People have been relying on Google Maps, MapQuest, or other similar services to find desired locations on maps, browse surrounding businesses, get driving directions, etc.. Navigation by clicking and dragging the mouse to browse maps at multiple levels of resolution is one of the most attractive features in Web-based map exploration. Most database systems, though with some graphical user interfaces, are still lack of data-content browsing-based interfaces. Motivated by Google Maps, we develop DataScope, a Web-based data content visualization system, for people to view the desired data easily, interactively, and at multiresolution.

There are several challenging issues for developing DataS-cope:(1) unlike maps, which use well-defined and wellunderstood numerical metrics of longitudes and latitudes to position objects on the screen, there is no universally accepted way to design layout and visualize data points for relational databases;(2) different users may have different preferences on the importance of particular data values and on the weights or relevances of participating attributes; moreover, even the same user may have different preferences on the data based on the context of the query;(3) the data is often organized in multiple relations in a database, or associated with multiple hierarchies or semantic links; and finally,(4) a powerful query engine is the key to enabling a smooth and fast user interaction. The above challenges have been addressed in the design and development of the DataScope1 system prototype. We present a user interface that is conceptually similar to Google Maps based on the following principles. First, the Webbased interface provides a set of intuitive mapping operations such as rolling-up, drilling-down, zooming, and panning to help users navigate the database easily. Second, ranking is integrated with the map-browsing operations to provide