Georeferencing and semantic annotations improve the findability of geoinformation because they exploit relationships to existing data and hence facilitate queries. Unlike georeferencing, which grounds location information in reference points on the earth’s surface, semantic annotations often lack relations to entities of shared experience. We suggest an approach to semantically reference geoinformation based on underlying observations, relating data to observable entities and actions. After discussing an ontology for an observer’s domain of experience, we demonstrate our approach through two use cases. First, we show how to distinguish geosensors based on observed properties and abstracting from technical implementations. Second, we show how to complement annotations of volunteered geographic information with observed affordances.