Call for Participation in the CityGML 3.0 development

Please note: This Request is scheduled to close on 10 June 2014.
Open Date: 
Monday, 19 May 2014 UTC
Closing Date: 
Tuesday, 10 June 2014 04:00 UTC

This Call for Participation seeks organizations and individuals to participate in the development of the next major version of the OGC City Geography Markup Language (CityGML).

CityGML is a comprehensive open data model framework and XML-based encoding standard for the modeling, storage, and exchange of virtual 3D city and landscape models. Since 2008, it is an international OGC standard. CityGML is implemented as an application schema of the OGC Geography Markup Language 3 (GML3) Encoding Standard (, an international standard for spatial data exchange and encoding approved by the OGC and ISO. CityGML is being implemented across Europe, Canada, the Middle East and Asia. It has even been adopted by several countries including The Netherlands and Germany as official national and municipal 3D geo information standard, and it has been adapted as part of the European Union's common spatial data infrastructure INSPIRE.

Since the release of CityGML 2.0, a number of CityGML change requests have been submitted to the OGC. In June 2013, further requirements and ideas guiding the development of CityGML 3.0 were gathered and discussed at an international workshop jointly hosted by the OGC and the Special Interest Group 3D (SIG 3D). All presentation slides and the minutes of the workshop are available here: . The outcomes of this ongoing discussion are formally captured in a list of work packages that define the overall work scope for CityGML 3.0. Examples of the identified work include changes to CityGML’s level-of-detail concept, additional semantic model structures such as building storeys, floor plans or utility networks, as well as new complex attributes like time series and metadata. To the extent feasible, new features will minimize impacts on backwards compatibility that might affect the many communities using the current version of CityGML.

The OGC solicits input and expertise from CityGML users, data producers, software vendors, and scientists in order to identify participants willing to contribute to and able to assume ownership for the work of the work packages under the joint leadership of the OGC CityGML Standard Working Group (SWG) and the SIG 3D. This call explicitly includes non-OGC members. Active participation in the CityGML 3.0 development process does not require OGC membership. To be most effective, organizations and individuals responding to this CFP should plan to fully participate in the CityGML 3.0 development activities.

The CityGML 3.0 work packages are as follows:

  1. Revise and maintain the UML representations of the conceptual model(s).
  2. Design and implement the standards document(s).
  3. Revise the level-of-detail (LoD) concept.
  4. Remove root-level inheritance from GML and separation of conceptual model and encodings.
  5. Develop a method to keep CityGML synchronized with changing GML versions.
  6. Develop a representation for changing content of entire models or parts of a model. This includes time-sequences of successive representations, simultaneously existing alternate versions, mobile objects, and dynamic objects.
  7. Develop a materials module and/or revise the textured surfaces module.
  8. Develop a representation for land administration.
  9. Develop a representation for non-building building-like structures.
  10. Develop a representation for utility networks.
  11. Develop a representation for volumetric construction and work toward harmonization with the Industry Foundation Classes (IFC).
  12. Develop representation for metadata, complex attributes, and harmonize with INSPIRE.
  13. Develop a representation for storeys (Am. “stories”) and other new semantic constructs.
  14. Develop or a mechanism for parameterized implicit geometries.

The work package list is publically available on GitHub at Interested parties are encouraged to register at the Wiki page of the work package(s) to which they wish to contribute by adding their

  • Name;
  • Organization(s);
  • Email address; and
  • Intended role (e.g., work package lead, editor, co-editor, contributor, reviewer)

to the list of participants.

Registration only requires a GitHub user account which can be obtained free of charge at The CityGML SWG intends to use GitHub as open platform for the management of work packages, discussion and issues, informative content, and publication of work results throughout the entire CityGML 3.0 development process. CityGML users are invited to use the GitHub platform to communicate existing or anticipated uses cases for CityGML to be considered in the development. If you are not familiar with GitHub, please contact the CityGML SWG Chairs who will assist you in registration.

Responses to the CFP are requested by the time of the 10 June 2014 kickoff of CityGML 3.0 development at the OGC Technical Committee meeting in Geneva, Switzerland. Note, however, that this CFP will remain open for the duration of the CityGML 3.0 development process.

About the SIG 3D

The SIG 3D is a special interest group of the German National Spatial Data Infrastructure (GDI-DE). The SIG 3D developed the first version of CityGML and in 2005 submitted CityGML as a candidate standard to the OGC. Subsequent versions of CityGML were jointly developed by OGC and SIG 3D based on a MoU between both organizations. The members of SIG 3D come from all over Germany and the bordering European countries. New members from anywhere in Europe are welcome.

About the OGC

The OGC is an international consortium of more than 480 companies, government agencies, research organizations and universities participating in a consensus process to develop publicly available geospatial standards. OGC standards support interoperable solutions that "geo-enable" the Web, mainstream IT, and wireless and location-based services. OGC standards empower technology developers to make geospatial information and services accessible and useful with any application that needs to be geospatially enabled.