A Study on Generalization of Linear Features on Topographic Maps
|關鍵字:||地圖縮編;地形圖;線形地物;map generalization;topographic maps;linear features|
The thesis concentrates on the map generalization of roads and rivers to reduce manual operation and improve the automation and consistent of map production. The fundamental operation of generalization is linear simplification and smoothing. A shape simplification method on topographic map was presented in this thesis. The method is superior to visual method and Douglas Peucker method according to the evaluation of road networks, administrative districts and contour lines. There are three steps were included in the processing of road generalization that are data preprocessing, generalization of road networks and linear simplification and smoothing. A route searching method was proposed to automatically identify the contexts of road networks and establish the attribute of routes in data preprocessing. The metrology of road networks generalization used not only adopts the rule of route length but also develops a route connected detection method to ensure the logical consistent. Road classes and roads selection in different district were also considered in the rules of generalization. The procedures of river generalization were similar to road generalization including data preprocessing, generalization of river networks and linear simplification and smoothing. Constraint delaunay triangulations was applied to automatically identify branches and center lines of rivers in data preprocessing. The data structure was also conducted to design the aggregation of rivers in generalization of river networks to improve automation. The proposed methods in this thesis generalized roads and rivers to scale 1:50,000 and 1:100,000. An evaluation was applied to compare the generalized results with manual compilation.
|Appears in Collections:||Thesis|