All models are gathered like shells around the field data as a core module. Core modules are used to save the spatial entities, e.g. points (0D, singular measurements), lines (1D and 1.5D, quasi-continuous data as logs or profiles), polygons (2D and 2.5D, e.g. geological maps or vertical cuts in quarries) and volumes (3D, e.g. from the geophysical exploration). These dataset go far beyond the needs of geographical datasets but it should be possible to connect them to a GIS, e.g. GRASS.
The second level should be used for the geological description and first interpretation, e.g. principal geology (lithology, genesis, stratigraphy), structural geology and tectonics, hydrogeology, engineering geology, mineralogy, geophysics.
The analysis and interpretation of data follows on the third level: uni- and multivariate analysis methods, geostatistical tools, multispecies- and multiphase diagrams, cross sections etc.