The continuous theoretical development of the research area of spatial cognition is not accompanied by the practical application of the set postulates. Research challenge is recognised within the development of an appropriate way to translate the conclusions and relations of spatial cognition into a clear graphic system that enables better communication and cooperation of related disciplines. The hypothesis of the paper is that the theoretical conclusions of the analysed concept can be translated into space through visual reinterpretation - graphic processing used as a tool for review and translation. The research is conducted in two parts - the first analyses the historical development of theoretical thought about the relationship of spatial cognition and diagrams in architecture, while the second segment explores contemporary theoretical standpoints through six characteristics of schematic reasoning and validates them through relevant case study. This research aims to examine and define the process of conceptualisation of diagrams in the context of assessing cognitive variables of space. The diagram develops from a simplified graphic indication of space into an active participant in the modification of the urban environment. Research outcome is the definition of four schematisation principles, which describe concise cognitive potentials for illustrating the impact of space on the user.