Avery Index will allow you to search for articles with specific types of illustrations. Select "FG Illustrations" from the pulldown menu and type any of the following: aerial photographs, axonometric, charts, color, computer drawings, details, diagrams, drawings, elevations, figures, graphs, illustrations, isometric, maps, models, photographs, plans, portraits, sections, sketches, site plans.
You can combine one or more of these terms with standard terms (e.g., cathedrals).
The University Libraries have an extensive collection of maps and related sources, which can enable architects to plan sites. Many maps are stored in the offsite annex, so please ask for assistance in identifying and retrieving maps for your research project. The Fine Arts Library also collects books and journals with maps and other site drawings.