Edward Ullman was an influential American geographer known for his work in urban geography and spatial analysis. He contributed significantly to the understanding of how cities develop and function, particularly through his theories on the importance of transportation and communication in shaping urban spaces. His research helped to establish the field of urban studies as a distinct area of academic inquiry. Ullman is perhaps best known for his concept of the central place theory, which explains the size and distribution of cities and towns. He also emphasized the role of location in economic activities, influencing how planners and policymakers approach urban development and land use.