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等高线是地形图的重要要素,通过等高线的高程、空间或层次关系可以进行各种地形地貌的判读。等高线的层次关系通常利用等高线树来表达,本文使用了AcrObjects构建等高线树,并在等高线树的基础上,提出了一种自动判别洼地曲线的方法。 相似文献
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一、引言
等高线是其它地形表示方法的几何基础,一组有一定间隔的等高线的组合可以用来较好地反映地面的起伏形态和切割程度。利用等高线数据来构建DEM是DEM数据生产的重要方式之一,不仅可以完整地表现地形的整体特征,还能保留某些复杂区域的地形特征。 相似文献
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提出了一种能够通过具有实际意义的参数控制等高线平滑程度,通过等高线平滑可以控制等高线细节的表达程度的方法,能够完成不同尺度下等高线的简化;算法通过结合曲线平滑和迭代最大残差抑制方法,完成等高线平滑程度控制,此时全体高程点平面位移均低于给定平滑容差.首先通过自适应算法选取最大平滑因子,对全体高程点进行平滑处理,选择点位位移最大高程点进行局部处理,以一定倍率逐渐减小平滑因子,使得该点点位位移低于给定平滑容差;不断重复该过程,直到全体高程点点位位移均低于给定平滑容差,从而完成等高线平滑程度的控制.经实验验证,等高线平滑后曲线曲率更小,曲率变化更加均匀,且等高线精度能够通过参数进行控制. 相似文献
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等高线高程注记的常用方法有两种,一是人工注记,二是通过编程实现自动注记,人工注记过于繁琐,严重降低了工作效率,编程注记对作业人员的编程能力要求较高.为了解决这两个问题,提出了一种新的等高线高程注记方法,即通过ArcGIS和AutoCAD的结合进行等高线高程的批量注记.由于该方法完全通过软件实现无需编程,因而它的适用范围更加广泛.现以某区域等高线为例,对提出的方法进行了验证,结果表明该方法可以对等高线高程进行正确注记,基本满足地形图等高线注记的要求. 相似文献
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本文研究了一种利用栅格DEM和地形特征数据,直接计算等高点并生成数字等高线的方法,对于采用栅格数据输出设备输出等高线而言,这种方法可以免去矢一栅等高转换等计算,初步实验表明,这种方法给出的等高线地貌显示良好。 相似文献
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基于Delaunay三角网的等高线树生成方法 总被引:1,自引:1,他引:0
研究如何利用Delaunay三角网构建等高线树,提出一种新的等高线树生成方法。该方法充分利用Delaunay三角网在领域分析中的优势,通过两次利用Delaunay三角网来判明等高线的空间关系进而达到统一被图廓截断的等高线以生成等高线树的目的。本文将等高线作为约束边构建约束型Delaunay三角网,利用Delaunay三角网查找具有邻接关系的等高线,在此基础上结合邻近等高线的高程关系判明、识别,最终统一被截断的等高线;然后对统一后的等高线再次利用Delaunay三角网查找具有邻接关系的等高线对,利用等高线对的高程关系判断出其为父子关系或兄弟关系,据此将等高线插入到相应的位置,逐步生长成等高线树。同时给出了基于Delaunay三角网的等高线树生成方法的算法设计及试验结果。 相似文献
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This paper discusses the rules representing relief with contour lines and methods for automatically constructing relation of contour lines.Meanwhile,the improvement of existent methods for extracting the topographic characteristic points and lines is described.On the basis of this analysis,we propose a series of practicable progressive graphic simplification ideas of contour lines and concrete algorithms for the exception's handling.In this way,graphic generalizations of contour lines at different scales are integrated into one model that is convenient to implement,and in which contour lines' intersection in generalization can be controlled. 相似文献
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This paper discusses the rules representing relief with contour lines and methods for automatically constructing relation of contour lines. Mean-while, the improvement of existent methods for extracting the topographic characteristic points and lines is described. On the basis of this analysis, we propose a series of practicable progressive graphic simplification ideas of contour lines and concrete algorithms for the exception’s handling. In this way, graphic generalizations of contour lines at different scales are integrated into one model that is convenient to implement, and in which contour lines’ intersection in generalization can be controlled. 相似文献
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FEI Lifan 《地球空间信息科学学报》2013,16(1):85-95
ABSTRACT This paper analyzes the advantages and disadvantages of two technical lines for automatic group generalization of contour lines. The author suggests that it is possible to get faster and better generalization results if we simulate the intelligence of human experts in program designing, retrieve geomorphological structural information using the input data of 2-D contour lines and derive and output the generalized 2-D results directly. 相似文献
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This paper analyzes the advantages and disadvantages of two techni-cal lines for automatic group generalization of contour lines.The author suggeststhat it is possible to get faster and better generalization results if we simulate theintelligence of human experts in program designing,retrieve geomorphologicalstructural information using the input data of 2-D contour lines and derive andoutput the generalied 2-D results directly. 相似文献
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等高线的空间关系规则和渐进式图形简化方法 总被引:6,自引:0,他引:6
详细讨论了等高线表达地形的规则和以此为基础自动建立等高线关系的方法,对地形特征点、线的提取改进了已有较成熟的方法,建立了一套实用的等高线图形简化的渐进式方法,并对其特殊情况的处理提 出了具体的算法。这种方法把不同比例尺跨度的等高线图形综合融为一体,易于实现,等高线图形简化时的等高线相交可在综合过程中控制。 相似文献
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复杂等高线自动综合是计算机辅助制图领域中一项重要且难度较大的任务。本文根据分形理论的基本原理,提出了一种基于量化等高线形状结构特征的复杂等高线自动综合的新方法。研究和实验表明,该方法充分顾及了地貌形态特征,能够对等高线图形进行客观、有效地概括。 相似文献
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将等高线看作是由高程点以特定形式组织得到的空间三维线段,采用3维Douglas-Peucker算法从三维空间提取等高线上的主要特征点。根据等高线数据特点,对该算法进行等高线综合的几种方案进行实验讨论。实验结果和运算速度表明,采用3维Douglas-Peucker算法综合等高线具有广阔的研究前景。 相似文献
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The contour line is one of the basic elements of a topographic map. Existing contour line simplification methods are generally applied to maps without topological errors. However, contour lines acquired from a digital elevation model (DEM) may contain topological errors before simplification. Targeted at contour lines with topological errors, a progressive simplification method based on the two‐level Bellman–Ford algorithm is proposed in this study. Simplified contour lines and elevation error bands were extracted from the DEM. The contour lines of the elevation error bands were initially simplified with the Bellman–Ford (BF) algorithm. The contour lines were then segmented using the vertices of the initial simplification result and connected curves with the same bending direction were merged into a new curve. Subsequently, various directed graphs of the merged curves were constructed and a second simplification was made using the BF algorithm. Finally, the simplification result was selected based on the similarity between several simplification results and adjacent contour lines. The experimental results indicate that the main shapes of the contour groups can be maintained with this method and original topological errors are resolved. 相似文献