Mashup of Geo and Space Science Data Provided via Relational Databases in the Semantic Web

Wednesday, 17 December 2014
Bernd Ritschel1, Christoph Seelus1, G√ľnther Neher2, Toshihiko Iyemori3, Yukinobu Koyama3, Akiyo Ishida Yatagai4, Yasuhiro Murayama5, Todd A King6, John S Hughes7, Shing F Fung8, Ivan A Galkin9, Michael A Hapgood10 and Anna Belehaki11, (1)Helmholtz Centre Potsdam GFZ German Research Centre for Geosciences, Potsdam, Germany, (2)University of Applied Sciences Potsdam, Potsdam, Germany, (3)Kyoto University, Kyoto, Japan, (4)Solar-Terrestrial Environment Laboratory, Nagoya, Japan, (5)Integrated Science Data System Research Lab., Tokyo, Japan, (6)University of California Los Angeles, EPSS, Los Angeles, CA, United States, (7)NASA Jet Propulsion Laboratory, Pasadena, CA, United States, (8)NASA Goddard Space Flight Ctr, Greenbelt, MD, United States, (9)Univ Massachusetts Lowell, Lowell, MA, United States, (10)Science and Technology Facilities Council, Didcot, United Kingdom, (11)National Observatory of Athens, Athens, Greece
The use of RDBMS for the storage and management of geo and space science data and/or metadata is very common. Although the information stored in tables is based on a data model and therefore well organized and structured, a direct mashup with RDF based data stored in triple stores is not possible. One solution of the problem consists in the transformation of the whole content into RDF structures and storage in triple stores. Another interesting way is the use of a specific system/service, such as e.g. D2RQ, for the access to relational database content as virtual, read only RDF graphs. The Semantic Web based -proof of concept- GFZ ISDC uses the triple store Virtuoso for the storage of general context information/metadata to geo and space science satellite and ground station data. There is information about projects, platforms, instruments, persons, product types, etc. available but no detailed metadata about the data granuals itself. Such important information, as e.g. start or end time or the detailed spatial coverage of a single measurement is stored in RDBMS tables of the ISDC catalog system only. In order to provide a seamless access to all available information about the granuals/data products a mashup of the different data resources (triple store and RDBMS) is necessary. This paper describes the use of D2RQ for a Semantic Web/SPARQL based mashup of relational databases used for ISDC data server but also for the access to IUGONET and/or ESPAS and further geo and space science data resources.

RDBMS Relational Database Management System

RDF Resource Description Framework

SPARQL SPARQL Protocol And RDF Query Language

D2RQ Accessing Relational Databases as Virtual RDF Graphs

GFZ ISDC German Research Centre for Geosciences Information System and Data Center

IUGONET Inter-university Upper Atmosphere Global Observation Network (Japanese project)

ESPAS Near earth space data infrastructure for e-science (European Union funded project)