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).     

Estimation of the Aerial Cover of Seagrasses of Lakshadweep Islands (India) Using Indian Remote Sensing Satellite (IRS P6 LISS IV)

Seagrasses ecosystems are fragile yet highly productive ecosystems of the world showing declining trend throughout the world due to natural and anthropogenic pressures. Effective conservation and management plan is thus required to protect these resources, to aid with conservation need mapping and monitoring of seagrasses using high resolution remote sensing data is very much required. Hence, the present study was made to record the seagrass aerial cover in the Lakshadweep islands using IRS P6 LISS IV satellite data. The suitability of LISS IV sensor for seagrass mapping was tested for the first time with an overall accuracy of 73.16%. The study found an area of 2590.2?ha of seagrasses in Lakshadweep islands with 1310.8?ha and 1279.4?ha dense and sparse seagrass cover respectively. The study recommends the use of LISS IV data for mapping the shallow water seagrasses, as mapping efficiency increases nearly 4 times more than the LISS III data, as the former (LISS IV) picks up the small patches of seagrasses and delineates the coral and reef vegetation patches from seagrass class.     

Study of drainage pattern through aerial data in Naugarh area of Varanasi district, U.P.

Drainage pattern of Naugarh Block of district Varanasi has been mapped. The basin characterestics have been analysed is terms of basin morphology and related parameters. The drainage system of the region is composed of 3 perennial rivers with 7 sub-basins. A total of 1223 streams. of 1st to 6th order exist, out of which 761 are of 1st order and 350 of 2nd order which hold sufficient amount of water duing the peak monsoon period Surface water resources could be enhanced in the region by constructing check dams and creating artificial recharge through effective and management.     

The use of WorldView-2 satellite imagery to model urban drainage system with low impact development (LID) Techniques

Within a wide range of best management practices for stormwater management in urban areas, there has been an increasing interest in source control measures. Source controls such as low-impact development (LID) techniques are potentially attractive as retrofit options for older developed areas that lack available land to implement conventional measures such as stormwater management ponds. Hence, distributed urban drainage models requiring detailed representation of developed drainage areas should be developed to accurately estimate the benefits that LIDs may provide. This study (1) presents a two-stage classification process on a high-resolution WorldView-2 image, and (2) demonstrates how to use the extracted land cover information in the subsequent hydrologic modelling and assessment of different LIDs’ performance. The proposed two-stage classification method achieved an overall accuracy of 80.6%, whereas a traditional pixel-based achieved 68.4% in classifying the same urban area into six land cover classes. From the classification results, the hydrologic properties of micro-subcatchments were imported in the United States Environmental Protection Agency Storm Water Management Model to assess the performance of LIDs. A reduction of run-off volume 18.2% and 37.1% was found with the implementation of porous pavement and bioretention, respectively, in a typical low-rise residential area located in the city of San Clemente, California, US. The study demonstrates the use of high-resolution remote sensing image to aid in evaluating LID retrofit options, and thus benefits in situations where detailed drainage area information is not available.     

Interpretation of Synthetic Aperture Radar (SAR) imagery for geological appraisal: A comparative study in Anantapur district of Andhra Pradesh

The paper describes the details of a comparative study of geological interpretations carried out from Synthetic Aperture Radar (SAR) imagery, Landsat MSS (B & W) imagery and Aerial Photographs, covering 2100 sq km of area in Anantapur district of Andhra Pradesh. The area comprises Peninsular—Gneissic Complex and rocks of Dharwar and Cuddapah Super Groups beside the Quaternary alluvial deposits along the Penneru river and its tributaries. Geomorphologically the areas is represented by denudational, fluvial and structural landforms. The study indicates that the details of the geological and geomorphological maps prepared from SAR imagery and aerial photographs are comparable despite the smaller scale of SAR imagery while the same are not exhibited in Landsat imagery mainly due to its low resolution. Although broad lithological units are possible to be discriminated on SAR as well as aerial photographs, some of the finer rock types viz. gabbroic dykes could be discriminated from the delerite dykes in the SAR imagery due to their different surface roughness. Stereoscopic coverage and enhanced micro-relief of SAR imagery gives better geomorphological details in comparison to aerial photographs. A detailed study of lineaments has also been carried out which shows that in SAR imagery there is over-representation of short lineaments due to enhanced micro-relief and radarshadow effects across the look direction and under-representation of lineaments along the look direction. Landsat imagery is perhaps the best for demarcating lineaments of regional magnitude while aerial photographs are good for depicting shorter lineaments. However, certain lineaments seen in SAR imagery are often not continuously seen on aerial photographs.     

Evaluation of Cartographic accuracy of IRS-1A LISS II data for upgrading linear details on the existing maps (A case study of Chandigarh area)

Considering the fest pace of development, up-to-date maps have become imperative in developmental planning. Conventional map updating techniques are expensive and time consuming. The present paper makes an attempt to tackle the problem using GIS techniques. Maps generated from IRS-1A LISS II data and Survey of India (SOI) toposheets were used as input maps in GIS. These maps were overlaid to obtain the positional errors at road junction points. The area statistics of each sector were calculated taking the SOI map as reference data. The results show that the areas calculated from LISS II data and SOI map are well comparable and the deviations are within 10%, whereas the positional accuracy (MSE) of points is within 30 m. The study demonstrates that the IRS-1A LISS II data can be used for updating of maps on scale 1:100,000 and smaller in areas where linear features are identifiable in the IRS LISS II image.     

Manual interpretation of (land sat-1) imagery for assessment of area under shifting cultivation in the district of Keonjhar,Orissa-India

In order to prepare schemes for Land reclamation, plantation and permanent settlement of the tribals of shifting cutivation areas in Orrisa a proper survey is a prerequisite. Earlier attempts vaguely idenified these areas. Wide disparity in data are found in the reports from different sources. Interpretation of LANDSAT-1 imagery can be used to study shifting cultivation areas in a scientific way. Lack of forests on sloping land is the chief characteristic of shifting cullivation areas. Landsat observation along with classified slope from topographic sheets provide most reliable and accurate data by minimising human error.     

Geomorphology and Petroleum Prospects of Cauvery Basin,Tamilnadu, Based on Interpretation of Indian Remote Sensing Satellite (IRS) Data

Geomorphological studies of the Cauvery basin, Tamilnadu were carried out using IRS images with special emphasis on identification of zones of hydrocarbon occurrences. The basin exhibits landforms of fluvial and fluvio-marine plains. Two major trends of lineaments and 15 circular anomalies have been identified. The NW-SE trend appears to be younger and might have played an important role in migration and entrapment of hydrocarbons. Six circular anomalies are associated with known oil/gas wells. The study has identified probable zones of hydrocarbon occurrences.     

Study of flood affected area of ephemeral streams (choes) around mahilpur in Hoshiarpur district,Punjab, using photo-interpretation techniques

Conventional aerial Photographs coupled with the old and present topographical maps are used to map the flood affected areas of emphemeral streams around Mahilpur in Hoshiarpur district of Punjab State. These streams have their origin in the Sub-mountainous zone of Siwaliks in Punjab and being turbulent in nature are the main cause of Soil erosion in the Siwaliks. In the plains such streams spread out and deposit large amount of sand eroded from the Siwaliks over fertile lands resulting them unproductive. An endeavour has been made by the authors to delineate and study the past and present flood affected areas of these ephemeral streams in the light of flood protection measures; Soil conservation measures; and improved agricultural practices adopted by the State Government and the individual inhabitants of the area.     

改进的GNSS水准地球重力场模型评价

利用GNSS水准进行地球重力场模型精度评价是一种常用的外符合精度评价方法。针对GNSS水准与模型大地水准面高常存在较大的偏差,且常用的数学拟合方法会掩盖造成系统偏差的因素这一问题,该文分析了GNSS测量大地高的时变影响、全球大地水准面与水准测量起算面之间的区域性基准差,同时提出了顾及时变影响的GNSS水准地球重力场模型评价方法。     

虎门大桥GPS(RTK)实时位移监测方法研究

由于大跨度悬索桥和斜拉桥的结构特点,实时监测台风,地震,车载及浊度变化对桥梁变形的影响显得越来越重要,如何获取实时并将所得的数据进行安全分析,成为大桥安全性研究的另一课题,本文介绍了利用GPS（RTK）技术监测虎门大桥实时位移的方法研究和实现途径。     

基于天顶湿延迟的GPS大气折射率剖面反演研究

利用青岛地区的历史探空数据,仿真得到其天项湿延迟。基于天项湿延迟和历史折射率剖面的统计关系,建立了折射率剖面的线性统计模型,回归得到模型参数。仿真比较结果表明,该方法优于常规气象模型,并有一定的容错性。     

GM(1,1)变形建模中元素选取的对比研究

以某煤矿工作面内某点的沉降观测数据为依据,分别选取累计变形量、单次变形量以及日变形速率为建模元素获取建模序列,用c#对该点建立均值GM(1,1)模型,得到3种不同建模序列的沉降预测值.对比分析发现,单次变形量以及变形速率序列对建模数据预测优于累计变形量序列.而且若等周期观测,变形速率与单次变形量预测效果相同;非等周期观...     

基于新型水体指数(NWI)进行水体信息提取的实验研究

基于遥感数据构建的水体指数模型可用于水体信息的提取。本文在对水体及其背景地物进行光谱特征分析的基础上,结合水体在近红外和中红外波段(相当于Landsat TM/ETM+影像的Band 4,Band 5和Band 7)同时具有强吸收这一典型特征,提出了一种新型的水体指数NW I(New W ater Index)。将该指数在含不同水体类型的遥感影像上进行实验,均获得了较好的提取效果。利用文献样本数据所作的实验表明,NW I具有很强的普适性,可用于水体信息的快速提取,且具有较高的精度。     

基于ORDB的地理空间对象模型M-L-E(S,A)改进研究

针对地理数据中空间对象概念模型,尝试利用对象-关系数据库(ORDB)的一些优势,对已有的地理数据中空间对象的M-L-E(S,A)分层模型进行了改进,实体之间可以通过类、继承等方式产生和关联,地图和图层之间、图层和实体之间采用引用方式实现连接,不再存在从属关系,实现了更大程度的共享,可以更好地体现ORDB相对于OODB或RDB对地理空间数据的表达。同时提出了该模型的形式化表达,并对空间实体、图层和地图各层次分别进行了分析讨论,提出基于ORDB的支持方式和特点,并设想了地图尺度转化从图层到实体向下层追溯的过程。     

基于GIS的入侵生物适生区预测——以桔小实蝇为例

以入侵昆虫桔小实蝇Bactrocera dorsalis(Hendel)为例,利用GIS软件结合生态位模型对入侵生物的潜在适生区进行预测,选取影响入侵生物分布的年均温、日较差、多年平均降水、高程、地形、土地利用类型等9个环境因素,利用最大熵(maxent)模型和ArcGIS的空间分析功能,对桔小实蝇的适生区进行预测.结...     

A study of a matching pixel by pixel (MPP) algorithm to establish an empirical model of water quality mapping,as based on unmanned aerial vehicle (UAV) images

Linear regression models are a popular choice for the relationships between water quality parameters and bands (or band ratios) of remote sensing data. However, this research regards the phenomena of mixed pixels, specular reflection, and water fluidity as the challenges to establish a robust regression model. Based on the data of measurements in situ and remote sensing data, this study presents an enumeration-based algorithm, called matching pixel by pixel (MPP), and tests its performance in an empirical model of water quality mapping. Four small reservoirs, which cover a mere several hundred-thousand m², in Kinmen, Taiwan, are selected as the study sites. The multispectral sensors, carried on an unmanned aerial vehicle (UAV), are adopted to acquire remote sensing data regarding water quality parameters, including chlorophyll-a (Chl-a), Secchi disk depth (SDD), and turbidity in the reservoirs. The experimental results indicate that, while MPP can reduce the influence of specular reflection on regression model establishment, specular reflection does hamper the correction of thematic map production. Due to water fluidity, sampling in situ should be followed by UAV imaging as soon as possible. Excluding turbidity, the obtained estimation accuracy can satisfy the national standard.     

利用改进的归一化差异水体指数（MNDWI）提取水体信息的研究

在对M cfeeters提出的归一化差异水体指数(NDWI)分析的基础上,对构成该指数的波长组合进行了修改,提出了改进的归一化差异水体指数MNDWI(M odified NDWI),并分别将该指数在含不同水体类型的遥感影像进行了实验,大部分获得了比NDWI好的效果,特别是提取城镇范围内的水体。NDWI指数影像因往往混有城镇建筑用地信息而使得提取的水体范围和面积有所扩大。实验还发现MNDWI比NDWI更能够揭示水体微细特征,如悬浮沉积物的分布、水质的变化。另外,MNDWI可以很容易地区分阴影和水体,解决了水体提取中难于消除阴影的难题。     

大城市居住用地扩展特征及驱动力分析——以南京市中心城区(长江以南)为例

针对城市建成区的空间异质性不能反映城市居住空间结构的问题,该文选取南京市中心城区(长江以南)2001—2007年的新增居住用地,从扩展方位和强度两方面分析空间扩展特征,以直方图和Logistic回归模型揭示主导驱动因素。结果表明东北、东南、西南方向是新增居住用地的3个主要扩展方向,分别对应仙林新市区、东山新市区和河西新城区;居住用地扩展是多种驱动因素共同作用的结果,人口和经济驱动因素对郊区居住用地增加影响显著,对主城区影响有限,自然和政策驱动因素中反映政府政策的政府建设用地规划区是最重要的主导驱动因素,其次为与小学的距离,最后为与地铁站点的距离。     

基于DEM坡度坡向算法精度的分析研究

坡度坡向是两个最基本的地形因子,目前对DEM坡度坡向计算模型和精度存在一些不同的甚至矛盾的观点,其原因在于没有区分误差来源和分析评价方法的不同.本文对DEM坡度坡向误差进行了理论分析,并通过实验数据对相关结论进行了验证.旨在澄清目前关于坡度坡向计算模型上的矛盾结论.