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Isoline map is extensively used in science field and productive practice, such as oil exploration, geography and environmental monitoring, so it has important meaning and application value to study isoline drawing technology and software development. With the development of science and technology, isoline drawing technology experienced the great-leap-forward development from hand-drawn stage to computer automatic drawing stage, became an important context for the study in digital visualization field. This thesis taking isoline drawing as the research subject, introduced the common methods used to draw isoline and rendering process currently, analysed the limitation of traditional isoline drawing method. On the one hand intensively study isoline rapid drawing technology, and on the other hand make it apply to productive practice by way of complete isoline drawing system.Firstly, aiming at the low search efficiency to unevenly distributed sampled data of the traditional regular rectangle grid method, presented a multiple grid division rapid search algorithm. Above of all,it carried on multiple grid division of sampled data, and distributed the sampled data to each grid cell,created index structure for grid cell, and then rapid search algorithm fixed on grid cell by computing grid coordinate and accessed to the data of the grid cell.If the amount of data is not enough to, it extendly carried on searching the grid cell which is around to this center grid cell, until the amount of getted data was sufficient.Then analyse time and space efficiency of rapid search algorithm, discussed the tow key factors which affected this algorithm, and test and validate the method of identifying key factors, improved the efficiency of the algorithm.Secondly, exploited the geological mapping system at Visual Studio 2008 platform use QT labriry. Based on in-depth understanding of use cases and industry characteristics, this paper designed and achieved the general frame and each functional modules of system, core modules include isoline drawing autogeneration module, graphic layer manage module, graphic item manage module,data manage module,general editor module and so on, and system achieved a multiple grid division rapid search algorithm which was presented in this paper, and soline labeling method based on tangential slope approximation, the para-curve WAA weighted average algorithm, isoline filling method based on grid. The whole of development process give full consideration to the software compatibility, scalability and interactivity, in strict accordance with the software development process, experienced needs analysis, detailed design, coding, debugging operation and maintenance several stage, each stage has formed the detailed documentsLastly, the test of geological mapping system in oil exploration generating practice shows that system can quickly draw the geological map of the isoline map and structural map, accuracy of the generated isoline meet the production requirements, also provides researchers with a convenient editing map function.
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