Spatial interaction is a research area within geography and urban planning that focuses on understanding and modeling the flow of goods, people, information, and resources between different locations. This field examines patterns of movement and connectivity within and between geographic areas, and seeks to explain the factors that influence spatial relationships and interactions. Researchers in this area often use quantitative methods such as gravity models, network analysis, and spatial statistics to analyze and predict spatial interactions. The findings from spatial interaction research can be used to inform urban planning, transportation systems, economic development strategies, and other areas of policy and decision-making.