As the ADL Gazetteer Content Standard shows (discussed in the "Models of Gazetteer Data" section below), the description of named geographic places can become quite complex if you design for documenting all aspects of placenames, place typing, geospatial referencing, relationships between places, changes through time, and other descriptive information. On the other hand, it is well established that a subset of this information is all that is needed to support basic documentation of named places for information management and retrieval. There are three core elements of a gazetteer entry:

• A name (could have variant names also)

• A class/type (selected from a typing scheme of categories for places/features)

• A location (a footprint; coordinates representing a point, line, or areal extent)

These three elements can be represented as a tuple of N, t, g, meaning that the gazetteer entry has at least one name, one type, and one geospatial footprint. Table 5.1 shows three examples of gazetteer entries containing these basic elements. These core elements permit translation from one place element to another, and this capability supports powerful functions in information services, such as allowing searchers to

• Search a catalog by starting with a placename and expanding the search to the geospatial location, thus retrieving items such as remote sensing images or maps that...