Twentieth-century planners, architects, and landscape architects deployed a changing array of visual techniques to represent, analyze, promote, and forecast the American city. Maps and diagrams, in particular have been central tools interjected into every stage and scale of planning and design. But they are also images, with all of the complicated and rich implications of that term. Every plan is an act of persuasion, an argument for an alternative way of life that attempts to convince an audience of a potential future based on data culled from the present. This course is a selective tour through diagramming and mapping in architecture and urban planning, in particular at the scale of the city in the twentieth century. Literature drawn primarily from geography, cartography, art history, the history of science, and architecture will guide original student research culminating in a seminar paper. There will be a mixture of primary and and secondary literature. Topics may include Camillo Sitte's figure-ground diagrams, Colin Rowe's revival of Sitte's technique vis-a-vis Nolli's map of Rome, urban sections and transects, master plans, Edmund Bacon, Kevin Lynch, Venturi and Scott Brown, townscape imagery, graphic information, mapping movement, and systems diagramming.