Galdos Systems, as one of the original creators of the standard, has a long-standing history with GML schemas and data. Based on the Geography Markup Language (GML) standard, CityGML is becoming a de-facto standard for representating and exchanging 3D city models. CityGML captures topographic objects in cities and regional models in terms of their appearance, but also with respect to their geometric, topological, and semantic properties.