小比例尺地貌晕渲图生成方法研究与实现

发布时间：2019-01-08 08:26

【摘要】：地貌是地理信息中最基本的要素之一,晕渲图是最常用、最直观的一种地貌表示方式。晕渲图的绘制主要依赖于三个基本原理：几何光学原理、半色调原理、空中透视原理。随着科技的发展,计算机自动地貌晕渲逐渐取代了传统的手工地貌晕渲,通过光照模型计算地表某一点的灰度值,得到明暗对比的地貌起伏变化。其在数据准确性、成图速度方面具有非常大的优势,但在视觉效果方面较手工绘制的晕渲图仍有很大差距。如今,有多种改进方案应用于计算机自动地貌晕渲,比如：调整光源、增大高程垂直比例等。在制作小比例尺地貌晕渲图时,需要对DEM数据进一步处理。由DEM数据生成的地貌晕渲图通常有很多干扰的地形细节,影响晕渲图的整体效果,这种情况在小比例尺地貌晕渲图中更加明显。现有的基于重采样、基于各项异性滤波等处理DEM数据的方法存在着一些不足。本文提出一种新的去除干扰细节的小比例尺地貌晕渲图生成方法,该方法将DEM数据整体滤波后,借助曲率属性对特征地形进行夸大或加深处理,再将处理后的数据生成晕渲图。实验表明：该方法能够有效的移除了破碎的地形细节,同时保护特征地形,生成的晕渲图整体效果很好。
[Abstract]:Geomorphology is one of the most basic elements in geographical information, and shading map is the most commonly used and intuitionistic geomorphological representation. The drawing of shading map mainly depends on three basic principles: geometric optics principle, halftone principle and aerial perspective principle. With the development of science and technology, the computer automatic relief shading has gradually replaced the traditional manual relief shading, and the light model is used to calculate the gray value of a certain point on the surface, and the geomorphological fluctuation of the contrast between light and shade is obtained. It has great advantages in data accuracy and mapping speed, but there is still a big gap in visual effect compared with hand-drawn shading map. Nowadays, there are many improved schemes for automatic relief shading, such as adjusting light source, increasing vertical ratio of elevation and so on. The DEM data need to be further processed when making the small scale relief shading map. The relief shading map generated by DEM data usually has a lot of disturbed terrain details, which affects the overall effect of the shading map, which is more obvious in the small scale relief shading map. The existing methods for processing DEM data based on resampling and heterosexual filtering have some shortcomings. In this paper, a new method for generating small scale relief shading map is proposed. After filtering the DEM data as a whole, the shading map is generated by exaggerating or deepening the feature terrain with the help of curvature attributes. Experiments show that the method can effectively remove the detail of the broken terrain and protect the feature terrain, and the overall effect of the generated shading map is very good.
【学位授予单位】：北京林业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：P285.1;TP391.41

【参考文献】