This page offers suggestions and citations of the uses of directory-based historical GIS projects.
City directories were, as noted elsewhere in this Guide, intended originally to be used "biographically"-- that is, used by people who were beginning with an individual person's name, and trying to find information about him or her keyed to that fact. They can still be used that way in studying history.
Biographical uses are by researchers who have found a person's name in the course of historical inquiry and are trying to find out more about him or her. Genealogical uses are by researchers who are doing research on a person like that at the behest of descendants, or, perhaps, lawyers in search of heirs to an estate. The two are addressed in this Guide together, as they differ only in the researcher's purpose.