面向自动综合的河系结构化模型研究

针对地图上河流的自动综合,建立了基于河段的河系结构化数据模型,该模型充分考虑了河段与河段、河段与面状水系要素之间的空间关系,以及河系河段的层次关系;建立了一种面向自动综合的河系结构化数据模型,模型包含了大量水系综合所需要的信息。基于上述数据模型,设计了一种方便快捷的河系结构化算法,该算法较好地克服了现有河系结构化算法只针对河流以及只适用于形态相对简单的河系的缺陷,较为全面地考虑了河系结构中出现的各种复杂问题,具有较强的实用性。     

面向自动综合的河系结构化模型研究

针对地图上河流的自动综合,建立了基于河段的河系结构化数据模型,该模型充分考虑了河段与河段、河段与面状水系要素之间的空间关系,以及河系河段的层次关系;建立了一种面向自动综合的河系结构化数据模型,模型包含了大量水系综合所需要的信息.基于上述数据模型,设计了一种方便快捷的河系结构化算法,该算法较好地克服了现有河系结构化算法只针对河流以及只适用于形态相对简单的河系的缺陷,较为全面地考虑了河系结构中出现的各种复杂问题,具有较强的实用性.     

双线河向单线河转换的一种改进算法

针对地图自动综合中双线河向单线河转换的问题,提出了一种改进算法.首先使用非约束中点法提取双线河中轴线,并基于中轴线对双线河进行分段;然后用小河段中轴线缓冲区检测小河段的空间图形冲突;最后依据制图规则解决空间图形冲突,并修正综合结果.     

我国华北地区水系表示中的几个新问题

水系是地图上最活跃的自然要素之一,其编绘质量直接影响到地图的质量。而水系表示的正确与否主要体现在河流符号的运用、河流宽度和形态的掌握,河流选取指标的确定和湖泊岸线的编绘等诸方面。近十年来,随着工农业生产的发展和自然环境的影响,华北地区地表水原在不断减少。地下水的过采、气温的升高、用水量的增加和植被的毁坏又加剧了河川径流量的减少,引起了该地区水系要素尤其是河流的一系列变化,主要有河宽的减小、河流     

基于遥感影像和矢量数据的水系变化检测

介绍了基于遥感影像和矢量数据的水系变化检测方法。根据矢量的拓扑结构,将水系分为主干河流、湖泊和支流水系网。对主干河流采用"模式分类、区域生长、形态学处理、边缘提取、缓冲区检测"的流程,对湖泊采用"区域生长、形态学处理、多边形面积相减"的处理,对支流水系网采用"金字塔分解和多尺度模板匹配、Ziplock Snakes模型优化、缓冲区检测"的策略。实验结果验证了上述方案的可行性。     

水系元胞自动机的设计与实现

水系元胞自动机模型是应用元胞自动机理论对水系的形成与发展的随机过程进行模拟的模型。本文使用DEM作为基础数据,针对水系元胞自动机模型的建模过程和模型结构,详细阐述了将其抽象为计算机中具体的数据模型,以及使用C#程序设计语言实现该模型对水系进行模拟的具体过程,模拟了南流江流域局部地区的水系发展过程,为元胞自动机与水文学研究的结合提供了参考。     

军交图数据库支持下线状要素的自动化简

本文主要内容包括线状要素形状化简的算法、线状要素几何上的合并——双线河合并为单线河,并对实验样图进行了分析。     

1∶250000水系要素综合缩编技术方法

针对国家空间数据基础设施建设的需求,本文介绍了适应于不同空间特征水系的河流选取、湖泊合并、毗邻等基本综合操作,并提取水系综合相关算法和技术思想,结合地形数据的基本特点及应用需求,给出了一套可行的1∶250 000水系综合实施策略。所研究的成果可应用于小比例尺地形数据的综合生产任务。     

不同DEM数据源的艾比湖流域仿真水系对比

针对干旱半干旱地区内陆河流域在仿真水系模拟方面研究较少和数据适用性的问题,该文提出利用SRTM3-DEM和ASTER-GDEM两种数据源对艾比湖流域进行仿真水系模拟和精度对比的研究。采用ArcGIS Hydrology模型分别对两种DEM进行水系模拟,通过多次设置参数和阈值,实现了不同水平分辨率和不同阈值河网水系的对比分析;然后利用Google Map河流数据和实测水系数据进行精度验证,同时采用"套河差"算法研究水系的差异。结果表明:SRTM3-DEM模拟的河网水系与实际水系更接近,吻合精度较高;DEM的坡度和水平分辨率对模拟水系的影响不大,但DEM的垂直精度对模拟水系的吻合精度起控制作用。本研究为艾比湖流域在水文方面的研究提供了一定的参照和依据。     

我国华北地区水系表示中的几个问题

水系是地图上最活跃的自然要素之一，其编绘质量直接影响到地图的质量。水系表示的正确与否主要体现在河流符号的运用、河流宽度和形态的掌握、河流选取指标的确定和湖泊岸线的编绘等诸方面。近十年来，随着工农业生产的发展和自然环境的影响，华北地区地表水     

河湖划界测量应用探讨——以聊城市河湖水利工程为例

河湖管理范围和水利工程管理与保护范围划界是进一步推动河湖长制从"有名"到"有实"转变的有效措施，由于各县区河湖及水利工程体量巨大、涉及面广、历史遗留问题复杂多样，该项工作开展难度较大。本文通过梳理分析河湖划界当前存在的难题，探讨利用无人机航测技术和实景三维展示等现代化测绘技术手段解决该难题的可行性，具有一定的参考借鉴意义。     

Robust river boundaries extraction of dammed lakes in mountain areas after Wenchuan Earthquake from high resolution SAR images combining local connectivity and ACM

River boundaries extraction from SAR imagery is valuable for flood monitoring and damage assessment. Several rivers, parts of which include dammed lakes caused by landslides and rock avalanches triggered by the 2008 Wenchuan Earthquake, were taken as a case study for robust extraction. In this paper, a novel state-of-the-art approach for automated river boundaries extraction using high resolution synthetic aperture radar (SAR) intensity imagery is presented. The key of our approach lies in the combined usage of local connectivity feature of the river and a region-based active contours model (ACM) in a variational level set framework to differentiate between river and the background. First, sub-patched intensity thresholding segmentation is applied to SAR imagery. Pixels with intensities below the threshold are selected as potential river pixels while the others are potential background pixels. Second, potential river pixels are divided into several connected regions, considering that the river is a big connected region, only relatively bigger regions with similar contrast value are retained as the regions of interest (ROI) while others are noise due to pixel-level decision approach in the first step or shadows due to mountains terrain. Third, the ROI and their contours are regarded as local region and the initial contours to refine the river boundaries, which are used to reduce the scene complexity of ACM and its sensitivity to initial situation, respectively. A novel ACM driven by local image fitting (LIF) energy is presented and used for river boundaries extraction for the first time, which is not only robust against inhomogeneity widely spread in SAR imagery but also can work with efficiency without the need of re-initialization during iteration compared to traditional ACM. The proposed approach was tested on numerous high resolution airborne SAR images containing connected rivers or dammed lakes obtained by Chinese domestic radar system after Wenchuan Earthquake. For the overall dataset, the average commission error, omission error and root mean squared error were 6.5%, 3.3%, and 0.51, respectively. The average computational time for 4000 by 4000 image size was 21 min using a PC-based MATLAB platform. Our experimental results demonstrate that the proposed approach is robust and effective.     

GIS中河网空间数据模型

河网通常是由多条河流组成的,河网的空间形态结构特征由各条河流的几何特征和河流之间的相互关系决定,为了完整表示河网的空间形态结构特征,本文提出了基于河网空间形态结构特征的河网空间数据模型,并阐述了该模型的建立、维护等方法。     

面向等高线与河流冲突处理的多约束移位方法

本文针对等高线与河流的不一致性问题,以移位等高线匹配河流为出发点,提出一种对每个特征点动态确定仿射变换模型进行移位的方法。该方法综合考虑移位角度比例、地形特征点相对位置、局部形态的保持和变换等因素,对各特征点实时计算其位移的角度、位置和缩放变化等约束建立其移位模型。实验结果表明,本文提出的方法能够较好地实现等高线到河流的一致性改正,可有效解决等高线与河流数据的空间匹配问题。     

天狼星无人机航测技术在河湖划界中的应用

由于河湖覆盖面广、线路长、体量大，同时历史遗留问题较多，采用常规测量手段存在诸多难题。本文结合具体工程案例，通过天狼星无人机航测技术手段，论证了新技术方案的可行性与有效性；阐述了天狼星免像控无人机在河湖划界工作中的优势和高精度航测成果一图多用的重要意义。本文方案对类似工程的开展具有一定的参考借鉴意义。     

Channel Pattern as Signature of Neotectonic Movements — A Case Study from Brahmaputra Valley in Assam

Spatial characteristies of drainage geometry of Brahmaputra river and its tributaries were studied based on visual interpretation of 1RS IB imagery (on 1:250,000 scale) and topographical maps of different periods. Observed features of drainage lines alongwith possible mechanism of their formation in terms of neotectouie adjustment are discussed It is inferred that selected stretches of Brahmaputra river viz. between Dibrugarh and Jorhat and between Guwahati and Goafpara may represent channels with active boundaries that have restrieted/controlled the width of sinuous lines of discharge of the river within the valley. Local tilting of ground, lying to the south-east of Brahmaputra river, between Noa Dihing and Burhi Dihing rivers, may explain some of the observed features of these drainage lines Movement along some lineaments in recent past has occurred. This inference is based on the evidence of adjustment of several drainage lines viz, Dihing. Burhi Dihing. Dikrang. and Mora Bhareh rivers and displacement of rocks of younger age.     

邯兖线跨黄河水准测量方法与实践

在水准测量的路线上,经过较宽的河流、湖泊或峡谷等地貌时会采用跨河水准测量作业方式。跨河水准测量是指为跨越超过一般水准测量视线长度的障碍物而采用特殊方法(倾斜螺旋法、经纬仪倾角法、光学测微法等)进行的水准测量。因此,采用什么样的技术手段和方法进行跨河水准测量仍是一个非常重要的课题。本文以邯兖线跨黄河一等水准测量工作为例,探讨其测量方法与工作技巧,以期为以后跨河水准测量工作的开展提供技术参考。     

数学形态学与拓扑约束支持的单条河流骨架线提取

为解决当前遥感手段提取河流骨架线自动化程度不高、精度有限、易发生断裂等问题,提出一种基于数学形态学与拓扑约束理论的完整单条河流骨架线自动化提取方法。该法综合利用归一化水体指数(NDWI)和数学形态学方法提取遥感影像中的河流及河流初始骨架线;从河流初始骨架线二值图中获取断点,并自动计算膨胀系数,利用局部膨胀细化法进行连接;结合拓扑约束,利用初始骨架线对连接线进行去伪操作。结果表明,该方法能有效解决细小、易发生断裂的单条河流的完整骨架线自动提取的难题。     

Detection and correction of inconsistencies between river networks and contour data by spatial constraint knowledge

In the representation of topographic data, the distribution of hydrographic networks should be constrained by the contour model’s landform features. During the integration of topographic databases, however, spatial conflicts may destroy these constraints, generating inconsistencies. This study presents a method to detect and correct inconsistencies between river networks and contour data by spatial knowledge. First, structured terrain features are extracted from the contour-based geometric representation and matching relationships between rivers and contours are constructed based on spatial knowledge of the distribution of rivers and talwegs. We then propose a distance metric for measuring differences and identifying inconsistencies between the matched river and contour features. Three correction approaches are provided for different inconsistency situations, including river adjustment referenced to the contour, contour adjustment referenced to the river and adjustment of both river and contour to middle positions. We apply the proposed method to the integration and maintenance of national topographic infrastructure in order to demonstrate its effectiveness.