The Measurement of River Channel Morphology Using Digital Photogrammetry

This paper seeks to review the progress that is being achieved by fluvial geomorphologists in making use of digital photogrammetry for river channel research. Fluvial geomorphology is first placed in a basic historical context from which the failure to make full use of the potential of photogrammetry is noted. A review is then given of the ways in which fluvial geomorphologists are now making use of photogrammetry, recognizing that the development of digital approaches has both made photogrammetry a more cost-effective tool and also introduced a range of new research questions. The main objective of this paper is to demonstrate the importance of these questions and to illustrate some of the ways in which they are being addressed. Special attention is given to the issue of data quality, which is frequently (and perhaps conveniently) ignored.     

Study of alluvial and Talus Fans in the Garhwal Himalaya by remote sensing technique

Investigations were carried out in the Garhwal, with ranges of Lesser and Outer Himalaya. Alluvial and Talus Fans in this area are quite widespread and are generally coalescing in nature, covering linear zones almost parallel to the lesser and outer Himalyan Ranges. These fans and their deposits have been mapped and identified on the basis of the study of Landsat imagery and aerial photographs. They appear to be spreading outwordly from the escarpments often with divergent pattern of drainage. In all seven such zones of coalescing alluvial and talus fans have been identified. Zone 1 appear to be alluvial plain in front of the outer Himalayan Siwalik ranges. Zones 2, 3 and 4 may be infillings between the ranges. Whereas, zones 5, 6 and 7 may be pediplains within the Lesser Himalayan ranges. Based on the degree of their dissection, the fans in this area seems to be chronologically younger successively towards the outer parts of Himalaya.     

Statistical analysis and tectonic interpretation of the remotely sensed lineament fabric data associated with the North Almora Thrust,Garhwal Himalaya,India

A geostatistical analysis of the remotely-sensed lineament fabric data associated with the North Almora Thrust of Garhwal Himalaya has been carried out The analysis of data provided 18 major orientations of the lineament density girdles. Further statistical treatment of these derived lineaments using the method of analysts of directional data indicates that the lineaments can be classified into genetic groups. The result indicates that the North Almora Thrust and Kaliasaur Fault are not genetically related and occurred in separate phases of tectonic activities. The results also show that the Alaknanda river is flowing through a tectonically-controlled valley. The study suggests the suitability of statistical methods in lineament-fabric-data analysis for tectonic interpretations.     

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.     

石羊河流域中游景观生态格局变化及驱动分析

以石羊河流域中游为研究区,首先利用多时相、多源遥感图像提取土地利用/土地覆盖信息,根据转移矩阵,定量研究了景观类型的变化趋势、变化面积、变化率及具体的转换类型;提取能够反映景观格局特征的相关指数,分析景观生态格局及景观异质性;最后,对其景观格局变化的驱动因素进行分析。通过本次研究可以增强对石羊河流域中游生态环境的科学认识,对促进该流域的综合治理具有一定的科学和实际意义。     

Landslide risk analysis between Giri and Tons Rivers in Himachal Himalaya (India)

The area around Sataun in the Sirmur district of Himachal Pradesh, India (falling between the rivers Giri and Tons; both tributaries of the Yamuna River) was studied for landslide vulnerability on behalf of the inhabitants. The study was made using extensive remote sensing data (satellite and airborne). It is well supported by field evidence, demographic and infrastructural details and aided by Geographic Information System (GIS) based techniques. Field observations testify that slope, aspect, geology, tectonic planes, drainage, and land use all influence landslides in the region. These parameters were taken into consideration using the statistical approach of landslide hazard zonation. Using the census data of 1991, vulnerability of the populace to the landslide hazard was accessed. As most of the infrastructure in the region is concentrated around population centres, population data alone was used for vulnerability studies.     

Terrestrial photogrammetric mapping of the Neh-Nar glacier in Himalaya, India

Terrestrial photogrammetry holds distinct advantages over the conventional theodolite survey or aerial photogrammetry for glacier surveys, on account of inaccessibility of upper reaches of the glaciers and non-suitability of large-scale aerial photography for very high relief areas. The Neh-Nar glacier was mapped with a contour interval of 10 m utilising terrestrial photogrammetric techniques because no large-scale base map of the glacier was available for detailed glaciological studies. This glacier was selected under the International Hydrological Programme. Apart from topographic details various features of glaciological significance like transient snowline, accumulation and ablation zones, bergschrund, icefalls etc., were also mapped.     

数学形态学在地图模式识别中的应用

扫描数字化是 GIS中快速获取地理数据的手段之一 ,其关键是对扫描图上的地图要素进行自动识别。文中针对地图模式识别的关键技术之一图像分割进行了研究 ,利用数学形态学方法实现了地图上部分要素的分割     

Plate Motion of India and Interseismic Strain in the Nepal Himalaya from GPS and DORIS Measurements

We analyse geodetically estimated deformation across the Nepal Himalaya in order to determine the geodetic rate of shortening between Southern Tibet and India, previously proposed to range from 12 to 21 mm yr^?1. The dataset includes spirit-levelling data along a road going from the Indian to the Tibetan border across Central Nepal, data from the DORIS station on Everest, which has been analysed since 1993, GPS campaign measurements from surveys carried on between 1995 and 2001, as well as data from continuous GPS stations along a transect at the logitude of Kathmandu operated continuously since 1997. The GPS data were processed in International Terrestrial Reference Frame 2000 (ITRF2000), together with the data from 20 International GNSS Service (IGS) stations and then combined using quasi- observation combination analysis (QOCA). Finally, spatially complementary velocities at stations in Southern Tibet, initially determined in ITRF97, were expressed in ITRF2000. After analysing previous studies by different authors, we determined the pole of rotation of the Indian tectonic plate to be located in ITRF2000 at 51.409±1.560° N and ?10.915±5.556°E, with an angular velocity of 0.483±0.015°. Myr^?1. Internal deformation of India is found to be small, corresponding to less than about 2 mm yr^?1 of baseline change between Southern India and the Himalayan piedmont. Based on an elastic dislocation model of interseismic strain and taking into account the uncertainty on India plate motion, the mean convergence rate across Central and Eastern Nepal is estimated to 19±2.5 mm yr^?1, (at the 67% confidence level). The main himalayan thrust (MHT) fault was found to be locked from the surface to a depth of about 20 km over a width of about 115 km. In these regions, the model parameters are well constrained, thanks to the long and continuous time-series from the permanent GPS as well as DORIS data. Further west, a convergence rate of 13.4±5 mm yr^?1, as well as a fault zone, locked over 150 km, are proposed. The slight discrepancy between the geologically estimated deformation rate of 21±1.5 mm yr^?1 and the 19±2.5 mm yr^?1 geodetic rate in Central and Eastern Nepal, as well as the lower geodetic rate in Western Nepal compared to Eastern Nepal, places bounds on possible temporal variations of the pattern and rate of strain in the period between large earthquakes in this region.     

伊犁河谷天然植被覆盖度的变化特征分析

利用2000-2015年植被生长季(4~10月)MODIS/NDVI产品反演生成同时相的植被覆盖度数据,运用趋势性分析方法和皮尔逊相关系数法,进行了不同类型自然植被覆盖度时空变化特征及其与降水量、平均气温的驱动因素分析。结果表明从多年平均状态看,针叶林的植被覆盖度高于其他天然植被,灌丛类的最低,荒漠和灌丛类的植被覆盖度总体呈递增趋势;从年际尺度上看,草原和灌丛类植被对气温和降水量的响应规律大致呈反方向;不同类植被在春季(4月)对气温和降水量反映的差异性最大,与春季为新疆融雪高峰期有一定关系。     

Mapping of seagrass meadows from the lakshadweep islands (India), using aerial photographs

Seagrass meadows from the Lakshadweep islands were mapped with the help of black and white aerial photographs. A maximum of 40 ha seagrass cover was estimated in the lagoon of Minicoy, followed by Kavaratti (34 ha). The total seagrass cover from six major islands of Lakshadweep was estimated to be 112 ha with standing crop of ca 800 metric tonnes. The dominant seagrass species observed wasThalassia hemprichii whileCymodocea rotundata, Halophila ovata, Syringodium isoetifolium andHalodule uninervis were common to these islands.     

Geoinformatics based approach for estimating the sediment yield of the mountainous watersheds in Kashmir Himalaya,India

Sedimentation of water bodies is governed by the erosional processes occurring at the watershed level. In this research, a method is proposed for assessing the sediment yield of the mountainous watersheds surrounding the Wular lake in Kashmir Himalaya, using geoinformatics and geostatistics. This method is empirical and semi-quantitative in approach and takes into account the weightage-based influence of the parameters governing the watershed sediment yield. The results of this study reveal that out of the six surrounding watersheds of the Wular Lake, Madhumati watershed with the highest sediment yield index, SYI (39.78) drains maximum sediments into the Lake followed by Arin (39.27), Ferozpur (34.30), Wular II (32.53), Wular I (24.65) and Gundar (23.43) in the event of a same intensity storm. The proposed method is reasonably a better approach in the data-scarce Himalayan region and shall be a useful tool for watershed management in other regions with similar geographic setting.     

Assessing changes in the above ground biomass and carbon stocks of Lidder valley,Kashmir Himalaya,India

The changes in the land use and land cover (LULC), above ground biomass (AGB) and the associated above ground carbon (AGC) stocks were assessed in Lidder Valley, Kashmir Himalaya using satellite data (1980–2013), allometric equations and phytosociological data. Change detection analysis of LULC, comprising of eight vegetation and five non-vegetation types, indicated that 6% (74.5 km²) of the dense evergreen forest has degraded. Degraded forest and settlement increased by 20 and 52.8 km², respectively. Normalized difference vegetation index was assessed and correlated with the field-based biomass estimates to arrive at best-fit models for remotely sensed AGB estimates for 2005 and 2013. Total loss of 1.018 Megatons of AGB and 0.5 Megatons of AGC was estimated from the area during 33-year period which would have an adverse effect on the carbon sequestration potential of the area which is already facing the brunt of climate change.     

Geo-spatial approach for phytodiversity characterization in Panna National Park (part), M.P. (India)

Panna National Park is situated in the north-central part of Madhya Pradesh, India. Landscape parameters like fragmentation, porosity, patchiness and jaxtaposition have been analysed for disturbance gradient characterization. Disturbance on biodiversity due to human activities has been studied both qualitatively and quantitatively. The species richness is highest in northern mixed dry deciduous forest followed by dry deciduous open scrub and southern tropical dry deciduous teak forest. Species richness of the open thorny dry deciduous forest with grasses is found to be the lowest. Disturbance analysis indicates that 22.02% of the southern slightly moist teak forests are highly disturbed whereas Anogeissus forest and Riverine forest have 17.04% and 12.41% of the area under high disturbance, respectively. A total of 88 field sample plots were laid to enumerate trees, shrubs, herbs, climbers, etc. Biological richness parameters such as Shannon-Wiener biodiversity index, biodiversity value, ecosystem uniqueness were derived from field data. High biological richness is found in northern mixed dry deciduous forest and mixed dry deciduous forest with bamboo. More than 99% of such areas are falling under medium to high biological richness. Nearly 55% of the gentle and flat to gentle, slope categories were found to have low biological richness. Phytosociological analysis of sampled field data indicated that the number of trees per unit area is the lowest in the Savannah. In inaccessible areas, the species richness and number of trees per unit area is very high. Main forces causing disturbance are search for diamonds, dams on river Ken, settlements in and around the park, grazing and resource utilization by villagers for fodder, animal grazing, fuel-wood, timber, etc.     

北江芦苞浅段河道演变及其影响因素分析

本研究以1988～2001年共4个时相的遥感影像作为数据源,对北江芦苞浅段岸线和洲滩变化进行对比分析,结果表明90年代以后此段河道河势发生了较大的变化,主要体现在河道主流线的迁移、小型洲滩的消亡,变化时间与人为采砂和航道整治的时间相吻合,河势向着稳定的趋势发展,文章最后对河道演变的影响因素进了初步探讨。     

基于RS的宝兴河流域LUCC变化分析

本文基于1994年LandsatTM、1999年的ETM＋及2007年的ETM＋遥感影像,在ENVI和ERDAS的支持下提取宝兴河流域的土地利用/覆被变化情况。引入土地利用类型的年变化率、综合土地变化动态度等指标,分析其原因及土地利用的时空变化特征和规律。研究结果表明：1994年到2007年,耕地主要集中在宝兴河流域的东南部平坝地区,呈逐年变少趋势,减少44.7%;林地主要分布在西北高山及中部地区,呈逐年增加的趋势,增加6.5%;草地主要集中在西北高山区,其变化为先减少后增加,总体减少19.3%。     

Study of drainage pattern of Jharia Coalfield (Bihar), India, through Remote Sensing technology

Study of drainage pattern of Jharia Coalfield as observed on IRS-IA LISS II image shows that the region is drained by 11 streams with general flow direction to north east to south east and ultimately joining to trunk river Damodar. The perennial river Damodar flows from west to east and approximately marks the southern limit of the famous Jharia Coalfied. The average stream length in the region varies from 15 km to 110 km with average hasin area from 10 km² to 150 km². The general pattern is essentially a coarse dendritc with very gentle (0 to 1%) to sluggish stream flow condition over a gentle sloping (1 to 3%) topographic surface characteristic of old age streams in matured erosion terrain (Paleo-pediplain).     

红水河中游地区地质构造稳定性的遥感图像分析

红水河中游地区是以北西向和北东向断裂相交叉为基本构造格局。在新构造运动时期,这两组老构造分段复活,将该区分割成一个相对独立的活动块体。 遥感信息与岩相古地理及汞矿化带相结合的分析结果表明:发震的垭都—紫云深大断裂,在新构造运动时期并未进入断块。遥感信息与历史震中的时空分布和断块结合分析表明:中强震震中绝大多数分布在断块以外,并以右江断裂带以南的频率为最大,由于这里已远在百公里之外,今后若再发生中强震,经过长途衰减,波及坝址的影响有限。 断块内距坝址15—20公里的巴鱼地区,近期发生过4.6级地震。这是一个处在乐业环状构造长轴转折端前沿,也是逻西活动断裂等多组断裂交叉处,小型环状构造也很发育,构造应力容易在此集中,历史震中与小型环状构造同断裂的交叉点关系密切。影像显示该区是相对孤立的局部地段,小震频繁,应力分阶段释放,不具备孕育强震的条件。 龙滩和岩滩电站坝址周围8公里内无大型或活动断裂通过,亦无两组以上断裂交叉点出现,构造稳定性良好,但应注意水库诱发地震的研究。     

右江谷地景观格局空间分异特性遥感研究

利用1986年和2006年获取的TM图像,在GIS技术支持下,运用景观生态学原理,选取反应景观空间结构和景观异质性的景观指数,以右江谷地典型区广西平果县为研究区,分析该区近20 a间的景观格局及其动态变化特征.结果表明,1986～2006年间,平果县土地利用变化总趋势是林地、未利用地和居民地面积增加,草地、耕地和水域面...     

扬子江城市群城镇空间格局演变解析

以扬子江城市群为研究对象,从城市群建成区扩张和城镇空间联系两个角度进行指标分析,综合测度了2005年、2010年、2015年的城市群城镇发展水平,并利用探索空间数据分析法对城市群城镇空间格局进行了研究。结果表明:①监测周期内,城市群各市的扩张均处于全省前列,"十一五"和"十二五"期间扬子江城市群建成区扩张迅速、效应明显,3期城市群建成区空间重心都集中在扬子江以南的常州市境内,表明扬子江以南的城镇发展规模优于江北;②从城镇空间联系来看,宁镇杨、苏锡常、苏通等城市组群的联系相对明显,构成了整个扬子江城市群的基本联络骨架,城市群内部各城市与周边城市之间、小城市与大城市之间的联系紧密,构成了联系网络。