Metadata means 'data about data'. The term is used to describe the summary information about the characteristics and availability of a set of data.
For geospatial information, this normally means the What, Who, Where, When and How of the data. The only major difference between geographic metadata and the many other metadata sets created for libraries, academia, professions, etc., is the emphasis on the spatial component: the Where element.
As geospatial data is increasingly being stored in electronic format, the value of metadata is that it makes it easier to manage or find information. Some metadata records may even provide a link to download or purchase the data directly.
Metadata standards
Metadata standards used for documenting GI datasets are promoting consistency in structure and terminology. Metadata standards are necessary to ensure that comparisons can be made by users about the suitability of data from different sources. This assists interaction between different organisations.
Standards available in the UK
The International Standard ISO 19115/19139 for geographic information metadata was released in January 2003. Work on this standard has brought together the experiences of 33 countries, some with pre-developed standards on GI metadata.
The standard defines the schema required to describe geographic information and services, and provides information about the identification, extent, quality, spatial reference and distribution of digital geographic data.
ISO 19115 is the content part of the standard while ISO 19139 is the XML schema implementation that supports it.
The Dublin Core Metadata Initiative provides simple standards to facilitate the finding, sharing and management of information.
There are three formally endorsed versions of the Dublin Core Metadata Element Set, version 1.1:
The Gigateway Discovery Metadata Specification (PDF, 337KB), formerly the NGDF Standard, was the standard formulated by the National Geospatial Data Framework and was renamed in 2002. It is essentially the Dublin Core Metadata Standard with an extension for handling spatial coordinates.
This specification has now been superseded by the UK GEMINI (Geo-spatial Metadata Interoperability Initiative) Standard which was launched on 12 October 2004.
The e-Government Metadata Standard lists the elements, refinements and encoding schemes to be used by the public sector when creating metadata for their information resources or when designing search systems for information systems. This standard forms part of the e-Government Interoperability Framework and is required to ensure maximum consistency of metadata across public sector organisations.
The main focus of geographical data metadata has been data discovery and access, which means that a limitation of current metadata standards for data preservation is that they do not record how data has been processed and why.
Metadata catalogues
Geographical information metadata standards are being implemented to varying degrees by a wide range of organisations. Examples of geographical metadata catalogues are given below. Submitting dataset metadata to an online catalogue is the best way to promote its availability to others.
Resource Catalogue
Our Resource Catalogue contains 'signpost' information describing available data and intelligence resources. Items in the catalogue are classified according to the Integrated Public Sector Vocabulary.
Infrastructure for Spatial Information in Europe (INSPIRE)
The INSPIRE initiative intends to trigger the creation of a European spatial information infrastructure that delivers to integrated spatial information services.
These services should allow the users to identify and access spatial or geographical information from a wide range of sources, from the local level to the global level, in an interoperable way for a variety of uses.
Gigateway
Gigateway is a free web service aimed at increasing awareness of and access to geospatial information in the UK.
Use the Data Locator to find out what geographic datasets exist, and the Area Search to find out more about where you live. The Data Directory helps you locate organisations that supply geographic data, products and services.