GeoGML - a GML3-based application model for geo- morphic Objects Marc-Oliver Löwner 1 1 Institut für Geodäsie und Photogrammetrie / Technische Universität Braunschweig m-o.loewner@tu-bs.de Here we propose an GML based application schema for geomorphic purposes that ful- fils the following requirements: First, an object-oriented view of landforms with a true 3D geometric data format. Second, the internal structure and attributes of landforms can be stored. Third, the interaction of processes and landforms is represented. Fourth, the change of all these mentioned attributes over time was considered. Worldwide geographical data can be shared over the Internet using Web Feature Ser- vices (Vretanos, 2005; Lake et al., 2004). The precondition is the development of a se- mantic model or ontology (rf. Fonseca & Egenhofer, 1999) based on international stand- ards like GML3 as an implementation of the ISO 109107 and others. Here we present a part of such a GML3-based application model for features and processes of the science of geomorphology as a precondition for data exchange. As the science of the land’s surface Geomorphology investigates landforms, their change, and the processes causing their change (Hugget, 2003). The main problem of comparing research results in geomorphology is that the objects under investigation are composed of 3D-geometries that change in time due to processes of material fluxes (e. g. soil erosion or mass movements). They have internal properties (e. g. soil texture or bulk density) that determine the effectiveness of these processes but are under change as well. Commercial GI-software is not adapted to the needs of the science of geomorpho- logy. Therefore the development of an application model i.e. a formal description of se- mantics is imperative to partake in technologies like Web Feature Services supporting interoperable data transfer. We represent the spatial properties of landforms by objects of GML3's geometry model as it is the implementation of the standards ISO 19107, Spatial schema (Herring, 2001) and others. We use a subset of the GML3 geometry package only that is quite similar to that of CityGML, an OGC Standard for modelling 3D-Virtual-Cities (Gröger et al., 2005; Gröger et al., 2008). The proposed model is a first step to enable researchers to share information about land- forms via the Internet using an OGC’s Web feature service. In this vein comparing mod- elling results of landscape evolution with results of other scientist’s observations is made easy. Compared to prevalent data concepts the model presented makes it possible to store information about landforms, their geometry and the characteristics in more de- tail. Although in a very juvenescent status, it allows to represent the 3D-geometry, the set of material properties and the genesis of a landform by associating processes to a geoobject. Thus, time slices of a geomorphic system can be represented as well as scen- arios of landscape modelling. Current geo-information systems are not in the position to