1. IRI Data Library Faceted Search: an example of RDF-based faceted search for climate data Drawing on multiple ontologies to build an application Using inference to connect ontologies describing different parts of the framework http://iridl.ldeo.columbia.edu/ontologies/

2. Faceted Search http://iridl.ldeo.columbia.edu/ontologies/query2.pl?...

3. Distinctive Features of the search Search terms are interrelated terms that describe the set of returns are displayed (spanning and not) Returned items also have structure (sub- items and superseded items are not shown)

4. Architectural Features of the search Interface is generated from a set of Terms connected to a set of Items Multiple search structures possible Multiple languages possible Search structure is kept in the database, not in the code http://iridl.ldeo.columbia.edu/ontologies/query2.pl

5. Search Interface as Multiple Ontologies Search Interface Users Datasets Search Ontology Dataset Ontology Additional Semantics

6. Ontology Types Attribute Ontology (e.g. Dataset) Object Ontology (essential for crosswalk) Term Ontology (e.g. search ontology)

7. Attribute Ontology Subjects are the only type-object Predicates are “attributes” Objects are datatype Isomorphic to simple data tables Isomorphic to netcdf attributes of datasets Some faceted browsers: predicate = facet

8. Object Ontology Objects are object-type Isomorphic to “belongs to” Isomorphic to multiple data tables connected by keys Express the concept behind netcdf attributes which name variables Concepts as objects can be cross-walked Concepts as object can be interrelated

9. Example: controlled vocabulary {variable} cfatt:standard_name {“string”} Where string has to belong to a list of possibilities. {variable} cfobj:standard_name {stdnam} Where stdnam is an individual of the class cfobj:StandardName

10. Example: controlled vocabulary Bi-direction crosswalk between the two is somewhat trivial, which means all my objects will have both cfatt:standard_name and cfobj:standard_name

11. Example: controlled vocabulary If I am writing software to read/write netcdf files, I use the cfatt ontology and in particular cfatt:standard_name If I am making connections/cross-walks to other variable naming standards, I use cfobj:standard_name

12. Term Ontology Concepts as individuals Simple Knowledge Organization System (SKOS) is a prime example The ontology used here is slightly different than SKOS: facets are classes of terms rather than being top_concepts

13. Nuanced tagging Concepts as objects can be interrelated: specific terms imply broader terms Object ends up being tagging with terms ranging from general to specific. Search can then be nuanced tagging can proceed in absence of perfect information

14. Faceted Search Explicated

15. Search Interface Items (datasets/maps) Terms Facets Taxa

16. Search Interface Semantic API {item} dc:title dc:description rss:link iridl:icon dcterm:isPartOf {item2} dcterm:isReplacedBy {item2} {item} trm:isDescribedBy {term} {term} a {facet} of {taxa} of {trm:Term}, {facet} a {trm:Facet}, {taxa} a {trm:Taxa}, {term} trm:directlyImplies {term2}

17. Faceted Search w/Queries http://iridl.ldeo.columbia.edu/ontologies/query2.pl?...

18. RDF Architecture RDF Virtual (derived) RDF queries

19. Data Servers Ontologies MMI JPL Standards Organizations Start Point RDF Crawler RDFS Semantics Owl Semantics SWRL Rules SeRQL CONSTRUCT Search Queries Location Canonicalizer Time Canonicalizer Sesame Search Interface bibliography IRI RDF Architecture

20. Cast of Characters NC – netcdf data file format CF – Climate and Forecast metadata convention for netcdf SWEET - Semantic Web for Earth and Environmental Terminology (OWL Ontology) IRIDL – IRI Data Library

21. CF attributes SWEET Ontologies (OWL) Search Terms CF Standard Names (RDF object) IRIDL Terms NC basic attributes IRIDL attributes/objects SWEET as Terms CF Standard Names As Terms Gazetteer Terms CF data objects Location

22. See Also http://iridl.ldeo.columbia.edu/ontologies/ http://iri.columbia.edu/~benno/Talks/AGU2 007Poster.pdfhttp://iri.columbia.edu/~benno/Talks/AGU2 007Poster.pdf