Index maps are a type of

finding aid A finding aid, in the context of archival science, is an organization tool, a document containing detailed, indexed, and processed metadata and other information about a specific collection of records within an archive. Finding aids often consist o ...

that enables users to find a set of maps covering their regions of interest along with the name or number of the relevant map sheet. An index map provides

geospatial Geographic data and information is defined in the ISO/TC 211 series of standards as data and information having an implicit or explicit association with a location relative to Earth (a geographic location or geographic position). It is also ca ...

data on either a sheet of paper or a

computer screen A computer monitor is an output device that displays information in pictorial or textual form. A discrete monitor comprises a visual display, support electronics, power supply, housing, electrical connectors, and external user controls. The di ...

. In this way, a map acts as a kind of

gazetteer A gazetteer is a geographical index or directory used in conjunction with a map or atlas.Aurousseau, 61. It typically contains information concerning the geographical makeup, social statistics and physical features of a country, region, or con ...

, with the location (such as a call number) represented within a grid overlaying the map's surface. One important reason for using

data instead of political borders is because the latter often change. Information is searched by coordinates, rather than the

metadata Metadata is "data that provides information about other data", but not the content of the data, such as the text of a message or the image itself. There are many distinct types of metadata, including: * Descriptive metadata – the descriptive ...

for a particular country and region that can be entered into a catalog. Additionally, in various institutions, maps are sometimes cataloged individually or as sets, resulting in various levels of specificity.

References

{{Authority control Index (publishing) Map types