In this thesis, I propose a method of constructing semantic reference systems for geographic information based on reproducible observations. Similar to spatial reference systems, semantic reference systems consist of formal theories (reference theories) with conventionally established interpretations into perceptual and constructive operations (such as pointing to a physical monument, and describing locations relative to it). They can be used to annotate data and describe and compare their semantics.

The thesis addresses the grounding part of reference systems. I argue that persisting problems of information ontologies, namely the grounding problem and the problem of reference, could be solved using certain principles of construction and imitation in terms of perceptual operations. These operations focus joint human attention on pre-conceptual cognitive mechanisms, i.e. ‘Gestalts’, in the perceived space around the body. They also allow an observer to relate foci of attention based on the Gestalt. The memorized relations are expressed by observation predicates, to be established by convention in terms of speech acts of an observation language. These speech acts can be shared, and thus represent lowest level information items. I propose a kind of “practical constructivism” guided by a formal language. The idea is to describe data categories in terms of observation predicates, i.e. “bottom-up”, in order to reconstruct the underlying observation procedure, instead of presuming abstract concepts.

For example, bodies, surfaces, and different kinds of media in the human environment are grounded in terms of perceived affordances. Object properties such as waterdepth are grounded in experiential geometry, visual surfaces and media of diving. I propose a corresponding reference theory and put it to a practical test in this thesis: I define an essential road network category, namely a junction, and test the definition in Open Street Map.