Research On Downsizing Rule Base Of City DLG Data

The reduction of DLG data can be classified as the research field of map generalization.In recent years,the research on map generalization has focused on the field of automation.However,the existing automated DLG map reduction methods are low in systematization and are difficult to adapt to actual production requirements.Urban DLG data The study of downsizing rule base is an exploration of automation,systematization and application of map generalization.The article takes DLG data downsizing rules as the core,analyzes and researches the downsizing methods of DLG data,the relationship between DLG data downsizing methods and the downsizing rules,and the relationship between the downsizing rules and the city DLG data downsizing rule base.The main work is as follows:(1)Research and analyze the related methods of DLG drawdown based on the database layer,combine the national standard topographic map data specification and map data dictionary and other normative documents to study and analyze the drawdown rules of DLG data,and summarize the structural characteristics of the drawdown rules under different scales And the change rule of constraint conditions,the basic influencing factors of the map drawdown rule are analyzed.(2)According to the structural characteristics of the DLG drawdown rules,combined with the relevant requirements of comprehensive operators and constraints,summarize the DLG drawdown rules to obtain a universal DLG drawdown rule structure.Establish a comprehensive operator unit based on the DLG drawdown rule architecture,and conduct research on the collaborative processing of comprehensive operators suitable for DLG data production on the basis of the comprehensive operator unit,study the comprehensive application of drawdown rules,establish a database of urban DLG data drawdown rules,and implement drawdowns Systematic management and application of rules.(3)Developed on the basis of the Mapstore library integration platform to realize the city DLG data downsizing rule library,and based on the city DLG data downsizing rule library to conduct automated downsizing experiments from 1:5000 scale maps to1:10000 scale maps,and analyze the experimental results.The article establishes a database of urban DLG data reduction rules,proposes a comprehensive operator unit,and decomposes the DLG reduction rules from three main aspects: graphic constraints,semantic constraints and comprehensive algorithms,and integrates different functional comprehensive operators into a unified structure.The city DLG data downsizing rule library realizes the automatic downsizing processing of the city DLG data,and has completed the downsizing experiment for the DLG data.