Postprint version. Published in Lecture Notes in Geoinformation and Cartography, The European Information Society, Part 1, January 1, 2007.
Presented at 10th AGILE International Conference on Geographic Information Science: Aalborg, Denmark, May 8-11, 2007.
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The definitive version is available at http://dx.doi.org/10.1007/978-3-540-72385-1_1.
Given the great demand and promise for educational use of GIS, real time access to massive remote geospatial datasets for pedagogical purposes would be immensely useful to educators and students. However, such access has remained elusive. In other work, we have demonstrated that a P2P distributed system of client-side proxies can address the challenges posed by the interactive, multiplicative, and exploratory nature of classroom GIS, and we described this system at a high level. In this paper, we present the details of several novel techniques that enable P2P cooperative caching and prefetching of OGC WMS data in an educational lab environment, via an implicit and flexible pyramid tiling scheme, a query smoothing heuristic, and statistical prediction. The techniques are standards-compliant and client-transparent, and provide dramatic improvement in user response times while reducing impact on remote WMS servers.