Lessons Learned in Generating Crosswalks for Earth Science Metadata

In order to facilitate interoperability among Earth Science data systems, NASA recently completed a project in which the metadata of three systems were mapped to each other and to standards published by the Federal Geographic Data Committee (FGDC-STD-001-1998 and FGDC-STD-012-2002). While studying the metadata and developing the crosswalks, several themes emerged that apply to any type of metadata and that need to be addressed to ensure that future systems and standards maximize interoperability: - definitions need to be complete, unambiguous, and further clarified using examples. - mapping one set of metadata to another can be highly subjective. - documentation needs to be written for an audience much less familiar with the metadata than those that developed it. - automated translation of one type of metadata to another requires diligent human input. The mappings resulting from this project and additional information are available to all on the HDF-EOS Tools and Information web site. For each set of metadata, the following are provided: each entity (or class) and its definition and associated attributes; each attribute, its definition and class path, and a mapping of each attribute to attributes in the other data systems and standards.