netCDF-LD SKOS: Demonstrating Linked Data Vocabulary Use Within netCDF-Compliant Files

Overview & Synopsis

netCDF, the widely-used array-oriented data container file format, has previously been extended in an initiative called netCDF-LD, to include Linked Data metadata elements. In this paper, we build on that initiative with demonstrations of a Simple Knowledge Organization System (SKOS)-aware file format and associated tooling. First, we discuss a very simple way to reference SKOS vocabulary data stored online in netCDF files via Linked Data. Second, we describe our prototype ncskos tools, including ‘ncskosdump’, which wraps the well-known ‘ncdump’ tool used to print out netCDF headers and data. Our tools utilize some of the features of Linked Data and SKOS vocabularies to enhance the metadata of netCDF files by allowing: multilingual metadata label retrieval; alternate term name retrieval; and hierarchical vocabulary relationship navigation. In doing this, ncskosdump preserves the ncdump practice of writing output in standard CDL (network Common Data Language). For the demonstration of theses formats and tools, we relate how we have included URI links in netCDF files to SKOS concepts within a demonstration vocabulary and how the ncskos tools can be used to manage these files in ways that are not possible using only regular netCDF metadata. We also discuss problems we perceived in scaling Linked Data functionality when applying it to large numbers of netCDF files or in multiple file management sessions, and how we have catered for these. Finally, we indicate some future work in the area of more comprehensive Linked Data representation in netCDF files.