The base sheet for the Duncan residence is shown in Figure 6-39. The base sheet should be generated first by drawing the property lines, house location, other structures such as detached garages, and all the existing site elements that are to remain unchanged and be incorporated into the design. Digital files can be backed up to a CD or external hard drive, whereas hand-drawn documents should be put away in a safe, dry, flat file. Once the site measurements have been taken and recorded, the base sheet and base map can be drawn. The base map can also be used as the underlying layer for creating functional diagrams (Chapter 8) and preliminary design studies on tracing paper (Chapters 9 through 11). Because these documents have a number of elements in common, it is useful to coordinate their preparation. Only copies of these original drawings should subsequently be used. Copies of the base sheet will serve as the beginning point in drawing the preliminary and master plans, and hard copies of the base map can be used for recording site inventory observations if this was not done previously while visiting the site to take measurements. The base map is completed by adding all other existing physical elements of the site onto the copy of the base sheet. If the base sheet is drawn by hand, then it needs to be reproduced onto high-quality paper via a copy machine. If there is any question about what existing site elements are to stay or be removed, then few or no site elements should be drawn. Selection of paper type and drawing medium, drawing scale, sheet size, and sheet layout are important factors to consider in drawing the base sheet and base map. If the base sheet is created in a digital form on the computer, it is easy to copy the file and rename it as the base map.