Modeling the sharing of geographic data
The recent proliferation of computer networks and the resulting trend toward networked and distributed data base management systems has influenced significantly the sharing of geographical data. The traditional transfer medium of magnetic tape has been replaced by data communication networks and an interfacing strategy has been adopted world-wide which revolves around the use of interchange standards such as SDTS1, NTF2, and MACDIF3. The functionality and performance of contemporary geographical information systems will be enhanced through their utilization of the increased connectivity of computers. In this paper we develop a method for modeling the data transfer scenarios which occur in practice. We stress the importance of semantic information and show that its inclusion in a machine readable description of the syntax and semantics of transfer file formats allows practical solutions to be developed for problems that may be anticipated during the modeling process. This information is vital if software is to be generated automatically both for encoding and decoding data to and from the format, and for converting data from one format into another. We describe BQL, a notation for specifying transfer file formats, as an application of our ideas.
SubjectsFields of Research::280000 Information, Computing and Communication Sciences::280100 Information Systems::280101 Information systems organisation
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