Object-Oriented Geological Symbol Database Design And Implementation

The map symbol is a semantic description in the process of real-world geographic space to map space data transformation.Symbols are used to represent the content of the elements in the map.The performance of the symbol library affects the quality of maps and the speed of map data acquisition.In map mapping,although the symbol library system of the existing GIS platform implements basic mapping requirements,the current rendering of symbols still needs further improvement in terms of accuracy and standardization.Based on the above analysis,we urgently need to produce a set of symbol databases that can meet the requirements of our country's industries,store them conveniently,and ensure that our symbols are effective.Through the careful study and induction of the geological map legend GB958-99 of the geological industry,in order to establish a more universal and shareable symbol database,this paper combines the basic theories of cartography and object-oriented,trying to symbolize Starting from itself,we study and analysis the mathematical model of the object-oriented symbolic object that has a high degree of conformity with the symbol,and standardize and define the map symbol from the perspective of the model.The main work of this article includes the following three aspects:(1)Study the concept of map symbols,and summarize and summarize the types of map symbols.Based on this,define the basic attributes of symbols,namely,position attributes,content attributes,and style attributes,and combine object-oriented thinking with them.The parameters are elaborated to provide ideas for the subsequent creation of symbolic object models.(2)Create a mathematical model of symbol objects and design a database of geological symbols.Firstly,the process of map symbol abstraction is studied.Based on the attribute parameters of symbol,a mathematical model of the symbol object is proposed.That is,the symbol object is formed by a certain combination of position,content,and style.Secondly,it analyzes the specific symbol structure.In accordance with three basic attributes to verify the correctness and validity of the mathematical model;Finally,combined with the 958 standards of China's geological industry,the clear relationship between the attributes of each symbol object and the hierarchical relationship between objects,the use of object-oriented theory based on the relationship between the database storage management symbol information Complete the design of the conceptual model,logical model,and physical model of the geological symbol database.(3)Combining with the geological remote sensing project to interpret product rapid mapping system project,design a common symbol library access interface for the created symbol database,achieve the standardization of geological symbols and cross-platform use,and compare the test results to verify the model established in this paper.Normative and effective.This paper aims to create a universal set of symbolic object models.According to the specific analysis of model attributes,a set of geological symbol database is designed to meet the needs of China's current geological industry development,and it can also realize that the symbol library can be compatible with other systems.Development and use of other systems to achieve symbol sharing.