Model-driven approach for accessing distributed spatial data using Web Services – demonstrated for cross-border GIS applications (mdWFS)

The project aims at developing an approach for web-based schema transformation of geospatial data. It includes the specification of a conceptual language for defining schema mapping rules for semantic transformation as well as the specification of an interface for a model-driven web service able to carry out semantic transformation.

Project description

Schema transformation is identified as key interoperability issue in INSPIRE. To be able to perform schema transformation, the INSPIRE Directive suggests so-called transformation services. With these services, data requested by a user could be directly transformed to match the INSPIRE Data Specifications while the original data remains unchanged.

However, standards for transformation services do not exist up to now. Furthermore, most existing approaches define the translation between source and destination schema on the level of the data transfer formats (e.g. GML application schemas), and not on the platform-independent conceptual level (e.g. UML schemas). This shortcoming is addressed by the research and development project "Model-driven approach for accessing distributed spatial data using Web Services – demonstrated for cross-border GIS applications (mdWFS)" which is carried out by the Technische Universität München (TUM) and the Swiss Federal Institute of Technology Zurich (ETHZ) on behalf of the German Federal Agency for Cartography and Geodesy (BKG) and the Swiss Federal Office of Topography (swisstopo) from 2006 until the end of 2011.

The project aims at developing a transformation service, called mdWFS (model-driven Web Feature Service), which can carry out model-driven transformation of spatial data in a web-based environment. In this approach, the schema translation is defined on the level of the conceptual schemas and not on the level of the data transfer formats. The transformation of the spatial data can then be carried out automatically based on these conceptual definitions. The transformations are defined with the transformation language Unified Modeling Language for Transformations (UMLT) which was developed specifically for this approach. The transition from the conceptual to the format level is accomplished by using encoding rules.

Source schemas used in the project are the German Digital Landscape Model (ATKIS Base-DLM) as part of the AFIS-ALKIS-ATKIS Reference Model (AAA) and the Swiss Data Model TLM (Topographic Landscape Model). These schemas are transformed into the harmonised EU INSPIRE Data Specifications. A graphical UMLT editor is being developed for defining the transformation rules and for exporting them in the XML Metadata Interchange format (XMI) for further use as platform- and data-format-independent input to any transformation tool able to interpret XMI. Within the project the transformation is based on the transformation tool FME from the Canadian company Safe Software. Since the UML models and the UMLT transformation rules are provided in XMI, FME is being extended within the scope of the project by appropriate readers and transformers to be able to handle XMI.

Duration

2006-2011

Project sponsors

• Bundesamt für Kartographie und Geodäsie (BKG)
• Bundesamt für Landestopografie swisstopo

Contact person

• Dipl.-Inf. Tatjana Kutzner

Project leader

• Prof. Matthäus Schilcher

Project contributors

• Dr. Andreas Donaubauer
• Dipl.-Inf. Tatjana Kutzner
• Dipl.-Geogr. Astrid Fichtinger
• Florian Straub, M.A.

Projekt partners

• Eidgenössische Technische Hochschule Zürich, Institut für Geodäsie und Photogrammetrie