基于6S模型的山区环境星影像大气校正研究

针对山区地形复杂,高程变化较大的特点,利用6S辐射传输模型建立查找表,结合研究区DEM对影像进行了大气校正。试验结果表明,校正后的影像清晰度、对比度提高了,消除了大气对NDVI的负面影响。     

大气辐射校正方法分析

阐述遥感影像的大气辐射校正的原因及目的,并以徐州地区的CBERS-02星影像数据为基础,应用软件MATLAB7.0,分析大气辐射校正的三种方法,即利用辐射传输方程求解的方法、基于地面场地数据或辅助数据进行辐射校正方法及利用波段特性进行大气辐射校正方法。其中,重点剖析利用波段特性进行大气辐射校正的方法。     

多角度NOAA卫星数据地面BRDF反射率的大气校正

本文利用连续数天的NOAA卫星数据，采用Rahman地表二向反射模型和基于地面BRDF反射率的大气校正方法反复迭代提取出多个角度大气校正后的图像，并对结果进行了分析。实验结果表明了在多角度遥感定量研究中BRDF大气校正的重要性，大气校正结果与地面实测结果相近，且迭代收敛迅速。     

基于神经网络的二类水体大气校正

以MERIS高光谱影像为数据源,根据现有大气传输模型和大气校正方法,探索了适合于内陆湖泊二类水体的高光谱遥感影像大气校正方法。在6S辐射传输模型的基础上,构建了基于神经网络的二类水体大气校正算法。通过构建输入卫星辐亮度直接提取离水反射率的模型,无需同步气溶胶参数,即可实现大气校正。对2010年8月9日的MERIS影像进行大气校正,并将校正后的遥感反射率与准同步实测离水反射率进行对比分析,结果表明,大气校正过程有效去除了大气效应的影响,经过大气校正的13个波段的平均相对误差分布在10%～40%,得到了与实测值相近的水体遥感反射率。     

以气象记录为辅助数据的TM影像大气校正方法

本文介绍一种LANDSATTM卫星影像校正方法,通过传感器校准、大气校正、地形校正等步骤获得反射率影像,卫星飞越时的大气参数是由当地气象记录的内插值导出,再以像幅内黑暗地物做调整,所用的大气传输模型为改进的Turner模型,可计算阳光直接辐照度、天光辐照度、路径亮度等参数,地形模型既可用来调整各参量随高程的变化,又可用以校正幅射的地形效应。     

一种基于阴影像元的光学遥感大气校正方法

提出一种基于6S模型 阴影像元的大气校正方法,适用于有阴影像元存在的高空间分辨率光学遥感影像。该方法从阴影像元与非阴影像元的信号差异估算气溶胶光学厚度,与暗目标方法相比,此方法避免地表反射率的假定难题。以北京市密云县的IKONOS影像对方法进行验证。在气溶胶光学厚度的估算上,该方法的估算结果与MODIS气溶胶产品基本一致,而且其结果的稳定性明显好于暗目标法。在大气校正的结果方面,针对各类地物,比较大气校正前后的光谱与同类典型实测地物光谱,结果说明大气校正能够大大恢复各类地物光谱的典型特征,这将有利于地物的识别。最后通过比较大气校正前后的NDVI发现,大气校正能够明显增大高植被覆盖区与低植被覆盖区NDVI的差别,使植被信息更加突出。     

基于FLAASH模型的MODIS1B数据的大气校正

主要介绍了FLAASH大气校正模型的主要原理及算法,并运用ENVI软件中的FLAASH大气校正模型对上海长江口地区MODIS1B卫星影像进行大气校正,对校正前后的影像进行对比分析。研究表明,MODIS1B卫星影像经过FLAASH大气校正后,较好地消除了大气影响。     

基于SPOT卫星影像的去模糊处理

用模糊区/清晰区平均反射率匹配法对SPOT 5卫星影像进行去模糊处理.首先,结合SPOT 5各波段的统计特征,从影像上识别出模糊区;然后,对影像进行非监督分类,对同一分类区内像元在模糊区和清晰区的辐射值进行比较,计算出气溶胶空间分布;最后,将气溶胶分布输入MODTRAN模型中,对影像进行大气校正.研究中将反演的气溶胶浓度分布重采样到全色波段的分辨率,用MODTRAN对全色波段进行大气校正,也取得了较好效果.研究得出模糊区/清晰区平均反射率匹配法是一种有效的去模糊处理方法,且可将处理后的影像转换得出反射率,便于不同时相遥感影像进行对比.     

基于辐射传输模型的Hyperion光谱重建应用评价

光谱重建是高光谱数据定量分析的前提,大气校正是光谱重建的关键环节。对于缺少地面同步测量的高光谱数据,大气辐射传输模型是最可行的大气校正方法。应用当前流行的大气辐射传输模型MODTRAN 4.0和6S,分别对试验区EO-1 Hyperion高光谱数据进行大气校正和光谱重建。通过对植被、粘土矿及水体3类地物光谱重建结果的对比分析,并利用统计方法计算光谱重建精度,评价大气辐射传输模型校正的效果和模型的适用性。最后,通过FLAASH模型的试验体现了高光谱数据大气校正集成化处理的优越性。     

基于FLAASH的AVIRIS高光谱影像大气校正

分析了FLAASH大气辐射传输模型的原理,并利用该模型对美国内华达州CUPRITE矿区AVIRIS高光谱影像进行了大气校正。通过对比校正前后典型地物的光谱曲线、校正后反射率曲线与USGS波谱库反射率曲线发现,大气校正消除了水汽等大气因素的影响,获得了地物反射率;校正后反射率曲线与波谱库反射率曲线相关系数达到0.92,说明利用FLAASH进行大气校正是有效的。     

阿克苏河-塔里木河水系水质污染遥感监测与评价

 采用Landsat TM数据分析了阿克苏河—塔里木河断面水质污染状况,通过波段的DN值和常规监测数据建立能反映水质状况的 污染物监测模型。结果发现,将2000年常规监测数据代入模型后,与遥感数据的结果基本吻合| 重建阿克苏河—塔里木河的连续水体 污染变化曲线,得出污染物浓度随着远离上游而增加。     

Monitoring drought dynamics in the Aravalli region (India) using different indices based on ground and remote sensing data

The hard-rock hilly Aravalli terrain of Rajasthan province of India suffers with frequent drought due to poor and delayed monsoon, abnormally high summer-temperature and insufficient water resources. In the present study, detailed analysis of meteorological and hydrological data of the Aravalli region has been carried out for the years 1984–2003. Standardised Precipitation Index (SPI) has been used to quantify the precipitation deficit. Standardised Water-Level Index (SWI) has been developed to assess ground-water recharge-deficit. Vegetative drought indices like Vegetation Condition Index (VCI) and Temperature Condition Index (TCI) and Vegetation Health Index (VHI) have been computed using NDVI values obtained from Global Vegetation Index (GVI) and thermal channel data of NOAA AVHRR satellite. Detailed analyses of spatial and temporal drought dynamics during monsoon and non-monsoon seasons have been carried out through drought index maps generated in Geographic Information Systems (GIS) environment. Analysis and interpretation of these maps reveal that negative SPI anomalies not always correspond to drought. In the Aravalli region, aquifer-stress shifts its position time to time, and in certain pockets it is more frequent. In comparison to hydrological stress, vegetative stress in the Aravalli region is found to be slower to begin but quicker to withdraw.     

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.     

Gravity Changes Before Large Earthquakes in China: 1998-2005

Although it is well known that coseismic gravity changes take place during an earthquake, previous research has not yielded convincing evidence demonstrating that significant gravity changes occur before large earthquakes. Furthermore, even if we suspect that gravity changes occur before large earthquakes, we have yet to demonstrate how to consistently observe these changes for useful earthquake forecast that would bring benefits to society. We analyzed ground gravity survey data obtained in 1998, 2000, 200...     

GNSS系统及其技术的发展研究

阐述了国际上卫星导航系统的总体发展,对美、俄、欧、中的四大全球系统,以及相关的区域系统和增强系统进行了简单的介绍,研究分析了GNSS系统及其技术的发展趋势,同时分析了我国Compass全球系统面临的机遇和挑战,并提出了我国未来工作的建议.     

“4D”技术及其应用

介绍“４Ｄ”（即数字地面模型、数字正射影像、数字栅格地图和数字线划地图）系列产品的生产流程、关键技术、及其在耕地保护、防灾减灾救灾和城市规划等方面的应用方法。     

Virtual Australia: its key elements – know,think, communicate

Abstract

Virtual Australia is not a well-defined or agreed concept. This discussion paper conceptualises Virtual Australia as a ‘virtual [digital] model containing and representing all non-trivial objects and their contextual environment – from blue sky to bedrock – in real world Australia’. It describes a scenario for Virtual Australia, one or two decades from now, in which the locations and conditions of non-trivial objects and their environment are updated automatically through a combination of remote sensing and wireless communication technologies in support of a ‘Supranet’. It then examines the concept of the ‘Supranet’ – a pervasive information network based largely on wireless technology linking the physical world to a virtual model in real time – and develops and discusses three principal characteristics of the Supranet: the ability to have or collect specific information (know); the ability to process information (think); and the ability to communicate that information. If, in the near future, any or all non-trivial devices are to some extent able to know, think and communicate, the potential for object autonomy will be realised.     

地理数据库的关系模型及其实现

本文从以图论观点分析地理实体入手,系统阐述了地理数据库关系模型的设计法和过程。作者于1984年4～9月间在微型机上设计建立了关系型地理数据库的实方验系统(RGDB)。该系统采用了本文提出的关系模型,采用了可动态扩库的子库组合结构,这种结构具有灵活性和提高空间利用率的优点。RGDB含有多种功能的数据操作命令,除了具有一般检索功能外,还能进行“开窗”选取和十分“自由”的映象选取。本文对RGDB系统的主要性能和实现途径作了扼要介绍。     

Toward seamless indoor-outdoor applications: Developing stakeholder-oriented location-based services

Location-Based Services (LBS),an emerging new business based on smartphone and mobile networks,are becoming more and more popular.Most of these LBSs,however,only offer non-seamless indoor/outdoor applications and simple applications without giving stakeholders the chance to play an active role.Our specific aim is to solve these issues.This paper presents concepts to solve these issues by expanding the Open Location Services Interface Standard (OpenLS) to allow seamless indoor/outdoor positioning and to extend the content of the services to include information recommended by stakeholders.     

基于WebGL的三维智慧管网系统的设计与实现

随着城市面貌日新月异,地下管网的建设也在持续推进,作为城市的地下“神经网络”,全天24 h保障城市的正常运转和发展。本文以实现城市管网管理系统的高可用、无插件、智能化为目标,采用“地上地下一体”“二三维一体”的设计理念,研究基于WebGL的三维智慧管网系统的关键技术,实现了管线设施管理的信息数字化、空间化与图形化。