Links and Resources
3. Metadata standards
With an increasing focus on geodata sharing and geodata integration into corporate information systems, the development of metadata standards has become a priority. A few of the existing metadata standards are listed below:
- Metadata "in the Dublin Core style", is metadata designed for interoperability on the basis of Semantic Web or Linked Data principles. Metadata in this style uses Uniform Resource Identifiers (URIs) as global identifiers both for the things described by the metadata and for the terms used to describe them.
- ISO 19139/19115 is the metadata standard dedicated to the spatial data documentation (ISO 19139:2007 and ISO 19115:2005) and identifies an extended set of metadata elements required to describe geospatial data. Explore yourself.
- ISO 19119 describes the structure of a metadata model for spatial web service instances to help searching, discovery and using available services (ISO 19119:2003) .
- FGDC (Federate Geographic Data Committee) standard is one of the earliest attempts to devise a standard for geospatial metadata. In 1994 the first version of this standard known as Content Standard for digital Geospatial Metadata (CSDGM) has been adopted. The second version was adopted in 1998.
- INSPIRE Metadata Implementing Rules define the guidelines for documenting the spatial data shared across EU Countries National profiles: besides the acknowledged international standards, national metadata profiles are developed in order to document the spatial data according to the national rules and regulations: e.g. data access policies might be different from one country to another and therefore additional metadata elements might be required to document the new data sharing policies
There are two main rules that apply to metadata:
- a discrete resource should have a discrete metadata record (1:1 rule)
- metadata must be exchangeable and parseable (Metadata has be expressed into a language that can be understood by computers).
As you already know, data documentation is encoded into XML Language. XML encoding is not enough for consistent data documentation. Therefore, a XML Schema defining the metadata elements is also required. This schema defines metadata elements and has been specified by ISO/TC211. Here you can have a look at ISO/TC 211 Metadata Schema and learn more about it.