Geographic information systems performance in a broadband communications environment

Developments now taking place in computer hardware and broadband data communications promise to provide users hundreds of miles apart with access to the same equipment and data at comparable levels of performance. However, before adopting such technology, both suppliers and potential customers in the spatial data handling community require a clear understanding of potential network usage and the performance, capacity and cost tradeoffs involved. This research tests the hypothesis that broadband communication networks possess the performance necessary for organisations to manage their geographic information system (GIS) software and databases from a single location while maintaining satisfactory response times to end-users. Approaches to determining representative GIS operations and network usage patterns within an organisation are proposed and tested under actual operating conditions. Controlled experiments measuring GIS performance across high-speed metropolitan area networks are then described, and the corresponding results are compared for different organisational configurations, over varying distances and under different simulated loading conditions. Experimental results using Telecom Australia's 10 Mbit/sec FASTPAC service indicate that satisfactory file transfer and GIS performance can usually be maintained even over long distances. Specific Network File System (NFS) characteristics which adversely affect response-time performance under certain conditions are identified, and operational tradeoffs are assessed using a model of the current FASTPAC tariff structure. Finally, the implications and applications of broadband communications networks in the spatial data handling community are discussed and possible extensions to the research are identified