1, a bottom-up construction method, which extracts entities, attributes and relationships from data sources in openurl and adds them to the data layer of knowledge map; Then these knowledge elements are summarized and sorted out, gradually abstracted into concepts, and finally form a pattern layer. 2. Top-down construction method: build the pattern layer of knowledge map, start with the top-level concepts, build the top-level ontology, and then refine the concepts and relationships to form a well-structured concept hierarchy tree.

Knowledge map, also known as scientific knowledge map, is called knowledge domain visualization or knowledge domain mapping map in the field of library and information science, which represents the relationship between knowledge development process and structure. 、