A Java-based digital library portal for geography education

G-Portal is a Java-based digital library system for managing the metadata of geography related resources on the Web. In addition to providing a flexible repository subsystem to accommodate metadata of different formats using XML and XML Schemas, G-Portal organizes metadata into projects and layers, and supports an integrated and synchronized classification and map-based interfaces over the stored metadata. G-Portal also includes a classification subsystem that creates category structures and classifies metadata resources into categories based on user-specified classification schemas. Furthermore, G-Portal users can annotate resources and make their annotations available to others. In this paper, we describe the design and implementation of G-Portal and elaborate how Java is used to implement its features. G-Portal has been designed to be modular and some of the modules can be used as stand-alone tools. In this paper, we use UML notation to describe the detailed design of G-Portal and highlight some of the design decisions.