Comments on OGC CityGML Standard

CityGML allows users to employ virtual 3D city models for sophisticated analysis and display tasks in different application domains such as pedestrian navigation, environmental simulations, urban data mining, facilities management, real estate appraisal, and location based marketing.

CityGML has been implemented in many software solutions and is in use in many projects around the world. Developed for Urban Information Modeling applications, CityGML plays an important role in bridging Urban Information Models with Building Information Models (BIM) to improve interoperability among the information systems used in the many areas of activity that involve design, construction, ownership and operation of buildings and capital projects.

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 the International Organization for Standardization (ISO).

The current version 1.0 of CityGML was adopted as an official OGC Standard in August 2008 and has come to wide use since then. The OGC Technical Committee's CityGML Working Group has received input from the wider community in the form of change requests, proposed additions and suggestions. With this guidance, the Working Group developed the draft CityGML Version 1.1, a minor revision of the current CityGML version 1.0 that maintains backwards compatibility with version 1.0.

Version 1.1 includes new thematic modules for tunnels and bridges, the ability to model footprint and roof edge representations for buildings in the coarsest level of detail, and generic attribute sets, as well as a number of additional properties and other enhancements.

The candidate CityGML Version 1.1 standard documents are available for review and comment at the website below.