EN/CityGML-Tutorial/chapter-1:-Intro-CityGML.md

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 In CityGML 3.0, only the UML model is defined in the conceptual model standard document. Unlike CityGML 2.0 multiple encodings can exist for CityGML 3.0 to encode the conceptual (UML) model. One encoding is the [XML](https://github.com/opengeospatial/CityGML-3.0Encodings/tree/master/Moved_to_CITYGML-3.0Encoding_CityGML) encoding. A free java tool to convert datasets from CityGML 2.0 to CityGML 3.0 is available [here](https://github.com/tum-gis/citygml2-to-citygml3). Other encodings such as CityDotNet, CityJSON, CitySQL are under [development](https://github.com/opengeospatial/CityGML-3.0Encodings).
 
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+**Previous Chapter** [Home Page](https://transfer.hft-stuttgart.de/gitlab/coors/3d-stadtmodelle/-/wikis/home)  
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 **Next Chapter** [chapter 2: Building](https://transfer.hft-stuttgart.de/gitlab/coors/3d-stadtmodelle/-/wikis/EN/CityGML-Tutorial/chapter%202:%20Building)  
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 ## References:
 
 [OGC CityGML standard](https://www.ogc.org/standards/citygml)