It is the central goal of the STREAMER project to develop advanced design methodologies and tools for new or largely retrofitted buildings in hospital districts. In this context, an important approach is to base the design process on an integrated, semantically structured data model of the planned building and the existing neighbourhood ("Design-model"). In the various phases of the design process, different software tools supporting modelling, assessment, simulation or visualization need to access the design model. STREAMER task 6.3 aims at identifying potential interoperability issues of the involved software tools and at developing strategies for solving these issues. This report documents the main results of this research.
In STREAMER, the main reason for interoperability problems is the use of software applications from different technological areas. Among these are tools from the area of Building Information Modelling (BIM), Geospatial Information Systems (GIS), and tools for energy demand simulation. Consequently, this report first of all reviews the relevant standards for data models and web-based data exchange in the different areas. It is found that different standards are being used in the BIM and GIS areas. Big differences exist on the conceptual level already. In the BIM area, conceptual data models frequently are represented in EXPRESS, while many GIS standards use the Unified Modelling Language (UML). The Semantic Web domain mainly uses ontologies for data modelling purposes, but this technology is less supported by commercially available design tools.
The most important data model in the BIM area is "Industry Foundation Classes" (IFC) developed by buildingSMART (bSI). It supports all phases of a building’s life cycle and all building-relevant processes. For specific tasks in the design process, additional BIM standards may be relevant: BIM Collaboration Format (BCF) for supporting communication between different BIM tools, Green Building XML (gbXML) as an exchange format for energy simulation systems, VDI3805 / ISO /DIS 16757-1 for the exchange of product data in the area of heating, ventilation and air conditioning (HVAC), and the International Reference Life Cycle Data system (ILDC) format for the integration of life cycle information.
In the GIS area, a large number of different standards for buildings and energy-relevant data exist. The most prominent one is the City Geographic Markup Language (CityGML), an international standard for virtual 3D city models. In addition, potentially STREAMER-relevant standards have been developed for the European geospatial data infrastructure INSPIRE. Furthermore, a large number of building models are represented in Keyhole Markup Language (KML). Unfortunately, most of these standards hardly support energy-relevant attributive information. In this context, it is important to note that CityGML implements an intrinsic extension mechanism. Furthermore, a large amount of public available GIS information does not fit to any of these standards. As a consequence, it will be necessary in STREAMER to also access data in proprietary formats like ESRI Shapefile, and to use the very large database of the OpenStreetMap (OSM) initiative.
For web-based access to model data, BIM and GIS also use different standards. The report gives a short overview of the most import web service standards for GIS information developed by the Open Geospatial Consortium (OGC). The "BIM Server Information Exchange" (BIMsie) standard from buildingSMART is mentioned.
It is unlikely that all STREAMER-relevant data will be available in a uniform data format, which is supported by all system components. The main part of this report therefore discusses a number of technologies for mapping one data model onto another one. This will be illustrated by STREAMER relevant examples. In a "transformation", when taking into account geometry as well as semantics of the objects involved, the target model has less than or an equal amount of information as the initial model. If it is necessary to add specific information prior to the transformation, the process is called "data enriching". Mapping strategies are not needed in case an application supports more than one exchange format and is able to generate a consistent internal data model based on different data sources. The IFCExplorer application makes first steps in this direction, which are described in this report.
Data linking is an alternative approach to consolidate different data sources. On a lower level (e.g. references to externally stored documents, databases or code list registries), this technology is supported by most of the BIM and GIS data models mentioned. Semantic web technology also allows for data linking on a semantic level, provided that ontologies suited for the data models involved and their mutual correspondences are available. It is not yet clear whether corresponding data will be available in the STREAMER project, and for which processes they are used, if necessary.
Finally, the report lists a number of recommendations for the usage of standards and mapping techniques. The principal strategy should be to generate a consistent IFC model, which is maintained over all stages of the design process. For selected modelling and evaluation processes, which are supported by tools without adequate IFC support, the usage of other data formats will be unavoidable. In these cases, suited linking, transformation or data enriching strategies need to be developed. This is also necessary when the IFC based design model has to be consolidated with GIS data of the neighbourhood in an application that does not support different data models.