河流水流泥沙数值模拟结果等值线绘制技术研究

Study on contour-map technology of numerical simulation of flow and sediment transport in river

文章在回顾以往等值线生成算法的基础上,综合不同等值线绘制算法的优点,探求了新的实现河道地形、泥沙冲淤等值线绘制算法,使其更具有编程可实现性,并在MS.NET框架下编制程序予以实现。程序采用坐标变换技术保证显示图形的无级缩放,具有极大的灵活性,可以满足局部详细信息显示的要求;采用多种编程技巧和程序优化措施,如线段拼合技术、写内存技术、多线程技术、双缓存显示技术等,保证等值线的快速生成和即时显示;采用二次贝塞尔曲线平滑等值线,并合理地对等值线进行标注,从而完整地实现了等值线绘制的全部内容。通过实际工程应用并与商业软件对比表明,程序的等值线生成快速、绘制准确美观、标注合理,达到了商业化软件的精度,能够满足要求。

Based on the review of isoline generating algorithms, advantages of different methods were colligated. An algorithm of contour-map of river terrain and sediment erosion and deposition was discussed in this paper. The software was programmed on the basis of MS. NET framework to process contour-map. Coordinate transformation technology was adopted to ensure stepless enlarging or lessening, so the software has enormous flexibility and can satisfy the requirement of the local detail information display. Many kinds of programming skill and optimization were used to assure the fast contour-map generation and real-time display such as line segments rean-anged, EMS memory writing, multi-threading and graphics buffer technologies and so on. Quadratic Bezier curve is used in isoclines smoothing and contour markers are also reasonably, so all things have been done for isograms map. Through the actual engineering application and compared with commercial software, it shows that the software has a fast, accurate rendering in isograms generating, and the markers are reasonable, it has the same accuracy with commercial software and satisfies the requirements of the same engineering.