4. Web Feature Service¶
The OGC Web Feature Service Interface Standard (WFS) provides a standardized and open interface for requesting geographic features across the web using platform-independent calls. Rather than sharing geographic information at the file level, for example, the WFS offers direct fine-grained access to geographic information at the feature and feature property level. Web feature services allow clients to only retrieve or modify the data they are seeking, rather than retrieving a file that contains the data they are seeking and possibly much more.
The 3D City Database offers a Web Feature Service interface allowing web-based access to the 3D city objects stored in the database. WFS clients can directly connect to this interface and retrieve 3D content for a wide variety of purposes. Thus, users of the 3D City Database are no longer limited to using the Importer/Exporter tool for data retrieval. The WFS interface is platform-independent and database-independent, and therefore can be easily used to build CityGML-aware applications.
The 3D City Database WFS interface is implemented against the latest version 2.0 of the OGC Web Feature Service standard (OGC Doc. No. 09-025r2) and hence is compliant with ISO 19142:2010. Previous versions of the WFS standard are not supported though. The implementation currently satisfies the Simple WFS conformance class. The development of the WFS is led by the company virtualcitySYSTEMS GmbH, Berlin, which offers an extended version of the WFS with additional functionalities that go beyond the Simple WFS class (e.g., thematic and spatial filter capabilities and transaction support). This additional functionality may be fed back to the open source project in future releases.
The 3D City Database Web Feature Service is free software under the Apache License, Version 2.0. See the LICENSE.txt file shipped with the software for more details. For a copy of the Apache License, Version 2.0, please visit http://www.apache.org/licenses/.