The diploma thesis presents a project to establish a geographic information system (GIS) for a gas pipeline network at Javno podjetje Energetika Ljubljana, a public undertaking with which we cooperated. Procedures for updating the pipeline network database are described in detail and certain spatial analysis procedures provided by the mentioned GIS are presented. Using the system, the
number of built and inactive gas connections or customers in the area of the Ljubljana City Municipality was estimated. The results revealed that most potential gas customers, from a total of 5.817, come from the eastern part of the Ljubljana City Municipality: in settlements Novo Polje, Polje and Vevče.