基于DEM数据的北天山地貌形态分析

基于SRTM3-DEM数据,运用GIS空间分析技术,通过面积-高度积分、地形高程(平均高程、最大高程、最小高程)、地势起伏度及地形剖面线方法,对北天山的地貌特征进行了初步分析。结果表明,北天山山势险峻并且呈NW-SE走向,显示天山受南北向水平挤压隆升作用。近S形的面积-高度曲线、偏高的面积高度积分值表明北天山地区处于构造活跃时期,地貌发育属壮年期的早期阶段。地形高程剖面线揭示了北天山存在3级夷平面地貌特征,地势起伏度变化幅度最大地区则是受陆内挤压构造应力影响地形抬升最强的地区。     

基于ArcView剖面图的绘制——以兴国县龙岗镇为例

地形剖面图在现代生产和科研方面都有着广泛的应用,地形剖面图能直观地描述沿特定方向的地形起伏变化,在地形地貌分析中具有重要的作用,在实际的地貌分析中剖面图能准确地反映出高程变化的统计特征,有助于地形与地貌之间空间关系的提取和分析。本文以江西省兴国县龙岗镇为例,通过对相关数据的采集分析处理建立该镇的DEM,利用ArcView软件实现剖面图的自动绘制,在绘制的剖面图上可以很直观地看出龙岗镇的地形为西北部和东南部地势较高而中间部分地势较为平坦。     

基于 SRTM DEM 的祁连山自然保护区地形特征研究

基于研究区的 SRTM DEM 模型,应用 ArcGIS10.5 空间分析模块及 Excel、SPSS 数据统计分 析功能,采用均值变点分析法确定地形起伏度的邻域分析最佳统计单元;提取了研究区高程、地形 起伏度、地形坡度、地表粗糙度和地表切割度 5 个地形因子,以分析研究区的地形特征。结果表明： 研究区地形起伏度最佳统计单元为 11 像元×11 像元（0.98 km²）,地形起伏度为 0～1 216 m。研究区 包含 13 种地貌类型,87.28%的区域为中海拔,中海拔平原、台地、丘陵为主要地貌类型。走廊南山、 冷龙岭、乌鞘岭和龙首山地平行分布,台地、丘陵穿插其中,地形复杂。研究结果为进一步探索自 然保护区的生态保护、开发利用等具体问题提供了基础数据支持。     

祁连山东段庄浪河流域地貌特征及其构造指示意义

晚新生代以来,青藏高原北东向扩展,致使祁连山地区遭受了强烈的构造隆升,造就了祁连山地区复杂的构造格局和急剧变化的构造地貌,其典型水系流域地貌特征揭示了该地区的新构造活动和地貌演化过程。庄浪河流域位于祁连山东段,作为青藏高原北东向扩展的前缘地区,庄浪河流域的地貌参数对构造活动非常敏感,提取庄浪河流域的地貌信息,有助于揭示祁连山东段庄浪河流域地貌对构造活动的响应,及系统探讨该区地貌发育特征及其所蕴含的构造意义。庄浪河流域内及边缘发育有庄浪河断裂、天祝盆地南缘断裂、疙瘩沟隐伏断裂以及金强河-毛毛山-老虎山断裂。晚新生代以来,这些断裂仍在活动,并且控制着流域内的构造变形、山体隆升和河流水系地貌发育。本研究采用ALOS DEM 12.5 m数据,基于ArcGIS空间分析技术,通过高程条带剖面、河流坡降指标体系（K,SL,SL/K）和Hack剖面、面积-高程积分值（HI）和积分曲线（HC）等方法,对庄浪河流域地貌特征进行了初步分析。结果表明,庄浪河地区地形起伏由北西向南东递减,构造活动存在东西分异的规律;庄浪河流域内部K值、SL、SL/K、HI值西侧高于东侧,Hack剖面西侧相比东侧上凸更明显;H...     

基于GIS的关中-天水经济区地形起伏度与人口分布研究

地形起伏度作为影响人口分布的重要因素之一,是人居环境自然评价的一个重要指标,在小尺度人居环境自然评价方面也具有较高的准确性和实际应用价值。基于关中-天水经济区栅格数字高程模型,采用窗口分析等方法,利用ArcGIS软件空间分析模块中的邻域分析,提取了基于栅格尺度的关中-天水经济区地形起伏度,并从比例结构、空间分布和高度特征3个方面系统分析了关中-天水经济区地形起伏度的分布规律及其与人口分布的相关性。研究结果为:①关中-天水经济区的地形起伏度以中低值为主,地形起伏度小于2.4的区域占总面积的96.66%,其中平地比例占总体的32.4%;地形起伏度越高的地区,平地比例越低,反之亦然。②关中-天水经济区的地形起伏度呈现南北高中间低的空间格局,最高值为宝鸡市太白县,最低值为关中平原;经度上的变化规律不是很明显,纬度上的地形起伏度无论从南到北还是从北到南都是先下降后增高的。③随着海拔高度的增加,地形起伏度呈现逐渐升高趋势,但变化幅度不大。④地形起伏度对区域人口分布有较强的影响,关中-天水经济区近90%的人口居住在地形起伏度小于1.5的地区,人口密度与地形起伏度的曲线拟合度非常高。     

青藏高原地形起伏度及其地理意义

地形起伏度是区域人居环境适宜性与资源环境承载力的关键评价指标之一。当前有关其最佳评价窗口、及其与海拔—相对高差的相互关系仍缺乏深入研究,进而影响该指标对区域地形起伏的有效表征。客观认识青藏高原地形起伏度有助于促进其国家生态安全屏障建设与区域绿色发展。以先进星载热发射和反射辐射仪全球数字高程模型（ASTER GDEM, 30 m）地形数据（V2）为基础,本文利用均值变点分析法确定了青藏高原地形起伏度评价的最佳分析窗口,基于地形起伏度模型（RDLS）研制了青藏高原首套30 m地形起伏度专题图,据此分析了地形起伏度与海拔、相对高差的相互关系,并界定了地形起伏度对区域地形起伏状况的有效表征。主要结果/结论包括：① 基于GDEM的青藏高原地形起伏度评价最佳窗口为41×41个像元的矩形邻域,对应面积约为1.51 km²,均值变点分析表明区域地形起伏度评价最佳窗口有其唯一性。② 青藏高原地形起伏度均值约为5.06,超3/5区域地形起伏度介于4.5~5.7之间;整体上,青藏高原地形起伏程度由其东北部向西南部、西部递增,仅在柴达木盆地、藏南谷地以及河湟谷地出现低起伏地貌特征。且地表起伏在不同纬度剖面变化较为一致（沿山脉走向）,但不同经度剖面起伏层次错落（横切山脉走向）。③ 相关性分析表明不同地形起伏度分别对应不同平均海拔、不同相对高差的地貌单元。青藏高原地形起伏度经纬向剖面分析表明,该区由东部的低山稳步爬升,山体经历骤然爬升（即地表起伏特征剧烈）后形成以极高山为主的有序错落起伏（喜马拉雅山脉）。     

基于低空摄影高精度数字高程模型(DEM)的风沙草滩特征及稳定性评价

基于无人机低空摄影测量获取到的高分辨率数字正射影像图/数字高程模型（DOM/DEM）,选取榆林榆阳区岔河则乡附近一片较为典型的风沙草滩为研究区,分别对沙丘地形因子（坡度、地形起伏度、地表粗糙度、剖面曲率）、斑块形状指数及植被覆盖度进行提取并构建稳定性评价体系,然后利用GIS空间分析功能对该区域内的沙丘稳定性进行了评价。结果表明：（1）无人机航测以便捷高效的特点,可生成高精度地形数据并实现小尺度沙丘地形特征提取;（2）在人工飞播固沙和风沙缓慢侵蚀的双重作用下,研究区已体现出较为稳定的风沙草滩区特有地貌环境特征;（3）该区域已经拥有一定程度的抵抗力稳定性,但不具备恢复力稳定性。     

基于GIS和遥感的中国城市分布与自然环境关系的定量研究

利用ArcGIS10、ENVI4.5、Visual FoxPro6.0等软件,采用空间分析技术手段,定量分析了中国655个建制城市的空间分布与河流、植被、地形起伏度、高程4种自然环境因素的关系,结论如下:①城市对水的依赖程度高,城市等级越高,依赖程度越强;②总体趋势上,植被状况越好,城市分布数目越多;城市对植被的依赖程度高,城市等级越高,依赖程度越强;③总体趋势上,地形起伏度越大,城市分布数目越少;地形起伏度对城市分布有较大影响,城市等级越高,影响程度越大;④高程对城市分布有较大影响,城市等级越高,影响程度越大。综合评价全国不同区域的城市发展适宜度,分析了适合城市发展的区域。     

DEM随机噪声误差去除方法研究——以黄土沟沿线地形剖面为例

在黄土高原数字地形分析中,基于DEM提取的地形参数和地貌对象是研究黄土地形地貌特征的基础。但在使用这些对象和参数进行小流域尺度的数字地形分析时,DEM数据中隐含的噪声在一定程度上会影响分析结果的可靠性。该文以分别位于陕北黄土丘陵沟壑区(绥德)和黄土塬区(淳化)的两个小流域为试验区,以国家基础地理数据库5m分辨率DEM为实验数据,以黄土地貌中最具典型特征的沟沿线为研究对象,对其地形剖面所隐含噪声的特征、提取及去除方法进行了研究。实验中采用EMD-MFDFA和EEMD-MFDFA两种组合方法对上述两个小流域黄土沟沿线地形剖面数据进行了分析。实验结果显示,沟沿线地形剖面数据噪声与地形复杂程度有很大关系;同EMD-MFDFA方法相比,EEMD-MFDFA对去除噪声成分具有更好的效果;EEMD-MFDFA方法在上述两个样区的沟沿线原始剖面与降噪后重构地形剖面的RMSE分别为2.053m和3.188m。     

基于GRID-TIN混合格网DEM的旱作梯田数值模拟模型研究

旱梯田地形具有独特的平面和剖面形态特征,现有DEM难以对其地貌形态特征进行准确描述,无法满足构建旱梯田地形数值模拟模型的需求。为此,以黄土高原典型旱梯田地形为切入点,基于Grid-TIN混合格网DEM和面向对象技术构建出水平梯田等典型旱梯田数值模拟模型。根据旱梯田地形的独特地貌形态特征,提出能够对旱梯田地形的高程、坡度进行准确计算的数字地形分析方法。该研究成果是对基于DEM的旱梯田地形数值模拟模型研究的有益尝试,对于探讨利用DEM实现旱梯田地形的有效数字表达与分析具有重要理论意义。     

Surface Variability of Alluvial Fans Generated by Disparate Processes,Eastern Death Valley,CA

This study explores the surface variability of alluvial fans from digital elevations model (DEM) derivatives generated from 1-m planimetric resolution airborne laser swath mapping data. Channel and interfluve dimensions of debris flow (DF) fans and fans generated from predominantly fluvial flows and some older debris flows (mixed flow [MF]) are extracted with the aid of a planimetric curvature classification. Significant differences are identified between the fan surface topography of DF and MF fans. MF fans tend to have smaller channel and interfluve widths, have smaller elevation differences between the crest of the interfluve and channel, and are more dissected than DF fans. The morphometric differences between the two fan classes can be explained by differences in the primary processes that develop the surficial features, but also the preponderance for secondary erosional processes acting on the MF fans.     

Surficial patterns of debris flow deposition on alluvial fans in Death Valley, CA using airborne laser swath mapping data

Debris flows are a common event in mountainous environments. They often possess the greatest potential for destruction of property and loss of lives in these regions. Delimiting the spatial extent of potential damage from debris flows relies on detailed studies of the location of depositional zones. Current research indicates debris flow fans have two distinct depositional zones. However, the two zones were derived from studies containing detailed analyses of only a few fans. High resolution airborne laser swath mapping (ALSM) data is used to calculate profile curvature and surface gradient on 19 debris flow fans on the eastern side of Death Valley. The relationship between these parameters is assessed to 1) identify if debris flow fans are accurately represented by two depositional zones, and 2) to assess how these terrain parameters relate to one another at the individual fan scale. The results show at least three zones of deposition exist within the sampled fans. These zones do not hold consistent when individual fan morphometry is analyzed in conjunction with localized fan surface gradients. Fans with consistently shallower gradients exhibit numerous depositional zones with more subtle changes in profile curvature. Steeper gradient fans exhibit significantly fewer zones with more pronounced local changes in profile curvature. The surface complexity of debris flow fans is evident from these analyses and must be accounted for in any type of hazard studies related to these features.     

Automatic extraction of lineament information from satellite images using digital elevation data

Using conventional visual interpretation in lineament analysis presents two main problems. The first is subjectivity, introduced because of the bias of various interpreters. The second problem is that lineaments detected from satellite images are constrained by the direction of the illumination source. Since lineament identification mainly involves recognition of diagnostic morphological features, the use of digital elevation can contribute significant information about these features. Further, in generating images using digital elevation data, the direction of illumination can easily be controlled. Thus, the use of digital elevation data offers the possibility of revealing features not apparent in regular satellite images.We discuss a sequential line detection method for extraction of linear features from digital elevation data. In this method, raw elevation data is used for generating shaded relief images using the Lambertian reflection model, wherein the illumination direction is controlled by the user. The Directional Segment Detection Algorithm (DSDA) is used for detecting linear topographic features in user-defined trends. Locational information about these linear features is stored in the computer as coordinate pairs amenable to editing and subsequent analysis. Finally, three-dimensional terrain models are generated by combining the digital elevation data and satellite images. The experiments were carried out using digital elevation data of southwest Japan and Landsat MSS data.     

基于元胞模型的河道纵剖面调整动态模拟

纵剖面的调整是河道演化的重要内容,其对于河道整治及水沙灾害机理研究都具有重要意义。利用多年观测资料可以较为精确地分析和推断河道纵剖面的调整过程。但是,这种方法不能从过程机理上对纵剖面的调整进行模拟分析。而自然条件下河道边界条件的复杂性使得对河道纵剖面演化的物理过程模拟有很大困难。元胞自动机是一个时间、空间和状态都离散的动力模型,是研究复杂系统动态演化过程的有力工具。本文以黄河尾闾河道为例,利用一维元胞模型对河道纵剖面的调整进行动态模拟。模拟揭示了河道纵剖面在初始形态、不同水沙组合以及河道延伸等情况下的演化规律与趋势。     

Spatial indexing of large volume swath data sets

This paper introduces a new hierarchical data structure that supports efficient insertion, deletion and two-dimensional range query operations on swath data. Three different spatial indexing methods were designed, implemented and compared on a large swath data set. Two of the methods are based on the Morton code sequence, and the third uses an R-tree for the index. A relational database management system (RDBMS) was used to build one of the Morton code sequence indexing methods. Experiments with the large scale data set show that R-tree indexing is superior to Morton sequence indexing by providing two to nine times faster two dimensional range search speed, occupying slightly less disk space, and supporting the range deletion operation. Time and space requirements for spatial indexing with the RDBMS were shown experimentally to be significantly worse than for the direct C code implementation of the Morton code sequence indexing.     

基于遥感影像的雪线高程提取方法对比分析——以天山北坡为例

利用2010-2014年6~8月MOD10A1、MOD10A2及HJ-1/CCD数据,以天山北坡为研究区,对比分析了积雪持续时间比率法及最大值合成法在雪线高程提取中的精度和适用性。结果表明:当MOD10A1以旬合成,积雪持续时间比率阈值为40%时,提取的雪线高程与"真值"最为接近;基于混淆矩阵法,以目视解译得到的HJ-1/CCD积雪面积为"真值",分析得出,积雪持续时间比率法提取积雪面积的总体精度较高,为98.59%,khat系数为0.90,最大值合成法的总体精度仅为85.29%,khat系数为0.70;基于统计学的方法,计算得出,积雪持续时间比率法提取的雪线高程与"真值"的相关系数较高,为0.77,其平均误差、正、负误差、绝对平均误差以及均方根误差相对较低;最大值合成法提取的雪线高程与"真值"的相关系数较低,仅为0.54,其平均误差、正、负误差、绝对平均误差以及均方根误差相对较高;积雪持续时间比率法提取的雪线高程结果优于最大值合成法。     

The extraction of elevation information of ice sheet surface on south area of the Larsemann Hills in East Antarctica

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The Balearic Promontory geomorphology (western Mediterranean): morphostructure and active processes

In this paper, a detailed study of the submarine geomorphology surrounding the Balearic Promontory (western Mediterranean), a northeast prolongation of the Neogene Betic Range in southern Spain, is presented from a series of high-resolution tools including swath bathymetry and seismic reflection profiling. The study identifies the main features of the continental shelf, slope and basins surrounding the Balearic Islands. We show a variety of seafloor relief that owes its origin to several geologic processes, which ultimately control the transport of sediment from the shallower areas to the deep basin. The most important processes are erosion of the shelf and upper slope (terraces associated with different Quaternary sea-level stands and canyons), transport and sediment deposition in the lower slope and base-of-slope by turbidity currents, volcanism and instability processes (landslides scarps and debris lobes). The swath data show that tectonics plays an important role in shaping the submarine slopes of Eivissa and Formentera, the two southernmost islands, as well as its interplay with sedimentary processes, especially mass wasting. Finally, several areas show evidence of pockmarks, which indicate that fluid migration take place in the sediments, probably conditioning several other processes such as mass wasting.     

黔西南高原区峰丛洼地的形态特征与发育规律

本文通过对黔西南坡岗地区峰丛洼地形态参数的统计和趋势面分析，论证了高原区峰丛洼地的形态特征与发育，探讨了高原区暗河纵剖面形态和喀斯特地貌演化的规律。     

拱王山风化壳的发育特征及其环境和构造意义

风化壳的化学、粘粒矿物及磁化率等实验分析表明 ,云南东川拱王山地区碳酸盐岩风化壳的红土化程度较低 ,处于Ca、Mg淋失阶段的后期或SiO2 淋失、Fe、Mn富积的早期。该地区风化壳在不同程度上存在与现代环境的不相容性。它们是在古风化壳基础上发育的继承性风化壳。在不同海拔高度的山前剥蚀面上 ,风化壳红土化程度的差异 ,是不同时期风化作用的产物。除山顶残留古夷平面上的风化壳之外 ,随海拔高度的增加 ,风化壳的风化程度存在逐渐增强的趋势 ,这一现象反映了该区新构造运动的间歇性抬升特征。