The Doctoral Thesis has been focussed on examining aspects of interpretation and readability of visual representation, as well as on determining theoretical grounding for five criteria to characterize readability of visual representation in spatial planning documents in Latvia: (1) balanced diversity of the content categories and visual forms; (2) consistency of the visual language; (3) integrity of spatial dimensions and physical planning; (4) integrity of strategic and instrumental aspects; (5) appropriateness of the language for collaborative planning. Theoretical aspects of cross disciplinary interpretation and readability of visual representation from the perspective of semiotic and visually aesthetical approaches, as well as from collaborative planning comprise theoretical grounding of the research. Empirical part of the research examines historical aspects of visually representing spatial environment in Latvia, analyses requirements set out by the legal framework of spatial planning, as well as summarizes interviews with experts in the fields of planning and architecture in Latvia about readability of visual representation in spatial planning documents in Latvia. For the first time in the context of spatial planning in Latvia theoretical aspects of cross disciplinary interpreting visual representation have been jointly examined with the requirements set out by the legal framework of spatial planning in Latvia, as well as the analysis of developing spatial planning documents in Latvia.