What role does a key map play in a set of blueprints?

A key map serves to give an overview of the entire project area and indicate where specific details can be found within the blueprints. It typically shows the layout of a site or building in relation to its surroundings, making it easier for readers to understand the context of the project. This overview is crucial for navigating between different sheets in the blueprint set, as it helps to pinpoint the locations of various features, elevations, and details that may be spread out across multiple pages. By using a key map, one can quickly locate specific information without having to scour through every sheet, thereby enhancing the efficiency of interpreting the plans.