Three main theories of urban spatial design are discussed:
1. Figure and ground theory examines the relationship between solid urban masses (buildings) and open voids (spaces). It aims to establish a hierarchy of enclosed spaces through manipulating the pattern of solids and voids.
2. Linkage theory is based on "lines" that connect urban elements. It focuses on designing networks of paths, streets, and linear open spaces.
3. Place theory combines the above by giving contextual meaning to spaces based on cultural and human factors. A place is complete when architecture achieves a sense of unity and is visually appropriate for the context. Together, the theories aim to comprehensively understand and design urban form and spaces.