Social and economic development has proceeded in parallel with energy production and this progress is influenced by the types of used energy sources. Increasing environmental problems originated by the widespread use of fossil fuels, have promoted the use of clean and renewable energy sources as solar energy and related technologies as photovoltaic panels and the photovoltaic applications. However, the use of these technologies is not that much common in urban areas with limited spaces for solar panel installation. In this context, building rooftops and facades are considered a potential installation spaces but the best locations for panel installation should be determined to understand the feasibility of the potential system installations in practice. This study basically aims to present a Geographic Information System based methodology for making a decision of photovoltaic installations on building rooftops in urban areas. For this purpose, a model was provided for determining the spaces available for photovoltaic panel installations on building rooftops and for performing feasibility analyses. The model used three dimensional point cloud data of the study area as input and produced building rooftops classified based on their availability for photovoltaic panel installation as a result of a Multi-Criteria Decision Making process.