Improving Metadata Compliance for Earth Science Data Records

Wednesday, 17 December 2014
Oliver Chang, University of Miami, Miami, FL, United States, Edward M Armstrong, NASA Jet Propulsion Laboratory, Pasadena, CA, United States and David Foster, Applied Science Associates, Wakefield, RI, United States
One of the recurring challenges of creating earth science data records is to ensure a consistent level of metadata compliance at the granule level where important details of contents, provenance, producer, and data references are necessary to obtain a sufficient level of understanding. These details are important not just for individual data consumers but also for autonomous software systems. Two of the most popular metadata standards at the granule level are the Climate and Forecast (CF) Metadata Conventions and the Attribute Conventions for Dataset Discovery (ACDD). Many data producers have implemented one or both of these models including the Group for High Resolution Sea Surface Temperature (GHRSST) for their global SST products and the Ocean Biology Processing Group for NASA ocean color and SST products. While both the CF and ACDD models contain various level of metadata richness, the actual “required” attributes are quite small in number. Metadata at the granule level becomes much more useful when recommended or optional attributes are implemented that document spatial and temporal ranges, lineage and provenance, sources, keywords, and references etc. In this presentation we report on a new open source tool to check the compliance of netCDF and HDF5 granules to the CF and ACCD metadata models. The tool, written in Python, was originally implemented to support metadata compliance for netCDF records as part of the NOAA’s Integrated Ocean Observing System. It outputs standardized scoring for metadata compliance for both CF and ACDD, produces an objective summary weight, and can be implemented for remote records via OPeNDAP calls. Originally a command-line tool, we have extended it to provide a user-friendly web interface. Reports on metadata testing are grouped in hierarchies that make it easier to track flaws and inconsistencies in the record. We have also extended it to support explicit metadata structures and semantic syntax for the GHRSST project that can be easily adapted to other satellite missions as well. Overall, we hope this tool will provide the community with a useful mechanism to improve metadata quality and consistency at the granule level by providing objective scoring and assessment, as well as encourage data producers to improve metadata quality and quantity.