Encyclopaedic works in the online space represent a valuable resource that, through the development of network information systems and content organization, can be enhanced in the epistemological sense of disseminating consolidated content. This practice is already present in Wikipedia and various projects, and this new way of presenting online encyclopaedic content allows for more efficient user information retrieval and facilitates navigation when accessing content. It is, among other, based on metadata that provide a spatial reference to the published content in the online space. Although the spatial representation of encyclopaedic knowledge is a concept still under exploration (especially in the segment of spatial annotation as the first step in spatial representation), encyclopaedic works have already long approached it by creating thematic maps. Thematic maps, though fragmented, are a kind of proto-spatial representation of encyclopaedic knowledge, and contemporary spatial annotation and representation would imply a more comprehensive presentation (displaying the entire encyclopaedic knowledge, not just individual articles or parts of articles) that is virtual and interactive. For the start of the research the Croatian Encyclopaedia of Technology was used as a jumpingof point in the process of creating a model of spatial annotation and representation of encyclopaedias (encyclopaedic projects) in general (not just specialised encyclopaedias) and development of methodology for approaching spatial annotation and representation as a scientific contribution to the entire field of encyclopaedics. The dissertation research included a qualitative analysis of encyclopaedic articles, identifying types of data with spatial references typical for each article category, and then determining the types of data advisable to annotate (and later represent) for each category. The research found that article categories are indeed carriers of creating a future model of spatial annotation and representation of encyclopaedic knowledge. The possibility of using tools for automatic named entity recognition as assistance in finding spatially marked information was also explored. Furthermore, the alignment of findings from the initial research with the content of a general encyclopaedia (the Croatian Encyclopaedia was used here) was investigated to expand findings from a specific (technical) encyclopaedia to general encyclopaedias. This research identified the need for a good understanding of the subject matter of the encyclopaedic project to be spatially marked, and guidelines were defined on how to approach familiarizing oneself with the subject matter, involving the examination of thematic maps provided by the project and searching article texts for information that is spatially recorded in detail (especially concerning the recording of street names, and additionally if street names are accompanied by house numbers). As there is currently no defined metadata standard for geotagging encyclopaedias, several metadata standards in related areas were considered, concluding that the most favourable metadata standard for use in spatial annotation and representation of encyclopaedic knowledge is the one of the Text Encoding Initiative (TEI) with its multitude of existing structural elements. Based on the creation of unified spatial references (geotags) for individual article categories, a set of metadata was proposed, and a model for the spatial representation of encyclopaedic knowledge was developed. This fulfilled the goal of this doctoral dissertation, and was further confirmed by creating a prototype of the spatial representation of knowledge for the Croatian Encyclopaedia of Technology. The general scientific contribution in the field of encyclopaedics was achieved by defining a methodology for approaching spatial annotation and representation of encyclopaedic knowledge, based on two key steps – categorization of articles, and all the defined steps in annotation information for each category; and familiarization with the subject matter of the encyclopaedic project. These two steps (each containing additional steps defined by research results) serve as a guide for editors or information professionals in creating representations of encyclopaedic knowledge for their encyclopaedic projects, whether for encyclopaedic projects of general content or other specific non-technical fields.