Research On Spatial Similarity Calculating Method Between GML Documents

With the implementation of GML international standard(ISO 191362007)and China national standard(GB/T 23708-2009),many by artificially created or spatial service automatically generated(such as WFS of OGC)GML data rapidly emerged in large numbers in the Internet environment,and the document data searching,extracting and mining,become a research hotspot in the field of geographic information retrieval.As the theory and method of geographic information retrieval,related research results about spatial similarity in the face with GML document data having multiple nested structure,rich semantic features and obvious spatial characteristic information,are faced with the drawbacks of the comprehensive calculation model deficiency.In view of this,this paper integrated spatial similarity and XML similarity related theory and method,oriented the spatial similar features of GML documents,proposed comprehensive calculation model and algorithm between GML documents which takes the document structure and semantic of schema,spatial geometry,spatial relationships and other GML spatial similar characteristics into account,and the reliability and accuracy of the results is verified by experiments.The main research contents and results are as follows:Firstly,through the analysis of the GML data model and the GML documents data characteristics,this paper designed the GML documents similar characteristic quantitative expression,specifically embodied as GML schema similar characteristics(structure similarity and semantic similarity)and GML Spatial data similar characteristics(geometric similarity,topological similarity,direction similarity and distance similarity),to provide theoretical basis for the spatial similar calculation between GML documents.Secondly,basing on the analysis of the similar calculation method between the traditional XML documents,and combining with GML feature data model and core model,this paper designed the GML schema structure and semantic similar calculation model and algorithm,and then formed the GML document schema similar calculation model which takes into the similarity of the structure(the number of the same elements,the level of the hierarchy)and the semantic(element name,data type,and the base constraint)account.The model described in detail the characteristics and calculation process of the schema similar measure between the GML documents.Thirdly,drawing on the traditional spatial similarity computing method,and basing on GML Geometric model,this paper designed the similar calculation models and algorithms about spatial geometry(point entity set,line entity set,surface entity set)and spatial relation between GML documents,and then formed the GML document spatial data similar calculation model which takes into the similarity of spatial geometry and spatial relation(topology,direction and distance)account.The model described in detail the characteristics and calculation process of the spatial data similarity measure between the GML documents.Lastly,comprehensively considering the schema similar calculation model and the spatial data similar calculation model between GML documents,this paper proposed the spatial similar comprehensive calculation model,which takes into the similarity of document model(structure and semantic),spatial geometry and spatial relation account,and then the algorithm was verified by experiments.Experimental results show that the algorithm not only achieves the overall measurement of comprehensive all kinds of similar characteristics,but also can ensure the reliability and accuracy of the results.