This paper addresses the methodological issues of developing and visualising added value geo-enabled content for mobile information systems. The research was carried out under the framework of WebPark, an EC-IST R&D project that developed a location aware application for nature/protected areas. The evaluation of existing information sources - tourism information, research data, and multimedia content - revealed that the tourism information and multimedia content analysed did not have an active geographic component and the geographic research data (e.g. animal counts/observations) had a clear mismatch as regards the visitors' information needs. Therefore, different types of data processing were developed and performed in order to render existing information sources useful for location-based services. Data preparation also included building hierarchical data structures (quadtrees and hierarchical stream ordering). The paper shows how these data structures are exploited to facilitate real-time generalisation in order to efficiently present thematic point data on portable devices. Finally, three key lessons for geo-enabling location-based services are presented.