Multiple maps are generally used when displaying the same data over separate
time periods (in such cases a common scale and legend are important) or when displaying differing geographic extents that all have related data. Additionally, multiple
maps may be required when ancillary data that contribute to the overall map purpose
need to be displayed but are not central to the main purpose. Multiple maps on one
layout can be highly informative as they offer on‑the‑fly analysis by the viewer of
the map, thus making the map interactive and more likely to endure in the viewer’s
memory. Whether your layout will contain one map or many, the map element(s) will
be your primary means of conveying information to the viewer and therefore will
likely be the layout element that takes, by far, most of your time to create and polish.
Indeed, Chapter 6 is devoted solely to the techniques used in developing and refining