Realistic contents related industries providing immersive and realistic feeling are being continually developed with the improvement of information and communications technology. In the area of geospatial information, real-world city models are increasingly used in various contents (e.g., movies, games, sports, or tourism). Given this trend, there is growing demand for sharing and opening 3D spatial information as infrastructure that creates added value by combining with numerous industrial domains such as virtual/augmented reality, disaster management, defense, or a smart city. In this paper, we introduce our nascent system for authoring and utilizing a realistic 3D geospatial city model.