A GML Documents Stream Compressor*

摘要

GML has become the standard format for geographical data transfer, exchange and storage. Usually, in GML documents there are many verbose tags and a large amount of coordinate data, which makes them be of extremely large volume. Thus, it is necessary to compress these documents to reduce storage and transmission cost. GML data is often stored and transferred in the form of multiple documents. Although some GML compressors have been developed recently, all of them can process only a single GML document at a time. In this paper, we propose a stream compressor for GML documents, called GDScomp, which can compress a stream of multiple GML documents effectively. It shares the structural information among multiple GML documents by a common dictionary to employ the dynamic compression method and uses the delta compression method for the coordinate data. Experimental results show that GDScomp can achieve satisfactory compression performance when compressing GML documents streams.