辅以地貌类型的喀斯特地区土地利用信息提取

地貌限制土地利用形式,土地利用类型又影响着地貌的形成与演化,基于以上关系提出一种辅以地貌类型的面向对象土地利用信息提取方法。以喀斯特地貌类型分布多样的安顺市为例,选取2010年的TM影像作为基本的数据源。首先,根据不同喀斯特地貌组合的尺度响应特征对试验区影像进行多尺度分割;进而利用数字高程模型(digital elevation model,DEM)数据以及衍生的坡度、地形起伏度和地表切割深度等特征,建立隶属度函数提取喀斯特地貌信息;最后,以地貌类型为基本分类单元,根据不同地貌类型的土地利用特点,采用面向对象的分类方法对土地利用信息进行提取。结果表明:面向对象的分类方法可以对喀斯特地貌类型进行自动提取,试验区地貌类型主要以峰丛谷地、峰丛洼地为主,峰林溶源与峰林盆地分布较少。土地利用类型以灌木与旱地为主,分别占总面积的25.58%和20.74%,土地利用信息提取总体精度达到87.35%。     

基于DEM的格尔木河流域水系分维分析

分形理论为流域的复杂地貌形态及其发育过程等方面提供了定量依据,为进一步深化流域水系的分形研究,以ASTER-GDEM数据为基础资料,运用GIS水文分析工具提取了格尔木河流域在不同汇流累积量阈值下的水系河网;并用盒维数法计算了相应的水系分维数,以此来描述流域的地貌形态特征;并进一步预测流域地貌的发育演化趋势.研究结果表明:在一定无标区间范围内,汇流累积量阈值和分维数拟合较好;计算得到格尔木河流域的水系分维值处于1.6～1.8之间,据此可以判断出该流域处于地貌侵蚀发育壮年期,并向壮年晚期发展,流域地势起伏大,地面切割得支离破碎、崎岖不平,河流以侧蚀为主,下切作用相对较弱,与流域高程面积积分值计算所得结论一致.     

数字高程模型格网间距对提取地形因子的影响研究

数字高程模型(DEM)作为地面高程信息的数字表示形式,在地学研究领域得到了广泛应用.本文通过对DEM基本原理及其现有表示形式进行分析,提出了数字等高线也是DEM表示形式的观点.随后通过选取4种不同地貌类型的规则格网DEM作为实验区,分析研究了DEM格网间距对坡度、坡面曲率、地表切割深度、地表粗糙度和沟谷密度等地形因子提取的影响,为人们根据地貌类型和应用需求合理选择DEM分辨率提供了参考.     

基于RS和GIS的龙门山南段活动构造信息提取

以龙门山南段为研究区,基于ETM和DEM数据,应用主成分分析显示断裂相关地层、水系信息差异,定向滤波分析断裂位置及活动性。通过山体阴影分析、坡度分析,发现研究区域地势及地表坡度变化强烈的地区是断裂构造较发育或活动的区域,为活动构造的解译提供依据。初步建立研究区活动构造解译标志,对区内的线性构造进行解译,分析研究区主要活动构造分布特征和地质地貌特征。     

基于DEM的流域特征提取研究——以贵州省普定县后寨河流域为例

本文以喀斯特后寨河流域为例,探讨了在Arcgis 9.0环境下从数字高程模型(DEM)中提取流域特征的详细过程,包括:DEM的生成和预处理、水流方向的确定、汇流累积量分析、河网的提取和子流域的划分以及落水洞的计算。经分析得到了研究区域河网特征以及研究区其他常用的流域特征信息,与实际河流水系特征基本吻合,从而证明该方法在分析流域的河网水系结构特征时具有一定的应用价值。     

基于Google Earth影像的漓江水系形态特征提取与分析

为获取漓江流域水系的空间分布和水系形态特征,以Google Earth影像为数据源,采用人机交互目视解译法提取了流域内的水系形态特征信息,编制了漓江流域水系分布图。通过对水系的等级、密度、分支比、各级水道长度以及交汇角等特征信息进行统计,定量化地展示了漓江流域水系的形态特征;在此基础上进行水系形态特征的控制因素分析,认为地层与断裂构造是控制漓江流域形态的重要因素,人类活动对漓江流域水系形态的影响正在日渐增强。该研究成果为漓江流域的综合治理提供了科学依据,深化了漓江流域的地貌研究。     

SRTM(1″)DEM在流域水文分析中的适用性研究

高精度的数字高程模型(digital elevation model,DEM)数据是流域水文分析应用的基础。美国地质调查局新发布了全球高分辨率数字高程数据产品,其空间分辨率为1″(约为30 m)。为评价该数据在流域水文分析中的适用性,以鹤壁汤河流域为实验区,以机载LiDAR DEM数据为参考,统计了SRTM(1″)数据的高程误差,分析了坡度、坡向、地表覆盖等对误差的影响;在基于地形的水文分析中,统计分析了SRTM(1″)数据误差对地形湿度指数、坡度坡长因子以及汇流动力指数等地形指数计算的影响;最后选取流域汇水区面积、最长水流路径长度、形状系数、弯曲度系数等流域特征参数对两种DEM数据提取结果进行了对比。研究表明SRTM(1″)DEM数据具有较高的精度,原始数据均方根误差为5.98 m,在消除平面位移误差后减小为4.32 m。基于地形的水文分析表明SRTM DEM与LiDAR DEM计算结果具有一定的差异,地形湿度指数平均值略高,坡度坡长因子和汇流动力指数平均值偏低,离散度偏小,这与SRTM DEM在微地貌以及高坡度地形区存在失真相关。两种DEM数据提取流域特征参数差异较小。上述研究表明SRTM DEM(1″)数据在流域水文分析中具有较大的应用潜力。     

庐山地区面积高程积分提取及其空间特征研究

以庐山为研究区,基于4种不同来源的DEM数据源。首先选取样区,利用空间插值等方法对面积高程积分提取结果进行评价,选取出适宜的数据源。然后,根据最优数据源对庐山地区面积高程积分的空间特征进行探究。结果表明,江西省测绘地理信息局生产的DEM和ASTER GDEM V1适宜作为数据源;庐山地区地貌发育以壮年期为主;断层区域则产生明显的空间分异,体现了断层构造对庐山地区流域地貌发育的深刻影响。本研究对了解庐山地区的流域地貌发育具有重要意义。     

芦山地震灾区典型泥石流沟发育特征分析

本文以芦山地震灾区冷木沟和校场沟两条已有治理工程的泥石流沟作为研究对象,利用1∶1万比例尺DEM数据分别采用坡度坡向分析法和面积-高程分析法做泥石流沟地貌发育特征分析和地貌发育程度分析。结果表明冷木沟与校场沟地质环境较差,并且仍处于壮年期,易发生泥石流等地质灾害,发生频率不是很高,但规模可能很大。再利用不同时期的遥感影像对流域面积进行解译,计算流域范围内的植被覆盖率,分析灾后重建植被恢复情况。     

基于ICESat-2 ATLAS数据的DEM高程精度评价

为探究ASTER GDEMV3、SRTM1 DEM和AW3D30 DEM 3种开源DEM数据的高程精度,本文以高精度ICESat-2 ATLAS测高数据为参考数据,利用GIS统计分析、误差相关分析及数理统计对DEM的高程精度进行对比评价。结果表明：①AW3D30的质量最稳定;SRTM1 DEM在平原精度最高;在高原山地精度由高到低依次为AW3D30 DEM、ASTER GDEMV3、SRTM1 DEM。②DEM数据高程精度受地表覆盖影响较大,且与地形因素密切相关,在相同地表覆盖的两个研究区中DEM数据高程精度表现情况不一致,SRTM在平原地表覆盖下精度表现最好,平均误差为3.15 m,AW3D30 DEM在山地地表覆盖下精度表现最好,平均误差为7.61 m。③坡度对DEM数据的高程精度影响较大,在两个研究区3种DEM数据的高程误差均随坡度的增加而增加;坡向对DEM数据的高程精度影响较小,未发现明显的规律。     

基于GIS的岩溶古地貌定量刻画方法分析研究

恢复岩溶古地貌对于分析岩溶储层发育特征具有重要作用。目前关于岩溶古地貌的恢复多为定性方法,定量刻画古地貌的水平有待提高,而GIS在定量分析处理地貌方面独具优势。以高石梯—磨溪区块灯四段岩溶储层为例,在经典古地貌恢复方法的基础上,从GIS的地貌因子出发,提取了包括高程、坡度、地表切割深度、地表粗糙度、地形起伏度在内的地形因子以及包括水流长度、河流等级、流域分析在内的水文因子;再选取核心地形因子,并对地貌因子进行敏感性评价,结果显示高程、坡度和地形起伏度对地形的表征贡献较大。以地貌成因—形态分类原则为地貌分类方案,对敏感地形因子进行重分类操作后作叠加分析处理,地貌分区成图显示研究区由岩溶高地、岩溶缓坡、岩溶缓坡过渡带和岩溶洼地4类地貌单元组成。对岩溶古地貌进行分析评价发现,岩溶缓坡为油气良好集聚地,地貌划分结果与储层分布具有相关性。     

Morphometric analysis of Upper Tons basin from Northern Foreland of Peninsular India using CARTOSAT satellite and GIS

The morphometric analysis of river basin helps to explore the interrelationship between hydraulic parameters and geomorphologic characteristics. The study has been conducted in the Upper Tons basin of Northern Foreland of Peninsular India. The river basin has been characterized using the topographical maps, CARTOSAT satellite image integrated using the GIS techniques. The drainage density analysis indicates lower values in the north-eastern regions and thus these regions can be categorized as better ground water potential zone. There are in total 10 sub-watersheds which have been delineated; SW-4 has maximum drainage density (4.75), stream frequency (5.61) and drainage texture (26.64) followed by SW-6–10. The prioritized sub-watershed numbers SW-4 and SW-6–10 need conservation practices because of their high erodibility and run-off. SW-1–3 and SW-5 regions have better permeable bed rocks and hence good for water harvesting. The areal parameter indicates elongated shape of basin and moderate to steeper ground slope. The results are supported by extensive field survey. This study can be applied for soil and water management, as well as disaster prevention from similar type of drainage basins.     

Morphology and evolution of an alluvial fan-a case study of Kalanutala,Prakasam district,A.P.

Alluvial fans are the dominant landforms of the semi-aird and arid environments of the world. Studies on alluvial fans elsewhere suggest that there is a close relationship between the morphology of the fan and the drainage basin area; lithology, mean slope, vegetation, climatic and tectonic environments of the source area. An alluvial fan at Kalanutala village, in Prakasam district of Anthra Pradesh, has been studied in detail in order to analyse it's morphology and arrive at its geomorphic evolution. From a study of fan morphology and it's composition, it has been arrived, at the conclusion that there is a relationship between the fan and it's drainage basin (Kompayasela). Further, this study reveals that the apparent segmentation of the fan is not because of tectonic movement but due to the underlying topography of pediment. The study of fan morphology and its materials suggests that the initial deposition of fan took place in a humid climate, but gradually changed to the present arid climate.     

Evaluation of drainage networks developed in hard rock terrain

An attempt was made to study the influence of various factors such as geology, landforms, slope, soil, landuse/cover on the development of the drainage network. To compare and evaluate drainage networks developed in various geologic terrains, differing in rock type and structure, three sub-basins of the Bhadra river basin, located in Chikmagalur district, Karnataka, India were selected for the study. Quantitative morphometric analysis was carried out for both linear aspects and areal aspects for all three sub-basins. The applicability of Horton's laws was also studied. Each of the quantitative parameters was interrelated with thematic details derived from remote sensing data. The results of the study indicate that the drainage characteristics are entirely different for all three sub-basins. The study has also established the applicability of Horton's laws pertaining to quantitative morphometry of the sub-basins.     

数字高程模型在坡耕地调查中的应用

以1:1万比例尺地形图(H-48-72-24)为例,采用地理信息系统软件Arc/Info数字化地形图生成数字高程模型,并通过DEM计算派生出坡度图,再结合土地利用现状图和相关资料,应用地理信息系统空间分析功能,自动提取坡耕地数据。整个过程主要由计算机进行处理,人工干预少,效率高。     

Identification of basin characteristics influencing spatial variation of river flows

The selection of basin characteristics that explain spatial variation of river flows is important for hydrological regionalization as this enables estimation of flow statistics of ungauged basins. A direct gradient analysis method, redundancy analysis, is used to identify basin characteristics, which explain the variation of river flows among 52 selected basins in Zimbabwe. Flow statistics considered are mean annual runoff, coefficient of variation of annual runoff, average number of days per year without flow and selected percentile flows. Basin characteristics investigated are those likely to reflect climatological, topographical and hydrogeological influences including that of land cover on river flows. The first ordination axis of flow statistics is strongly correlated with mean annual precipitation, mean annual potential evaporation and median slope. This ordination axis explains 64% of the variation of selected flow statistics among the selected drainage basins. The proportions of a basin under cultivation, and that with grasslands are correlated with the second ordination axis, which explains 6% of the variation of selected flow statistics. Mean annual precipitation is the most important basin characteristic, and this alone explains 50% of the variation of flow statistics. Median slope is the second most important basin characteristic. Proportions of a basin underlain by different lithological types had no effect on flow characteristics of selected basins. The paper has demonstrated the ability of redundancy analysis to identify basin characteristics that explain the variation of river flows among basins, including estimating the relative importance of these basin characteristics.     

Study of drainage pattern of Raniganj Coalfield (Burdwan district) as observed on Landsat-TM/IRS LISS II imagery

Drainage pattern of Raniganj Coalfield basin has been mapped as observed on false colour composites of Landsat TM and IRS-LISS II imagery and their characteristics have been interpreted in terms of basin morphology, surface materials and underlying rock types. The drainage system of the region is composed of 3 perennial rivers with 15 ephemeral nalas and jhors which as a whole flows on recent peneplain basin. Although, on an average, nalas and jhors of the area have smaller stream length and with smaller basinal area but they hold sufficient amount of water during monsoon and therefore by effective planning and management, surface water resources could be enhanced in the region.     

基于地形梯度的山地流域土地利用格局及时空演变研究——以云南小江流域为例

地形差异是山区土地利用结构和空间格局分异的重要影响因素,云南小江流域作为典型山地流域的代表,针对其土地利用结构不合理导致生态环境恶化的问题,文中提出利用小江流域1990、2000、2010年三期土地利用数据,采用GIS空间分析技术,在简要分析土地利用宏观总体格局及变化的基础上,分析流域4大垂直带谱的土地利用格局,并分析驱动因素。重点从高程和坡度两个因子分析流域土地利用格局及演变的地形梯度特征,得出土地利用变化所在的各地形梯度位置范围,可为小江流域土地利用结构优化、土地资源合理利用和生态环境治理及改善提供重要参考。     

REMOTE SENSING METHODS IN RESEARCH ON RIVER DRAINAGE BASINS

The concept that river drainage basins can be considered appropriate spatial units in assessment of human environmental impacts is examined. Applications of remote sensing imagery in the study of changes occurring within a particular basin—the Sit' River in European Russia—are investigated and multispectral aerial photography is used to determine the structure of biotic communities. Regionalization and areal cataloguing of these communities are the basis for specific conclusions regarding the principal sources of entry of nutrients and pollutants into the basin. Three image feature classification methods used to identify such communities (K-means (unsupervised) based on principal components analysis, supervised using principal components analysis, and data compression and subsequent identification of principal components) are compared in terms of effectiveness (numbers of mixed and/or unclassified pixels). Translated by Edward Torrey, Alexandria, VA 22308 from: Izvestiya Akademii Nauk, seriya geograficheskaya, 1994, No. 1, pp. 126-140.     

坡度分级对地面坡谱的影响研究

地面坡度是最重要的地形定量指标之一,建立科学合理的地面坡度分级体系对坡度进行科学研究具有重要的意义。总结了近些年在坡度分级研究方面的已有成果,利用高精度1∶10000 DEM数据为信息源,提取了不同分级的坡谱,研究了不同分级方法及等差分级的不同级差对地面坡谱的影响。结果表明:不同的坡度分级法可以获得不同的地面坡谱表达;自定义分级法得到的坡谱对具体的应用有实际指导意义,模式分级法可以更好地表达地表形态;3°等差分级的坡谱在实际研究中更具适用性。