SCALE-DEPENDENT TRANSMISSION OF SPATIAL VECTOR DATA ON THE INTERNET

초록

This paper proposes a new transmission method, namely, Scale-Dependent Transmission, which handles large spatial vector data sets on the narrow-bandwidht Internet. Generally, spatial vector data, carrying richer information than raster data, provides a flexible and effective application of Gographic Information Systems on the Internet. But it is a problem to transmit large and complex spatial vector data on the narrow-bandwidth network efficiently, which have to be solved for publishing spatial information in format of vector on the Interne. Because spatial features are associated wiht scale in nature, not all feautrs are visible on a map at a certain scale. In this paper, the main idea is "Transmit what can be seen". Using map generalization and guided by Favorable Generalization Policy, the proposed method enables a server to eliminate invisible feautres according to the display scale and then to transmit only visible features so as tod reduce the response time for individual operations. According to the results of our experiments, the response time of individual operations has been reduced substantiallu by the usage of the proposed method.