引入选权迭代的SPOT图像后方交会   总被引：2，自引：0，他引：2  

罗睿  刘建华  范东娟 《测绘学院学报》1998,(1)

介绍了选权迭代抗差估计方法的一般原理 ,讨论了在 SPOT后方交会计算中选权函数所需的残差和单位权方差的计算方法 ,测试了几种权函数的抗差性能 ,得出了丹麦法的权函数比较有利的结论 ,证明了其实用性和有效性  相似文献   

A comparative analysis of a fixed thresholding vs. a classification tree approach for operational burn scar detection and mapping     

C.C. Kontoes  H. Poilvé  G. Florsch  I. Keramitsoglou  S. Paralikidis 《International Journal of Applied Earth Observation and Geoinformation》2009

The scope of this paper is to demonstrate, evaluate and compare two burn scar mapping (BSM) approaches developed and applied operationally in the framework of the RISK-EOS service element project within the Global Monitoring for Environment and Security (GMES) program funded by ESA (http://www.risk-eos.com). The first method is the BSM_NOA, a fixed thresholding method using a set of specifically designed and combined image enhancements, whilst the second one is the BSM_ITF, a decision tree classification approach based on a wide range of biophysical parameters. The two methods were deployed and compared in the framework of operational mapping conditions set by RISK-EOS standards, based either on sets of uni- or multi-temporal satellite images acquired by Landsat 5 TM and SPOT 4 HRV. The evaluation of the performance of the two methods showed that either in uni- or multi-temporal acquisition mode, the two methods reach high detection capability rates ranging from 80% to 91%. At the same time, the minimum burnt area detected was of 0.9–1.0 ha, despite the coarser spatial resolution of Landsat 5 TM sensor. Among the advantages of the satellite-based approaches compared to conventional burn scar mapping, are cost-efficiency, repeatability, flexibility, and high spatial and thematic accuracy from local to country level. Following the catastrophic fire season of 2007, burn scar maps were generated using BSM_NOA for the entirety of Greece and BSM_ITF for south France in the framework of the RISK-EOS/GMES Services Element project.  相似文献   

福建省海岛和海岸带遥感影像数据库构建与实现     

周刚  许德伟  刘贞文  杨燕明 《台湾海峡》2010,29(1):99-105

在参考ISO19115-2003遥感影像元数据标准的基础上，利用覆盖福建全境的海岛、海岸带的Landsat7和SPOT5的原始影像、校正影像以及融合影像，构建基于SQL Server2005的福建省海岛、海岸带遥感影像数据库系统，实现了遥感影像元数据与影像数据的一体化存储与管理．同时，使用VB语言的可视化特性，实现了基于用户的可视化查询与下载．本系统的研发，将为福建省海岛、海岸带研究提供一个可以共享的基础数据平台．  相似文献   

ETM与SPOT影像融合方法比较和评价——以庐山及其周边区域为例   总被引：1，自引：0，他引：1  

杨泽宇  韦玉春 《地理信息世界》2011,(5):71-76

高空间分辨率影像与多光谱影像融合,为影像处理提供了更加丰富的资源,有利于进行影像的分析和制图。本文以庐山及其周边区域的2009年5月11日Landsat ETM+与2009年5月6日SPOT 5影像数据为例,对典型的融合方法进行了对比评价。融合方法包括加权融合法,IHS变换,改进的IHS变换,高频调制融合法(频域采用Butterworth滤波器,指数滤波器),HSV变换,Brovey变换,CN变换,PC变换,Gram-Schmidt变换11种方法。评价指标为相关系数、信息熵、标准差、平均梯度、相对偏差、标准偏差。结果表明,不同的融合结果突出的侧重点不同。加权融合法、Gram-Schmidt变换,PC变换方法突出了影像的信息量丰富度、清晰度,提高空间分辨率能力。CN波谱锐化,改进的IHS变换,BW0高频调制融合,指数高频调制融合方法光谱保真度较好。改进的IHS变换,BW0高频调制融合,CN波谱锐化,指数高频调制融合法在空间分辨率及光谱保真度、清晰度、信息丰富度方面的能力较均衡。  相似文献   

2009年喀喇昆仑山叶尔羌河冰川阻塞湖及冰川跃动监测   总被引：1，自引：0，他引：1  

牛竞飞  刘景时  王迪  Kenneth Hewitt 《山地学报》2011,29(3)

在气候变化的影响下,喀喇昆仑山叶尔羌河冰川突发洪水近几年频繁发生.2009-05-09,利用中国环境减灾卫星(HJ-1A/1B)影像,对叶尔羌河上游冰川突发洪水的源头进行了动态监测.在克亚吉尔冰川末端发现了冰川阻塞湖,并监测到其不断扩大.2009-08初该处冰川湖突然消失,同期影像显示其消失后,河谷中残留大量冰体,与往年情况差异巨大.结合相关水文记录及历史资料分析认为,极有可能是冰川末端突然前进(跃动)使冰川坝遭到破坏,导致冰川阻塞湖泄水.由此推测克亚吉尔冰川发生了罕见跃动现象,但需要进一步研究验证.  相似文献   

An historical empirical line method for the retrieval of surface reflectance factor from multi-temporal SPOT HRV,HRVIR and HRG multispectral satellite imagery     

Barnaby Clark  Juha Suomalainen  Petri Pellikka 《International Journal of Applied Earth Observation and Geoinformation》2011

SPOT satellites have been imaging Earth's surface since SPOT 1 was launched in 1986. It is argued that absolute atmospheric correction is a prerequisite for quantitative remote sensing. Areas where land cover changes are occurring rapidly are also often areas most lacking in situ data which would allow full use of radiative transfer models for reflectance factor retrieval (RFR). Consequently, this study details the proposed historical empirical line method (HELM) for RFR from multi-temporal SPOT imagery. HELM is designed for use in landscape level studies in circumstances where no detailed overpass concurrent atmospheric or meteorological data are available, but where there is field access to the research site(s) and a goniometer or spectrometer is available. SPOT data are complicated by the ±27° off-nadir cross track viewing. Calibration to nadir only surface reflectance factor (ρ_s) is denoted as HELM-1, whilst calibration to ρ_s modelling imagery illumination and view geometries is termed HELM-2. Comparisons of field measured ρ_s with those derived from HELM corrected SPOT imagery, covering Helsinki, Finland, and Taita Hills, Kenya, indicated HELM-1 RFR absolute accuracy was ±0.02ρ_s in the visible and near infrared (VIS/NIR) bands and ±0.03ρ_s in the shortwave infrared (SWIR), whilst HELM-2 performance was ±0.03ρ_s in the VIS/NIR and ±0.04ρ_s in the SWIR. This represented band specific relative errors of 10–15%. HELM-1 and HELM-2 RFR were significantly better than at-satellite reflectance (ρ_SAT), indicating HELM was effective in reducing atmospheric effects. However, neither HELM approach reduced variability in mean ρ_s between multi-temporal images, compared to ρ_SAT. HELM-1 calibration error is dependent on surface characteristics and scene illumination and view geometry. Based on multiangular ρ_s measurements of vegetation-free ground targets, calibration error was negligible in the forward scattering direction, even at maximum off-nadir view. However, error exceeds 0.02ρ_s where off-nadir viewing was ≥20° in the backscattering direction within ±55° azimuth of the principal plane. Overall, HELM-1 results were commensurate with an identified VIS/NIR 0.02ρ_s accuracy benchmark. HELM thus increases applicability of SPOT data to quantitative remote sensing studies.  相似文献   

Investigating rural poverty and marginality in Burkina Faso using remote sensing-based products     

《International Journal of Applied Earth Observation and Geoinformation》2014

Poverty at the national and sub-national level is commonly mapped on the basis of household surveys. Typical poverty metrics like the head count index are not able to identify its underlaying factors, particularly in rural economies based on subsistence agriculture. This paper relates agro-ecological marginality identified from regional and global datasets including remote sensing products like the normalized difference vegetation index (NDVI) and rainfall to rural agricultural production and food consumption in Burkina Faso. The objective is to analyze poverty patterns and to generate a fine resolution poverty map at the national scale. We compose a new indicator from a range of welfare indicators quantified from Georeferenced household surveys, indicating a spatially varying set of welfare and poverty states of rural communities. Next, a local spatial regression is used to relate each welfare and poverty state to the agro-ecological marginality. Our results show strong spatial dependency of welfare and poverty states over agro-ecological marginality in heterogeneous regions, indicating that environmental factors affect living conditions in rural communities. The agro-ecological stress and related marginality vary locally between rural communities within each region. About 58% variance in the welfare indicator is explained by the factors of rural agricultural production and 42% is explained by the factor of food consumption. We found that the spatially explicit approach based on multi-temporal remote sensing products effectively summarizes information on poverty and facilitates further interpretation of the newly developed welfare indicator. The proposed method was validated with poverty incidence obtained from national surveys.  相似文献   

基于稀少控制点的SPOT5卫星立体条带影像的生产应用研究   总被引：2，自引：0，他引：2  

郑福海  王铁军  袁晓宏 《地理信息世界》2010,8(1):84-87

随着相关技术的发展,高分辨率卫星遥感影像在测绘产品生产中的应用越来越广泛和深入。本文主要通过西部无图区测图的应用实践,讨论利用有理多项式方法、基于稀少控制点纠正的SPOT5HRS立体条带影像的测图生产情况,并对DLG、DEM等产品进行精度检测;同时与传统的航摄方法进行对比,分析其生产效率等情况。  相似文献   

单侧控制条件下SPOT5 HRG影像的定向试验     

王铁军  孙洪双  马治  郑福海 《地理信息世界》2010,8(6)

高分辨率卫星影像已经成为获取地理信息的重要数据源,而其定向是一项关键技术。本文利用单侧不同数量及分布的控制点对SPOT5 HRG影像进行了定向试验,探讨了在单侧控制条件下SPOT5 HRG影像的定向精度情况,为地面控制点获取较困难地区的影像定向提供了一条参考途径。  相似文献   

基于SPOT NDVI的祁连山草地植被覆盖时变化趋势分析   总被引：1，自引：0，他引：1  

戴声佩  张勃  王海军  王亚敏  李丹  王兴梅 《地理科学进展》2010,29(9)

基于RS、GIS技术和SPOT VGT-NDVI数据,运用累积平均法、均值法、趋势线分析法和影像差异法,分析了祁连山草地植被覆盖在时问和空间上的变化特征,并用Hurst指数动态预测祁连山草地植被覆盖未来变化趋势.结果表明:①1999-2007年祁连山草地植被NDVI呈缓慢增加趋势.典型草原和平原草地植被年均NDVIv和生长期NDVIg增加速率高于高寒草甸草地和沙漠草地.祁连山草地植被NDVI增加和减少的面积分别为69776 km2和15928 km2,植被NDVI增加的区域分布在冷龙岭、拉脊山、大通山、达坂山、青海南山、走廊南山、托来山、托来南山等地区,减少的区域分布在乌鞘岭、大通河、石羊河、黑河、北大河、疏勒河等河流河谷以及青海湖周边地区.②祁连山草地植被NDVI年内月和旬变化曲线均呈单峰型.③冷龙岭、宗务隆山、青海南山、镜铁山、拉脊山、乌鞘岭、大通河、黑河、北大河、疏勒河等河流河谷以及青海湖周边等地区未来草地植被覆盖有改善的趋势:走廊南山、托来山、托来南山、大通山以及湟水、石羊河等河流河谷地区未来草地植被覆盖有退化的趋势.沙漠草地、高寒草甸草地未来有改善的趋势;而典型草原和平原草地未来则有退化的趋势.  相似文献