Chapter 1 Hierarchical Infrastructure for Internet Mapping Services

Abstract For years, the access to internet-based public mapping services provided by vendors such as MapQuest or MapsOnUs has changed little. The mapping service would generate maps of the viewed areas in raster format and transfer them in the form of images embedded in web pages to remote users. This approach is suboptimal for users who plan to explore a given area in more detail as the same data may be sent to the users repeatedly. In mid 2005, Google Maps and MS Virtual Earth improved upon this approach by dividing the images into smaller tiles which allows many of them to be reused in subsequent panning. This increases performance of such mapping systems substantially. In both cases, however, the client only has access to data converted in its raster format which prevents it from querying or re-processing the data locally. We investigate this opportunity for further improvement in providing the client with map data in vector format so that it can perform some operations locally without accessing the server. We focus on finding strategies for distributing of work between the server, clients, and possibly other entities introduced into the model for query evaluation and data management. We address issues of scalability for clients that have only limited access to system resources (e.g., a Java applet). We compare performance of the vector-based system with raster-based systems, both traditional (e.g., MapQuest) and tiled methods (e.g., Google Maps) for a set of common basic operations consisting of fine and fast scrolling and zooming (both in and out)