This paper introduces a methodology for the development of a high quality 3D city model using geographical informational system (SIG) tools and its possible applications in urban planning decision making. The approach used for modelling discusses the use of SIG instead of traditional CAD modelling. The final model includes an average total of 16.468 buildings in an area of 4,5 km_, with over 500,000 polygons. The longer term aim is to incorporate new data to the model including trees, urban furniture, new urban projects and be able to apply real-time queries for use as a public urban planning and evaluation tool.