Moving Between Standards (Crosswalking)

Crosswalks are human- or computer-readable documents that map metadata elements between different metadata standards.

Crosswalks can apply to content standards, vocabularies, or both. An automated crosswalk process may take an instance of a metadata description that is presented in a particular format and change the format and element names and the values within those elements (i.e., the vocabulary) to meet the requirements of the second standard.

Crosswalking is generally done when datasets using different metadata standards or vocabularies need to be integrated. For example, consider a website providing a searchable metadata directory. If the different datasets composing the directory were described using different standards and vocabularies, it would be difficult for a user to search across them effectively.

If someone was interested in wave height data, she might need to know to search for “wave ht (m)” in one dataset and “wave amplitude” in another. A crosswalk that defined these two elements as synonymous would allow a website to be constructed that allowed the user to search on either term, and retrieve applicable results from both datasets.

Due to the complexity of metadata content standards, there are few automated processes to crosswalk between content standards. Even in those cases where automated crosswalks exist, inevitably some information is lost when crosswalks are made. This is due to the complexity of the standards and potentially non-overlapping subject areas. When there are subject areas that do not overlap, even manual translation between standards does not result in complete information transfer.

The Crosswalk Process

The process of mapping between content standards or vocabularies is usually divided into the following steps: harmonization, semantic mappings, rules, and transformation. These are described in the next guide.

Suggested Citation

Graybeal, J., Isenor, A., Wang, H. 2009. "Moving Between Standards (Crosswalking)." In The MMI Guides: Navigating the World of Marine Metadata. Accessed: 06/29/2010

Suggested Citation

Wang, H., Isenor, A., Graybeal, J. 2011. "Moving Between Standards (Crosswalking)." In The MMI Guides: Navigating the World of Marine Metadata. Accessed July 16, 2020.