This article is a sample of green roofs mapping analysis, a method that provides data, which can be transferred into information about benefits and disadvantages of green roofs. E.g. how do they improve water retention? How does it affect local water management? How do green roofs reduce real estates energy demand? How many tones of air pollution do they reduce? What are their other benefits in specific to administrative area? What is the potential to build green roofs and benefits they might bring?