several computational algorithms in terms of Swarming behavoir, Stigmergy, Attraction and Path following. The tool provides observation and exploration of potentials of urban development and simulation of equable grainines of urban activities in South City in Prague based on approach distance as an essential bottom-up strategy of urban development. Thus the simulation model allows user to simulate the emergent behavior of the urban pattern utilising several parameters of leading of agent flows. There are several possibilities of exporting the model into graphical outputs for further obsevation, evaluation and consideration.