Generic XML-based framework for metadata portals

Abstract

We present a generic and flexible framework for building geoscientific metadata portals independent of content standards for metadata and protocols. Data can be harvested with commonly used protocols (e.g., Open Archives Initiative Protocol for Metadata Harvesting) and metadata standards like DIF or ISO 19115. The new Java-based portal software supports any XML encoding and makes metadata searchable through Apache Lucene. Software administrators are free to define searchable fields independent of their type using XPath. In addition, by extending the fulltext search engine (FTS) Apache Lucene, we have significantly improved queries for numerical and date/time ranges by supplying a new trie-based algorithm, thus enabling high-performance space/time retrievals in FTS-based geo portals. The harvested metadata are stored in separate indexes, which makes it possible to combine these into different portals. The portal-specific Java API and web service interface is highly flexible and supports custom front-ends for users, provides automatic query completion (AJAX), and dynamic visualization with conventional mapping tools. The software has been made freely available through the open source concept.

Dicoogle, a Pacs Featuring Profiled Content Based Image Retrieval

“…Given that Lucene is a full-text search engine and not a conventional database, numeric fields are converted to lexicographic sortable string representations and the search mechanism is based on a trie algorithm as presented in [39].…”

Data sharing in the sciences

“…Many of these data collections provide discovery services through a portal (Ruusalepp, 2008). A metadata portal is an internet site that provides an integrated access interface to distributed information resources (Myers et al, 2005; Schindler & Diepenbroek, 2008; Wright, 2009). Portals are also used for cross‐domain searching (Treloar & Wilkinson, 2008).…”

PANGAEA - An ICSU World Data Center as a Networked Publication and Library System for Geoscientific Data

“…In addition, the PANGAEA R group has implemented a number of community and project specific metadata portals. The portal framework is generic and based on the components harvester, indexer with search engine (Apache Lucene 11 ) and corresponding API (Schindler and Diepenbroek, 2008) 12 . Examples are the portal for the International Ocean Drilling Program 13 and for the EU projects EUR-OCEANS 14 and CAR-BOOCEAN 15 .…”