A floor plan of a building is the best way to investigate the relationships between spaces within that building as they occur ________.

A floor plan is a two-dimensional representation of a building, typically viewed from above, that shows the layout of the spaces within the building. It effectively illustrates how different rooms and areas relate to each other horizontally, which is essential for understanding circulation, organization, and functionality of spaces.

By focusing on the horizontal plane, a floor plan allows designers, architects, and users to easily analyze the flow from one area to another, the proximity of spaces, and how effectively they meet the needs of users. It is particularly useful in assessing spatial relationships like adjacency, connections, and distance, all of which are crucial in architectural design.

In contrast, options that involve vertical planes, 3D models, or schematic diagrams emphasize different aspects of spatial analysis. While those methods provide valuable perspectives, they do not prioritize the horizontal relationship between spaces as directly as a floor plan does. Thus, the floor plan is the most effective tool for investigating spatial relationships as they occur in a horizontal plane.