Tactical diagramming is a technique used to determine floor plans by using outside architectural features such as doors, windows, vents, ducts and even the shape of the building itself. Using simple concepts like working from large to small and confidence to ambiguity, students gain knowledge, skills and abilities on how to identify architectural features that provide reliable clues to the locations of interior walls, the types and sizes of rooms and even the location of appliances and wall switches. The course begins with a broad overview on terrain analysis with a focus on urban terrain and the contribution of a reliable floor plan for planning and decision-making. It continues with an explanation of building principles, which heavily influence how residences are constructed. The course will also identify how to diagram houses that have additions or been remodeled, have upper-stories and even structures with multiple-dwellings. The course completes the formal instruction with methods for obtaining reliable intelligence, especially photographs, to enhance the detection of subtle architectural features. The final period is focused on a practical application where students work with each other and instructors on either a class project or using their own photographs, of an actual target location.