基于RS和USLE的红壤丘陵区小流域水土流失量估算

采用野外调查采样、室内分析测定、遥感(RS)技术、数学模型等研究方法,以湖南省资兴市东江水库上游光河桥小流域为例,计算出了美国通用土壤流失方程(USLE)中各单项因子值,对该流域水土流失量进行了估算.结果表明:该流域的土壤可蚀性因子(K值)介于0.14～0.42 t·hm2.h.hm-2.MJ-1.mm-1之间,平均为0.27 t·hm2.h.hm-2.MJ-1,mm-1,属于中等可侵蚀性土壤;土壤侵蚀模数在0 ～3 817 t·hm-2·a-1之间,平均侵蚀模数为78 t.hm-2.a-1,处于强度侵蚀等级,流域的土壤侵蚀量达到292 266 t·a-1.     

基于WorldView影像实现暗礁识别定位

通过对WorldView遥感影像的纠正、融合、直方图拉伸、采集等处理,获得了海域内暗礁的空间位置及其数字正射影像,并根据相关资料及外业调绘数据,录入暗礁属性信息,建立暗礁的地理信息数据库,实现暗礁的识别定位。     

基于AdaBoost算法的遥感影像水体信息提取

AdaBoost算法利用每个特征构造一个简单分类器,然后将简单分类器进行训练组合成一个强分类器。算法能够充分利用每个分类器的优势并避免其劣势,得到一个最佳判别,达到提高分类精度的目的。本文利用TM影像,将影像各波段灰度、水体指数和谱间关系特征相结合,构成提取水体的强分类器,实现水体提取。实验结果表明,算法能够非常有效地、高精度地提取水体信息。     

Imagestation OrthoPro正射影像匀光实践

简述了Imagestation OrthoPro匀光原理,结合其原理分析了正射影像匀光过程中,大面积水域、屋顶等产生明显色差的原因,并用实验证明相关的改正方法,即适当调整kernel size或darken maximun参数项值,可有效避免水域等大面积亮区匀光后产生明显色差。     

基于SD-GIS的突发水污染事故水质时空模拟

将一维河流水质系统动力学模型用于水质模拟,建立了系统动力学(SD)和GIS关联的概念框架,并基于组件式GIS和SD模型开发了水污染事故水质模拟实验系统。以2005年11月发生的松花江水污染事故为例,对特征污染物硝基苯浓度的时空变化进行了动态仿真模拟。结果显示,通过建立SD和GIS的关联,能够实现水污染事故中污染物的时空分布模拟,以及基于模型参数的模型调控与情景分析,为突发水污染事故应急方案的优选提供科学、可行的依据。     

Using spectral information from the NIR water absorption features for the retrieval of canopy water content

Canopy water content (CWC) is important for mapping and monitoring the condition of the terrestrial ecosystem. Spectral information related to the water absorption features at 970 nm and 1200 nm offers possibilities for deriving information on CWC. In this study, we compare the use of derivative spectra, spectral indices and continuum removal techniques for these regions. Hyperspectral reflectance data representing a range of canopies were simulated using the combined PROSPECT + SAILH model. Best results in estimating CWC were obtained by using spectral derivatives at the slopes of the 970 nm and 1200 nm water absorption features. Real data from two different test sites were analysed. Spectral information at both test sites was obtained with an ASD FieldSpec spectrometer, whereas at the second site HyMap airborne imaging spectrometer data were also acquired. Best results were obtained for the derivative spectra. In order to avoid the potential influence of atmospheric water vapour absorption bands the derivative of the reflectance on the right slope of the canopy water absorption feature at 970 nm can best be used for estimating CWC.     

顾及双差残差反演GPS信号方向的斜路径水汽含量

给出了顾及GPS双差残差反演斜路径水汽SWV的解算流程;然后详细给出了双差残差到非差残差的转化算法,并对算法进行了改进;最后利用并址的GPS和WVR实测数据对反演SWV算法进行了验证,结果证实改进的反演算法能以优于4 mm精度近实时估算SWV值,与目前国际研究精度在同一量级。     

引黄入晋工程的桩号系统设计与应用

对于象引黄入晋工程这样的由多个混凝土建筑物紧密且“硬性”衔接而成的,高精度、超长线路工程来说,村号系统设计是一个十分重要且具有实际应用意义的问题,为了避免高斯投影误差与高程投影误差对桩号的影响,解决桩号方面由此而引起的矛盾,以及满足工程远程运营管理对桩号的要求,作者提出了在工程的勘测设计、施工和运营管理等阶段中,应分别使用设计桩号、施工桩号和管理桩号,这３种桩号就构成了超长线路工程的桩号系统。文中     

近红外波段(900—2500 nm)水吸收系数测量

根据水在红外波段强吸收且吸收能力变化大的特点,在所提出可见光波段水吸收系数测量系统基础上增设了薄层水测量装置,使得测量水层厚度可在0.04—350 mm之间变化。在此基础上对厚度为0.04—150 mm的多个厚度水层进行了吸收系数测量,并对消除杂质影响后的测量数据进行了有效整合,得到900—2500 nm波段纯水吸收系数。由于确保了各波段数据均在仪器最佳探测区间取得,所得结果精度较高,且与被普遍接受的前期研究结果相一致,可作为相关定量遥感的基础数据。     

Water-poverty relationships in the coastal town of Mbour (Senegal): Relevance of GIS for decision support

Coastal area is always a zone with complex problems. Due to the attraction they exert, are facing many social problems. Therefore, a coastal city is usually a city with problems. Its extension, caused by the influx of people from different backgrounds, creates an increased demand for services. One of the problems frequently encountered, especially in Senegal, is access to water. The problem of access to water is poorly treated, without being correlated with the urban evolution, i.e. with increasing population and demand growth. The water resource is facing numerous complications such as the lack of integrated management, integration issues at the governance level, where the local factor is often forgotten.The town of Mbour, object of our study, does not come out of that lot, being an attractive coastal city, from an African country. This indicates the need for an integrated management oriented from local to a global basis and not vice versa. The study presented in this paper indicates that a large proportion of the population has not access to a verified drinking water system and uses water from wells or standpipes. Half of the surveyed population (50%) has no access to a water supply system. The water poverty map of the town overlaps with that of the general poverty excepting few neighborhoods. This means that even areas that are not affected by poverty have a very low or poor access to water, which so far remains the perverse effect of the reform of the Senegalese water sector in 1995.