Gazetteer (Flat Vocabulary)

Definition of a Gazetteer

In the context of metadataData about data. Metadata provides a context for research findings, ideally in a machine-readable format. It enables discovery of data via an electronic interface, and correct use and attribution of findings. Related Guide, a gazetteer is a very specific type of flat controlled vocabularyA managed list of terms. In the context of vocabularies, management typically includes careful selection of terms, maintenance of terms over time (i.e. addition, deprecation, modification), and presentation of the vocabulary in an accessible format. Related Guide - a geographic term list.

Discussion

The term "gazetteer" is used in a variety of ways. In the context of metadata, a gazetteer is a very specific type of vocabulary - a geographic term list. The vocabularies we've discussed up to this point articulate a list of terminology - in a gazetteer, the terminology is replaced with location names. The additional information provided by a vocabulary becomes a methodology to find that particular location (lat/lon, x/y, etc). A taxonomy exists to provide coordinates for a list of locations. In a global environment, this is very important. "North" to one person is "South" to another. Perhaps a project has broken the globe into a set of very specific regions - without a gazetteer, these very specific regions become vague and meaningless. For systems to be able to communicate effectively, location must be clearly articulated.

By necessity, a gazetteer will encompass a GISGeographic Information System (geographic information system). As such, it can take the form of an XMLeXtensible Markup Language file, ArcGIS layer, shapefile, or location information file designed for a home-grown interface. The main point of a gazetteer is to identify a "location" within a standardized coordinate system.

Example - National Geospatial Intelligence Agency Country Files

This gazetteer (represented in a table for display purposes), which is available online, is presented in a fairly extensive columnar format. Each area is completely described in one row of this text document. In the case of this gazetteer, documentation provided by the managing body is extremely important. Without that document, you might be able to guess that LAT is latitude in decimal degrees, but you might not understand that DMS_LAT is latitude in degrees, minutes, seconds. In addition, there are codes that are used throughout this gazetteer, to indicate things like a region code, or a feature classification. This is an excellent example of a gazetteer that also makes use of a code list. Neither the gazetteer or the code list would make sense without the other vocabulary.