River Automatically Integrated Technology And Software Development

Map generalization has been an active question in map cartography and GIS field over years. Under the digital technique environment, the map generalization turns to special geo-feature oriented generalization research from general geometry oriented generalization research on model algorithm, then map generalization has different semantic oriented essential generalization, this paper which emphases on the rivers factor generalization fits the process. Not only the rivers generalization realize need to appraise rivers' quantity and the quality character, but must take into consideration the rivers in the river is the position which and other related structural feature in the structure locates. Therefore this paper has analyzed the primary coverage and the characteristic of rivers generalization, and has designed a kind according to the allotment method of the selection index sign of subsidiary current amount difference.This paper mainly centers on river generalization and researches with different levels—the theory, the method, the technique and algorithm and so on. The rivers generalization method uses structures, selection and simplification. At last, a through to analyzes and evaluates the experiment data of the length selection method, the length and the spacing selection method and the level selection method, gains a satisfactory generalization result. The paper main researches work as follows:1. Researches on domestic and international of map generalization, and analyzes the challenge face by it. In the meantime, researches on the map generalization of concept, classified, the method, the impact factor and comprehensive principle of the river generalization.2.Based on the river system structure, this paper propose a new method, to generalize dendritic drainages while maintaining the density differences between sub-drainages, which is based on the level division of the number of retained rivers in river trees. The level generalization is executed in four steps. First step, the river tree is constructed, and the quantity of tributaries for each river is counted. Second step, the quantity of rivers to be retained in the generalized version is computed according to the Square Root Law. Third step, calculates the length of retained rivers which is the most and counts outfall spacing of the same that level and orientation. Finally, the number of retention is divided among all of the drainages according to the number of their tributaries, the mainstream of a drainage with big length and spacing is selected, and the allocation and selection are recursively executed in the lower layer until the number of the selected rivers reaches the limit of the drainage.3.The method is implemented as ArcGIS9.2 Environment and ,ArcEngine as tool and C# as language. Experimental results are compared with the selection by length ,by length and spacing and by levels. A case study of rivers generalization shows that the method created acceptable results, and the characteristic of dendritic drainages structure and the density differences among rivers are maintained effectively.