Study On Line Feature Generalization And Its Data Processing

In the paper, in view of multi-mapping-scale line feature generalization problem in cartography,GIS cartographic spatial data uncertainty and several line feature generalization algorithms,such as Li-Openshaw generalization algorithm,direct generalization algorithm, indirect generalization algorithm and curve fit algorithm. GIS spatial data uncertainty and the whole data processing are applied in map generalization data processing .According to the feature of the original data and the generahzated and the need of problems handling,kinds of condition equations of generalization data processing including equal arc length condition equation ,area condition equation and end vertexes identical equation and fix point condition equation is discussed. Take example by the administrative border data of a villages and towns in the Shandong province,according to kinds of generalization algorithms we carry out calculation and test and verify the line generalization effect and data processing effect and practicability and rationality on the calculation schemes of kinds of condition equations, received data are content with precision.And such a conclusion is drawn that the effect of direct generalization algorithm and indirect generalization algorithm is better,especially after lines are generahzated by direct generalization algorithm,the quantity of data are reduced largely.Kinds of elliptical condition equations on data processing are discussed, including right-angle coordinate X-Parameters(X,Y) and elliptiacal X-Parameters (B,L).According to the measured data to carry out calculation, elliptical data after being processed are content with precision.And condition equations on data processing based on fractal dim are discussed, take example by the administrative border data ,according to the condition equations based on fractal dim and calculating data,the condition adjustment calculation scheme can certify data precision after and before generalization.