Metadata is “data that describe the data.” They show how, when, where and by whom the data were collected, their availability and distribution method, projection systems, and coordinates that characterize them, the methodology and the input scale, resolution, accuracy and reliability with respect to certain standards.

The purpose of metadata is to facilitate consultation and exchange of data and to enable their utilization. It is highly recommended to systematically associate metadata created in datasets, and to consult the metadata of existing data before using them. There are established standards for the metadata of geographic data, such as ISO 1915 or the FGDC standard. By organizing the data according to standards, it becomes easier to manage them effectively, to ensure quality and to share them. Most GIS software are based on these existing standards to ensure metadata management but there are also specialized tools in this area.
See also: Database
[French: Métadonnées]