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 (Lö wner et al., 2016).

Large amount of sediment deposits in the reservoir area can cause dam break, which not only leads to an immeasurable loss to the society, but also the sediments from the reservoir can be transported to generate further problems in the downstream catchment. This study aims to investigate the short-to-long term sediment transport and channel meandering process under such a situation. A coupled explicit-implicit technique based on the Euler-Lagrangian method (ELM) is used to solve the hydrodynamic equations, in which both the small and large time steps are used separately for the fluid and sediment marching. The main feature of the model is the use of the Characteristic-Based Split (CBS) method for the local time step iteration to correct the ELM traced lines. Based on the solved flow field, a standard Total Variation Diminishing (TVD) finite volume scheme is applied to solve the sediment transportation equation. The proposed model is first validated by a benchmark dambreak water flow experiment to validate the efficiency and accuracy of ELM modelling capability. Then an idealized engineering dambreak flow is used to investigate the long-term downstream channel meandering process with non-uniform sediment transport. The results showed that both the hydrodynamic and morphologic features have been well predicted by the proposed coupled model.

Nowadays, standardized metadata for geospatial data is a key in sharing and finding information on the web and crucial in building Geospatial Data Infrastructure (GDI). The main objective of this paper was to develop a web-based metadata dissemination system for in-situ sensors based on, most importantly, interoperable, standard and open technologies introduced by Open GIS Consortium (OGC), namely Geography Markup Language (GML). In this research, at first a use case diagram was developed to demonstrate the user’s requirement. Then, an application XML schema based on user’s requirement was created. To build this schema, some GML schema documents (developed by Open GIS Consortium (OGC)) were imported into the application schema. System architecture was designed based on client/server model and a UML class diagram was also developed to present all classes and their attributes, operations and associations within the system. Implementation was conducted using GML, XML, XMLHTTP, DOM, ASP, and VBScript that brought out a web-network-based in-situ sensors metadata application. This application provided a user friendly interface to search and find sensor related information. Results showed that although GML and XML are powerful tools to build geo-metadata, it is important to note that GML document size may be a problem when dealing with huge amount of data.

A great deal of research has been conducted on the performance of granular columns under vertical loads. However, in some situations, the movement of the soil mass can lead to lateral deformations and, as a result, shear stresses in the soil and columns. The primary objective of the present study is to numerically investigate the shear performance of soft clay soil improved with a single Ordinary Granular Column (OGC) in the direct shear test using a hybrid Discrete Element-Finite Difference Method (DEM-FDM). The numerical modeling method was first validated by simulating a direct shear test conducted previously on a soft clay-OGC composite in the laboratory. Afterward, an extensive parametric study was conducted to determine how various factors affect the shear strength of clay-OGC composites. According to the results, increasing the area replacement ratio from 15 to 35% can increase the peak shear strength of clay-OGC composites in the direct shear test by up to two times, depending on the level of applied normal stress. The micro-scale results also indicated that the surface roughness of soil particles in OGC has a greater effect on the shear strength of clay-OGC composites than their angularity. Furthermore, the results showed that the equivalent friction angle of clay-OGC composites should be calculated based on the residual friction angle of granular soil used in OGC.