【作者】 黄丽娜；

【导师】 费立凡；

【作者基本信息】 武汉大学 ， 地图学与地理信息系统， 2010， 博士

【摘要】 地貌综合是地图综合中的一个重要组成部分,也是其中的难点之一。地貌客观存在于三维空间之中,其形态复杂、表现形式多样,因此其数据的表达形式也多种多样,这就使得地貌综合成为最复杂的信息变换,具有高度的挑战性。本文从三维信息承载的角度,以全新的思维方式重新审视了地貌综合问题。并提出应基于对地貌三维信息的理解,将地貌建模的概念延伸至广义DEM形态,以此保证不同形式的DEM在综合前后都能获得表达效果上的统一。地貌信息的概念也同时具有广义性,因此紧贴地面的、三维形态的水流路径也同样可看作是地貌信息的子集。本文将水系的地形信息纳入广义DEM范畴之中,创新性的提出了地貌与水系要素的一体化综合思想；通过加强地表决定塑形的特征特征,保证了地图综合的真实还原。这一措施,在实践中也可以有效的解决地貌和水系化简后的冲突问题,因此具有非常重要的现实意义。本文的具体研究内容包括：(1)明确了数字环境下地图综合问题的时代内涵和重要意义,分析了地貌综合的挑战和新特点,总结了国内外地貌综合研究进展,并着重探讨了地貌综合的理论研究成果和现有算法。(2)通过对地貌形态的三维连续性、复杂多样性、空间邻近性和地貌单元的不确定性的阐述,讨论了对地貌信息的理解以及地貌形态的DEM建模方式。DEM是关于地貌信息的模型,也是诠释地貌特征的必要途径。在介绍了现有DEM的结构形态和常见范式基础之上,本文提出如下观点：同一地区不同形式的DEM本质上是地表三维形态的多态表达,理想状态下它们应是一组“同质异构”体。由此提出了广义DEM的基本内涵：①虽然DEM具有多种表达形式,但是描述同一地貌信息的不同形式的DEM之间应该是等价的：②不规则分布的离散点是所有DEM形式之中的最一般形式,任何其他形式的DEM都可看作是它的外延表述方式；③因此,一旦这种最一般形式的DEM被正确综合,那么同一地貌区域的任何其它形式DEM都可以被综合到相同程度下。(3)从广义DEM的角度,提出地貌综合应将地貌对象看作是地表高程点的信息集合体。因此,本文在对各种地貌三维综合的约束条件以及现有的DEM综合概念框架进行充分讨论的基础上,并以此提出了基于广义DEM的地貌综合模型。该模型包括四个内容：①地形特征点集的三维选取,②综合过程中地形要素的地形约束,③综合程度的自动控制和④综合结果的质量评价。本模型特别提出应将分布于地表的水系要素看作是地貌综合过程中的地形约束,水流路径的地形起伏是对地貌三维综合信息补充,并对地貌形态的化简起控制作用。(4)建立了基于3DDP的地貌综合算法体系。本文重点阐述了3DDP算法提取地貌特征点的实现机制。在此基础上,从高程点的空间邻近特性出发,深入研究3DDP算法对各种具体DEM的优化方法,提出了基于Grid DEM的扫描排序法、基于等高线DEM的线式排序法以及全局孤独指数加权计算伪点面距。然后针对单一原点选取地形特征点时出现的“灯下黑”现象,提出了基于视觉辨析的特征点选取模型——趋势面模型和多视角模型。并以实际丘陵地貌和高山地貌样区为例进行实验,分析了3DDP改进算法对不同类型地貌的地形特征点提取的适用性。(5)深入探讨了地貌与水系要素在现实世界中和谐的空间关系,将从大比例尺到小比例尺的制图综合中地貌与河系的组合变化归纳为三种状态：“有水有谷”、“无水有谷”和“无水无谷”。分析了现阶段在自动制图综合中由于分要素综合而产生的两者之间不协调套合现象的根源所在,从地表流水的物理特性与地表三维特征的密切联系出发,将水流路径上的高程点也纳入广义DEM的范畴中来,提出了“地貌水系一体化”的制图综合思想。基于地貌三维综合模型,以树状河系为例,探讨了采用3DDP算法实现地貌与水系一体制图综合的具体流程与实现技术。实验表明,从三维角度对地貌与水系的特征点进行一体化提取,地貌与水系的空间形态既能被合理的化简,两种要素综合结果的图形表达仍然能够保持其相互之间的和谐关系,具有良好的制图效果。(6)就综合程度的自动控制和综合结果的评价两个问题进行了初步探讨。其中,针对第一个问题提出了自动控制综合程度的智能阻尼振荡法,即：通过对数据量的压缩和地貌信息量的压缩两重迭代自动调整综合阈值,从而达到预期综合程度。针对目前地貌综合结果质量的评判的主观性及难以定量化问题,本文从地貌综合的约束条件出发,提出了地貌综合评价的模型框架,包括地形精度评价、地形描述评价、地形逻辑评价、地形典型化评价和地形总体保真性评价,为后续的研究提供了思路。更多还原

【Abstract】 Relief generalization is one of the most important parts in cartography. Relief exists in the real three dimension world, it is complexity and polymorphism makes its digitalization worked out as multiple products. Relief generalization is full of challenges.In this paper, we re-examine the issue of relief generalization in the viewpoint of 3D information carrier inside relief. Thus we extend all the relief modeling conception to general DEM. The general DEM is expected to unify the different forms of DEM which always behavior different after the operations of relief generalization. The general DEM is also compliant to the composition of relief information. The river systems wandering behind the ground can also be regarded to be part of terrain information. In this paper we just adopt the concept and innovatively put forward the proposal of the integrated generalization of relief and river systems, which is meaningful for settle the problem of morphologic conflicts between the generalization of relief and generalization of water system.This paper specifically in the follow six import researches:(1) The paper clarified the meaning and significance of the study, analyzed the challenges and new features of relief generalization, summarized the progress of this research field and focused on the results of the theoretical researches and the existing algorithms.(2) The paper analyzed the features of relief including the morphology three-dimensional topographic continuity, the complexity, the diversity, the spatial proximity and the uncertainty of its elements. Then it discussed modeling methods of current DEM. DEM is a model of information about relief, and also has the essential means for interpretation the geomorphologic features. So, this paper raises the point: Different DEM forms are only multi-state expression of the same three dimensional shape of the earth surface, under ideal conditions they should be a set of "same Heterogeneous quality" stuff. Thus, we put forward the concepts of the general DEM: (i) the DEMs expressed in varied forms should be equivalent in nature; (ii) irregular distribution of discrete points is the most general form, any other form of DEM can be looked as its special cases; (iii) When the general form of DEM is correctly generalized, any other form of DEM can also be generalized with the same precise.(3) In the viewpoint of "General", the DEM information should include all the elevation point. With start point, after discussing the three-dimensional relief generalization constraints and the existing DEM generalization conceptual framework, this paper proposed a model for the relief generalization based general DEM. The model includes four elements:(ⅰ) three dimensional topographic feature point selection, (ⅱ) the terrain constraints analysis, (ⅲ) the degree of automation and (ⅳ) the qualitative evaluation of the generalization results. The model particularly emphasized that the water system winding on the earth surface should be regarded as the constraint for the process of relief generalization. Flow path is a kind of important compensation to the three-dimensional relief information and can partly control the final result of relief morpho-simplification.(4) Based on the expatiation of implement mechanism of 3DDP algorithm for the feature points’extraction, we constituted the 3DDP algorithm systems for the relief generalization. Making use of the spatial approximation relation between the elevations, a series of optimization methods were proposed for some specific DEM, such as the scanning sorting method for the Grid DEM, the line wise sorting for the contour DEM, and global loneliness index for weight pseudo point-plane distance calculation. Furthermore, Trend plane model and the multi-view model were prompt based on the visual selection. With a case study, we successfully proved the well feasibility of 3DDP algorithms.(5) The harmonic spatial relations between the relief and the water system in the real world were discussed deeply. Their integrated combinations were summarized in three states:"river exists and so is the valley", "river vanish but valley exist" and "river vanish and so is the valley". Based on the semantic affinity of the stream physical characters and the 3D feature of the earth surface, the elevation points on the flow pathway can be viewed as the elevation points, namely a kind of general DEM. Therefore, the basic idea of integrated generalization of relief and water systems is brought forward. Based on the 3D relief generalization model, take the dendriform water systems for example; we advanced the framework integrated cartographic generalization of the relief and water system using 3DDP algorithm. The experiments show that this integrated generalization can simplify the spatial configuration of both relief form and the water systems, while keeping their harmonious relations.(6) The automated control on the generalization degree and the evaluation of the generalization results are two important portions in the relief generalization process. For the first issues, we advanced a new method named intelligent damping oscillation, which can automatically adjust the generalization threshold by twofold iterative level, one is the amount of data compression and the other is the amount of relief information. For the second issue, whereas the quality assessment of the results of the relief generalization is obviously subjective at present, we had some preliminary discussions on it. The quality assessment of the relief generalization should be based on the same abstracted level, and the better results relief should be the one which more approaches the original physiognomy. we also proposed the methods for the quantification of the relief information and the generalization results for the further study.更多还原