In recent years, the World Wide Web (WWW) has undergone several important changes in terms of available applications, architecture, and related technologies. The need for a more effective resource sharing through the Web raised awareness on efforts aiming to enable machine-to-machine applications on top of the Web architecture by making semantics explicit. These efforts are currently coordinated in the W3C Semantic Web Activity which “provides a common framework that allows data to be shared and reused across application, enterprise, and community boundaries […]. It is based on the Resource Description Framework (RDF)” (W3C, 2011). At the same time, new use cases, new available applications and technologies have made possible the WWW revolution which is known as Web 2.0 (O’Reilly, 2005). This term actually refers to an entirely new paradigm in the use of the Web as a platform for applications characterized by features like: delivery of services instead of packaged software, with cost-effective scalability; control over unique, hard-to-recreate data sources that get richer as more people use them; trusting users as co-developers; harnessing collective intelligence; leveraging the long tail through customer self-service; design of software above the level of a single device; lightweight user interfaces, development models, and business models (O’Reilly, 2005; O’Reilly & Battelle, 2009).
These two main changes jointly make new resources available, and new technologies to discover them through semantic relationships. Unavoidably, these changes would and should affect the geo-information sharing domain that is mostly based on web paradigms and technologies. Recently many efforts aim to provide more powerful tools for the discovery of geospatial information that is made available through traditional or Web 2.0 services, basing on explicit or implicit semantics (Klien, et al., 2004; Smits & Friis-Christensen, 2007; Lemmens, et al., 2006; NASA-JPL, 2011).
Information technology and geo-science are worlds in continuous change. Semantics and Web 2.0 are the present challenges, but new ones will emerge in the future. This raises the conceptual issue of enhancing geospatial information discovery capabilities in order to accommodate present and, possibly, future needs. This chapter describes two approaches based on the methodology of augmenting semantically the discovery process to enhance the search and retrieval of geospatial resources.