一种面向对象的城市湖泊遥感提取指数

城市湖泊是城市水资源环境的核心组成部分,可对城市区域微气候产生积极的调节作用,同时能反映当地的文化底蕴特色.在当今城市化进程的影响下,城市湖泊比自然湖泊更脆弱且更易发生变化.提出了一种面向对象的城市湖泊遥感提取指数方法,并以武汉市中心城区为研究区,实现了该研究区域城市湖泊对象的一次性提取.定量统计表明,湖泊提取的准确率...     

Modeling Urban Growth Using GIS and Remote Sensing

Based on remote sensing and GIS, this study models the spatial variations of urban growth patterns with a logistic geographically weighted regression (GWR) technique. Through a case study of Springfield, Missouri, the research employs both global and local logistic regression to model the probability of urban land expansion against a set of spatial and socioeconomic variables. The logistic GWR model significantly improves the global logistic regression model in three ways: (1) the local model has higher PCP (percentage correctly predicted) than the global model; (2) the local model has a smaller residual than the global model; and (3) residuals of the local model have less spatial dependence. More importantly, the local estimates of parameters enable us to investigate spatial variations in the influences of driving factors on urban growth. Based on parameter estimates of logistic GWR and using the inverse distance weighted (IDW) interpolation method, we generate a set of parameter surfaces to reveal the spatial variations of urban land expansion. The geographically weighted local analysis correctly reveals that urban growth in Springfield, Missouri is more a result of infrastructure construction, and an urban sprawl trend is observed from 1992 to 2005.     

水稻种植面积估计的运行化遥感方法

该文提出了用高分子辨率遥感数据提取水稻种值面积本底数据和用可靠低廉的ＮＯＡＡＡＶＨＲＲ数据估计水稻种植面积变化趋方法。该方法具有运行化的特点，成功地应用于１９９４年度湖北省早稻种植面积估算。     

多源遥感数据支持下的区域性森林冠层高度估测

结合机载LiDAR数据,提出了一种改进的GLAS光斑点冠层高度地形校正模型,以校正后的GLAS光斑点作为输入样本,结合MODIS遥感影像,利用支持向量回归（SVR）的方法对研究区森林冠层高度进行分生态区估测,并利用野外调查数据和机载LiDAR冠层高度结果对估测结果进行验证。结果显示:研究区的坡度等级直接影响GLAS光斑点森林冠层高度估测精度,改进的地形校正模型可以较好的减小坡度对GLAS光斑点森林冠层高度估测的影响,模型精度RMSE稳定在3.25~3.48 m;不同生态分区的SVR模型估测精度较为稳定,其RMSE=6.41~7.56 m;与算数平均高相比,样地的Lorey's高与制图结果拟合最好,不同生态分区平均估测精度为80.3%。机载LiDAR冠层高度结果的验证平均精度为79.5%,和Lorey's高验证结果呈现较好的一致性。     

利用遥感和GIS的方法预测外来入侵物种的潜在分布

外来物种入侵已经成为人类历史上最重大的生态事件之一,它直接威胁到了包括中国在内的世界上很多国家的经济、公众健康、农业生产力和生态的完整性。该研究利用遥感和GIS的方法进行了外来入侵物种的相对适生区分析,预测了外来物种-豚草在中国的潜在分布,并在信息理论的框架下建立了一种改进的加权平均逻辑回归模型。利用logit阈值和频率统计的方法对入侵物种的生境进行相对适应性划分,减小了生物多样性数据的不对称带来的影响。     

泰国水稻种植面积月变化的遥感监测

介绍了光学和微波遥感影像相结合进行泰国水稻种植面积监测方法。泰国雨季雨量充足 ,气温适合 ,同一时间耕地上水稻的物候多样 ,每月水稻种植面积都发生变化。利用旱季的TM影像 ,获得耕地信息。同时利用TM影像覆盖的雷达区域进行非耕地去除 ,进行非监督分类 ,提取反映水稻种植不同生长期的雷达影像后向反射系数特征 ,建立各种类型的分类模型 ,采用监督分类的方法对全景雷达数据进行水稻种植情况调查 ,并分别予以识别和统计 ,反映研究区水稻月种植情况。分类结果通过类别检验和面积量算检验进行精度评价和分析。     

Assessment and Management Flash Flood in Najran Wady Using GIS and Remote Sensing

Flash flood assessment and management are necessary for municipal, urban growth planning and emergency action plans. By using the Hydrologic Engineering Centers River Analysis System software, we can model flash flood events and calculate water surface profiles over the length of the modeled stream. After collecting elevation points by using GPS method, the digital elevation model can be calculated for the study area. Najran city has main flood stream passes beside King Abdullah Road based on facts and previous works. A small study area including the mainstream of Wady Najran and King Abdullah Road has chosen as test site. The used methodology has also been proved efficiently for identifying flood inundation maps. Water extent area overlapped by 52–86% for both used methods. At discharge Q = 15 m³/s, the road needs to be protected from the flood.     

Quantitative Determination of Soil Erosion and Prioritization of Micro-Watersheds Using Remote Sensing and GIS

Soil erosion which occurs at spatially varying rate is a widespread threat to sustainable resource management at watershed scale. Thus estimation of soil loss and identification of critical area for implementation of best management practice is central to success of soil conservation programme. The present study focuses application of most widely used Universal Soil Loss Equation (USLE) to determine soil erosion and prioritization of micro-watersheds of Upper Damodar Valley Catchment (UDVC) of India. Annual average soil loss for the entire basin is 23.17 t/ha/yr; for micro-watersheds. High soil loss is observed in 345 micro-watersheds, medium in 159 micro-watersheds and low soil loss is observed in 201 micro-watersheds. It is found that, out of 705 micro-watersheds of UDVC, 453 micro-watersheds are in agreement with AISLUS suggested priority which is based on observed sediment yield, 116 micro-watersheds under predict and 136 micro-watersheds over predict the priority. Geographic Information System (GIS) is applied to prepare various layers of USLE parameters which interactively estimate soil erosion at micro-watershed level. The main advantage of the GIS methodology is in providing quick information on the estimated value of soil loss for any part of the investigated area.     

森林地上生物量遥感估测研究进展

森林生物量是衡量生态系统生产力的重要指标,也是研究森林生态系统物质循环的重要基础,其估测方法可以分为传统地面实测法、遥感监测法和综合模型法.随着生物量估测从样地研究发展到区域应用,空间尺度的增大导致宏观资料和参数的获取存在很多困难.在深入分析目前应用遥感技术估算森林生物量的方法及原理基础上,系统评述了统计模型、物理模型...     

Estimation of Light Pollution Using Satellite Remote Sensing and Geographic Information System Techniques

The primary focus of this research is to estimate light pollution in the urban and suburban regions of Pakistan with the help of satellite remote sensing (SRS) and geographic information system (GIS) techniques. Analog maps and multi-temporal nighttime images of the Defense Meteorological Satellite Program (DMSP) onboard Operational Linescan System (OLS) sensor were used in this study. A series of direct and indirect light pollution maps of the study area were generated and analyzed. The results of the study show that in the urban environment, light pollution is mainly due to artificial nightlight sources.     

Identification of Artificial Recharge Sites for Noyyal River Basin Using GIS and Remote Sensing

The water is a nature’s valuable gift to all life forms. Water quality and quantity plays a major role for the growth and development of community. Both natural and human factors influence the quality and quantity of water source. Depending upon the quality and quantity of groundwater it can be used for various purposes, such as drinking, agricultural and industrial. Due to revolution in industries and various anthropogenic sources in the past decades, groundwater has been polluted and depleted. Remote sensing and Geographical Information System (GIS) has become one of the leading tools in the field of hydrogeological science, which helps in assessing, monitoring and conserving groundwater resources. GIS technology provides suitable alternatives for efficient management of large and complex databases. In recent years, the increasing use of satellite remote sensing data has made it easier to define the spatial distribution of different groundwater prospect classes on the basis of geomorphology and other associated parameters. Analysis of remotely sensed data along with Survey of India(SOI) topographical sheets and collateral information with necessary field checks helps in generating the base line information for artificial recharge. The artificial recharge sites were identified by integrating thematic maps of geology, geomorphology, slope, drainage density and lineament density of the study area. The study focuses on the development of remote sensing and GIS based analysis and methodology for identifying artificial recharge studies in Noyyal river basin.     

Yield Estimation Model and Water Productivity of Wheat Crop (Triticum aestivum) in an Irrigation Command Using Remote Sensing and GIS

Crop yield estimation has an important role on economy development and its accuracy and speed influence yield price and helps in deciding the excess or deficit production conditions. The water productivity evaluates the irrigation command through water use efficiency (WUE). Remote sensing (RS) and geographical information system (GIS) techniques were used for crop yield and water productivity estimation of wheat crop (Triticum aestivum) grown in Tarafeni South Main Canal (TSMC) irrigation command of West Bengal State in India. One IRS P6 image and four wide field sensor (WiFS) images for different months of winter season were used to determine the Normalized Difference Vegetation Index (NDVI) and Soil Adjusted Vegetation Index (SAVI) for area under wheat crop. The temporally and spatially distributed spectral growth profile and AREASUM of NDVI (A_NDVI) and SAVI (A_SAVI) with time after sowing of wheat crop were developed and correlated with actual crop yield of wheat (Y_act). The developed relationships between A_SAVI and Y_act resulted high correlation in comparison to that of A_NDVI. Using the developed model the RS based wheat yield (Y_RS) predicted from A_SAVI varied on entire TSMC irrigation command from 22.67 to 33.13 q ha⁻¹ respectively, which gave an average yield of 26.50 q ha⁻¹. The RS generated yield based water use efficiency (WUE_YRS) for water supplied from canal of TSMC irrigation command was found to be 6.69 kg ha⁻¹ mm⁻¹.     

Assessment of Post-fire Soil Erosion Risk in Fire-Affected Watersheds Using Remote Sensing and GIS

Soil erosion is a prominent cause of land degradation and desertification in Mediterranean countries. The detrimental effects of soil erosion are exemplified in climate (in particular climate change), topography, human activities, and natural disasters. Forest fires, which are an integral part of Mediterranean ecosystems, are responsible for the destruction of above-and below-ground vegetation that protects against soil erosion. Under this perspective, the estimation of potential soil erosion, especially after fire events, is critical for identifying watersheds that require management to prevent sediment loss, flooding, and increased ecosystem degradation. The objective of this study was to model the potential post-fire soil erosion risk following a large and intensive wildland fire, in order to prioritize protection and management actions at the watershed level in a Mediterranean landscape. Burn severity and preand post-fire land cover/uses were mapped using an ASTER image acquired two years before the fire, air photos acquired shortly after the fire, and a Landsat TM image acquired within one month after-fire. We estimated pre-and post-fire sediment loss using an integrated GIS-based approach, and additionally we analyzed landscape erosion patterns. The overall accuracy of the severity map reached 83%. Severe and heavy potential erosion classes covered approximately 90% of the total area following the fire, compared to 55% before. The fire had a profound effect on the spatial erosion pattern by altering the distribution of the potential erosion classes in 21 out of 24 watersheds, and seven watersheds were identified as being the most vulnerable to post-fire soil erosion. The spatial pattern of the erosion process is important because landscape cover heterogeneity induced especially by fire is a dominant factor controlling runoff generation and erosion rate, and should be considered in post-fire erosion risk assessment.     

利用改进城市遥感生态指数的苏州市生态分析

城市的迅速发展伴随着生态环境的变化,快速掌握生态环境质量以及变化分布已成为近年来的重要研究热点.选取苏州范围内多时相Landsat影像,利用遥感生态指数(RSEI)提取绿度(NDVI)、湿度(WET)、热度(LST)、干度(NDBSI)等4项指标,并通过融入人类活动强度指标IPOI构建改进城市遥感生态指数(IRSEI)...     

Delineation and Characterization of Waterlogged Salt Affected Soils in IGNP Using Remote Sensing and GIS

The India Remote Sensing data on 1:50,000 scale revealed the occurrence of permanent waterlogging in low-lying flats and depressions of the Indira Gandhi Nahar Pariyojona (IGNP) command area. Such data also indicated seasonal dynamics of waterlogging and soil salinization (Salt efflorescence/crusting) in irrigated areas. Mixed spectral signatures of high moisture content and poor crop stand indicated the presence of shallow aquifers close to the main canal. Digital analysis facilitated some indicators for segregating such land uses, limited to optical range. Ground truth study found patchy crop stand, moist soil profile and subsurface soil salinization indicating the presence of high water table (<1.5 m). It also found fluctuating (1.5–6.0 m) water table with poor vegetative growth indicating areas sensitive to waterlogging These were classified as potential waterlogging. Moderate to high soil salinity was found at surface and at the control section (0.2–0.8 m) of soil profiles indicating initiation of secondary salinization. Coarse to medium soil texture facilitated capillary rise of salts with the advancing water table in irrigated zone. The presence of fine textured and impermeable calcium carbonate layers at a depth below the surface enhanced waterlogging and rise of water table. The preponderance of chlorides and sulfates of sodium, calcium and magnesium was found in the salinized areas. The quality of ponded water was extremely poor and unfit for its reuse. The ground water was saline in some areas but normally lies within the prescribed limit. The quality of drainage water was poor in saline depression and unsuitable for reuse. These were moderate in other areas suggesting its safe reuse if mixed with good quality water. Suitable soil and water management practices are necessary for sustainable crop production in the irrigated areas     

Estimation of Heavy-Metal Contamination in Soil Using Remote Sensing Spectroscopy and a Statistical Approach

Heavy-metal-contaminated soil is a critical environmental issue in suburban regions. This paper focuses on utilizing field spectroscopy to predict the heavy metal contents in soil for two suburban areas in the Jiangning District (JN) and the Baguazhou District (BGZ) in China. The relationship between the surface soil heavy metal contents and spectral features was investigated through statistical modeling. Spectral features of several spectral techniques, including reflectance spectra (RF), the logarithm of reciprocal spectra (LG) and continuum-removal spectra (CR), were employed to establish and calibrate models regarding to Cd, Hg and Pb contents. The optimal bands for each spectral feature were first selected based on the spectra of soil samples with artificially added heavy metals using stepwise multiple linear regressions. With the chosen bands, the average predictive accuracies of the cross-validation, using the coefficient of determination R², for estimating the heavy metal contents in the two field regions were 0.816, 0.796 and 0.652 for Cd; 0.787, 0.888 and 0.832 for Pb; and 0.906 and 0.867 for Hg based on partial least squares regression. Results show that better prediction accuracies were obtained for Cd and Hg, while the poorest prediction was obtained for Pb. Moreover, the performances of the LG and CR models were better than that of the RF model for Pb and Hg, indicating that LG and CR can provide alternative features in determining heavy metal contents. Overall, it’s concluded that Cd, Hg and Pb contents can be assessed using remote-sensing spectroscopy with reasonable accuracy, especially when combined with library and field-collected spectra.     

Integrated GIS and Remote Sensing Approach to Map Pollution in Upper Lake,Bhopal, India

Abstract

Upper Lake is the lifeline of Bhopal City, India for drinking and other water needs. In recent years, environmentalists have expressed their serious concern on deteriorating water quality of this lake. Conventional field sampling methods for monitoring lake water quality lack spatial information about the pollution in the lake. It is desirable to have spatial information about the lake for better management and control. In the present paper the remote sensing data from IRS-1C LISS III have been integrated into a GIS environment to analyse and create a pollution zone map of the Upper Lake.

Spectral reflectance analysis was carried out to find the suitability of wavelengths for determining chlorophyll‐a concentration (chl‐a), suspended solid concentration (SSC) and secchi depth (SD). Empirical models relating spectral reflectance and chl‐a, SSC and SD were developed using least square regression analysis. These models were found valid on unused samples. Chl‐a, SSC and SD distribution maps were generated using proposed models and were incorporated as datalayers in the GIS for further analysis of pollution zones. The spatial information of pollution offered by the pollution zone map could delineate regions of lake having high pollution load. The methodology employed in this work can be used for regular monitoring of the pollution in surface water bodies and serve the data needs for better management of the water quality.