With The Rules Of The Gas Pipeline Based On Semantics To The Study Of Comprehensive Pipeline Data Extraction Method

With the increasingly wide application of GIS data, the demand of data sharing in all industry is more and more urgent. But the data requirements are quite different from different domains, resulting in a large amount of data processing which are so prohibitive for many departments and exert a lot of influence on data sharing. Data ETL has been applied to data warehousing, knowledge discovery in databases and the overall quality of data management ripely. Its efficiency and convenience are recognized and praised by the majority of users. Based on the theory of data ETL, the paper developed a new method of acquiring the shared data. And then take the gas pipeline data for example to achieve the data ETL from special pipeline to complex pipeline. This method creates a new way to access to shared data, reduces the consumption greatly and enhances the operability of data sharing.To implement data sharing, how to solve the semantic differences between industries is the first problem. Therefore, in the beginning of the paper, it researches the data structures, sums up the semantic descriptions, dissects the discrepancy in semantics, feature type, attributers, topological relationship, builds the data description model of the two according to national standards.Based on all of aforesaid work, the corresponding relations between them are studied deeply and data transformation rules for the automatic extraction are refined. It designs the dynamic mapping algorithm adapting to the geometry types and semantic rules to realize the automatic mapping of the data semantics. According to the geometry, topology and semantic rules, the ETL functions are designed to complete the "one-stop" extraction of the gas pipeline data.The content and conclusions are as follows:(1) Sum up the semantic descriptions of gas pipeline and complex pipeline, build the pipeline data description model. Contrast to the data structure systems, analyze their differences and similarity and then take them as the starting point and way of the pipeline data ETL.(2) Refine the ETL rules of geometry, semantics, topology and attributes constraints in the data ETL process and design the uniform expression of the rules which make rules’storage and recalling easily.(3) Design the dynamic mapping algorithm adaptive to the geometry types. It can produce mapping results table automatically in response to the source semantics and target semantics and their geometry type, achieving the real-time dynamic mapping.(4) Propose efficient data ETL mechanism based on semantics and rules.According to the changes of the gas pipeline to complex pipeline, ETL functions are designed to complete the graphic, attributes, topology---"one-stop" processing and achieve a high degree of customization of the data with the guiding role of semantics and rules.