Introducing a Customized Framework for 3D Spatial Data Infrastructure of Iran Based on OGC Standards

This paper describes a framework for 3D geospatial data infrastructure based on Open Geospatial Consortium (OGC) Standards in Iran, especially Tabriz, as one of the oldest cities with more than 3000 years of history. The external code lists based on local culture, vegetation and heritage landmarks were proposed for indexing 3D city structures, buildings, statues and city furniture of Tabriz. These code lists can be used between different governmental agencies as a communication tool and utilized for indexing in the 3D spatial Database (DB). There are some predefined code lists from Germany as the founder of City Geography Markup Language (CityGML), which can be utilized for Iranian context, along with some defined codes based on local cultures and structures. These code lists can be defined for all street furniture, sculptures, and facade textures in some applications such as city planning, built environment, disaster management, and so forth. The code lists can also be used for the components of the buildings, for instance, the facade of the building in different layers as an entity or multi-patch feature class or implicit geometry such as windows, doors, and backgrounds. In addition, the code list can be used to index city elements and enhance the use of 3D SDI for a variety of privileges from end-users to professionals in the near future for different organizations and management levels. The framework for web-based CityServer3D application has been discussed in this research paper. CityGML, as a standard data exchange format, has been utilized for developing 3D SDI for Iran, and implicit geometry representation has been used to avoid lagging while rendering the 3D models during navigation in the 3D virtual environment. The Implicit Geometry Representation (IGR) has been defined in CityGML as prototypic geometry which can be parameterized for multiple usages (Löwner et al., 2016).