U.S. Geological Survey Thesaurus

"The USGS Thesaurus is the principal controlled vocabulary supporting Science Topics. It is designed as a formal thesaurus conforming to ANSI/NISO Z39.19, with rigid adherence to the hierarchical (BT, NT) term relationships, generic non-hierarchical (RT) relationships, and lead-in term relationships linking non-preferred terms to descriptors either singly (UF) or in a compound USE-WITH relationship. The thesaurus is faceted, meaning its top terms delineate general aspects of information resources: Sciences: Major educational fields, fields of study, and professional groupings within USGS. Methods: Techniques, methods, procedures, or strategies for research, management, collection, or analysis of scientific information in USGS Topics: Themes, subjects, and concerns for which USGS information resources are relevant Product types: General representation of the information in a resource, such as a map or data set Time periods: Geologic time periods and seasons of the year USGS: Activities, processes, and organizational concepts relevant to USGS itself The thesaurus is limited in depth and specificity of coverage. It does not attempt to replicate existing controlled vocabularies such as GeoRef. The intention is to provide sufficient contextual cues for the information seeker to determine the relevance of a resource for his or her concern, not to locate precisely the answer to a specific user question. Each information resource in the Science Topics catalog is categorized using several index terms. Consequently a document will be listed under each category for which it would be considered a relevant resource. Approximately 1200 web resources are listed in the catalog."