Research On Building Ontology-based Knowledge Base For Cartographic Generalization

Cartography scholars have got a common view that cartographic generalization need to be intelligent,and expert system should be used to solve the problems in cartographic generalization.Knowledge is the basis of realizing intelligence,the way to obtain and express cartography generalization knowledge and use them making reasoning effectively and correctly is the key to realize intelligent cartographic generalization.With the popularization and deepening of the application,knowledge sharing,interoperability,maintainability and so on is becoming more and more important,the traditional method of knowledge representation of cartographic generalization is unable to fill the requirements.As not only can ontology define the concepts(terms)of mutual recognition within the territory,but also rich semantic relationships between these concepts(terms),and it also can grasp the concept used by cartographic expert and the method which used by expert to solve problem properly.At the same time,ontology has some obvious advantages,such as knowledge sharing and reusing,solving problem through knowledge reasoning.Considering the above factors,this thesis proposes an approach to build knowledge base with ontology.The research contents and results of the paper are listed as follows:(1)This thesis sums up the research status abroad and at home of cartographic generalization and ontology-based knowledge base,and analyzes the necessity of building cartographic generalization ontology-based knowledge base.By studying the concept and connotation of ontology,and summarizing the common methods of ontology building of different domains,a method and step of ontology building in cartographic generalization domain is put forward.The theories,methods and technologies of ontology knowledge base are introduced,such as constitute,building steps and reasoning process of ontology knowledge base.(2)Taking road network selection as the specific goal of application,a cartographic generalization ontology knowledge base is built,thus improves the sharing,reusability and maintainability of knowledge.Firstly,with the help of experts,we extract 86 concepts and 27 properties,then use Protege4.3 to build cartographic generalization ontology,and use OWL DL ontology language to convey the ontology model.Secondly,the complex relationship between road network selection and the road attribute information and spatial relationship of road network is studied,and the demand of 1:10 0000 topographic map about road selection is considered,then we summarize 13 rules of road-network selection,and use Jena rules grammar to launch the formal representation of rules.Finally,the above knowledge is stored in MySQL database,so that the ontology-based knowledge base and the rule base of cartographic generalization is built.(3)By exploring the structure principal and architecture of cartographic generalization ontology based knowledge base system,a cartographic generalization ontology-based knowledge base prototype system of cartographic generalization domain is designed and developed,it can realize the automatic selection of road-network based on ontology knowledge base,then improve the degree of automation and intelligent of cartographic generalization.