机载LIDAR点云高程数据精度检核及误差来源分析

利用GPSRTK系统对点云高程数据进行质量检核,通过对检核数据的分析,得出实际测量中不同地形情况下LIDAR测高数据能达到的精度,并分析了误差的来源。     

基于ERMapper软件的QuickBird卫星影像处理实践

采用卫星遥感方法制作的数字正射影像是获取基础空间信息最快速、高效的手段,利用高精度卫星遥感成图,处理速度快、工艺简便、图像清晰,而且精度达到成图要求。本文介绍了以高分辨率的QuickBird卫星影像为研究对象,利用ERMapper图像处理系统进行图像的几何校正、全色与多光谱数据融合方法与过程。     

主成分分析法在油荧光光谱波段选择中的应用

355nm激光器发射激光入射到海水表面,激发海表面溢油的荧光光谱,运用高光谱图像降维中应用广泛的分段主成分分析算法对油荧光光谱进行波段选择。该算法把每个分段被映射到主成分的信息量的大小作为是否被选择的标准,保证了选择波段的信息丰富;通过分段分析消除了传统主成分分析的全局性引起的波段忽略问题,获得较为满意的降维效果。     

基于MapX的阵列功能的设计与实现

首先讨论了在直角坐标系和地理坐标系下阵列功能的算法原理,详细介绍了基于Delphi和MapX的地理坐标系下阵列功能的设计和算法实现过程。此功能扩展了MapInfo的数字化功能,在一定程度上提高了数字化的效率和精度。     

基于NDVI城镇土地利用变化检测探讨

通过归一化植被指数（NDVI）结合影像差值,对经过辐射校正后的1993年和2005年武汉地区TM影像进行了土地利用变化检测,与监督法分类进行比较,得出NDVI更宜于实现变化信息探测和提取。     

Year aridity index patterns in northwest China and the relationship to summer North Atlantic sea surface temperature

Aim to linking the variability of drought in northwest China to the oceanic influence of North Atlantic SSTs at the background of global warming and at the regional climate change shifting stages, year aridity index variations in northwest China and summer North Atlantic sea surface temperature （SST） variations are examined for the 44 a period of 1961-2004 using singular value decomposition （SVD） analysis. Results show that the SST anomalies （SSTA）in the North Atlantic in summer reflected three basic models. The first SVD mode of SST pattern shows a dipole - like variation with the positive center located at southwest and negative center at northeast of extratropical North Atlantic. And it strongly relates to the positive trend in AI variation in northwest China. The second coupled modes display the coherent positive anomalies in extratropical North Atlantic SST and the marked opposite trend of AI variability between north and south of Xinjiang. In addition, the lag correlation analysis of the first mode of SSTA and geopotential heights at 500 hPa variations also shows that the indication of the former influencing the latter configuration, which result in higher air temperature and less precipitation when the SSTA in the North Atlantic Ocean in summer motivated Eurasian circulation of EA pattern, further to influence the wet - dry variations in northwest China by the ocean-to - atmosphere forcing.     

Submarine canyons on the north of Chiwei Island:influenced by recent extension of the southern Okinawa Trough

Based on new multibeam bathymetric data and about 300 km long single seismic profiles, three topographic units were identified： the canyons, fractural valley and submarine terrace on the north of Chiwei Island where is a structural transition zone between the southern trough and the middle trough. The Chiwei Canyon and the North Chiwei Canyon are two of the largest canyons in the East China Sea （ECS） slope. Topographic features and architectures of them are described. The study shows that both of them are originated along faults. The evolution and spatial distribution of topographic units in the study area are controlled mainly by three groups of faults which were formed and reactive in the recent extensional phase of Okinawa Trough. The Chiwei Canyon was initia- ted during the middle Pleistocene and guided by F4 that is a N--S trending fault on the slope and F1, a large NW--SE trending fault on the trough. The pathway migration from the remnant channel to the present one of Chiwei Canyon is the result of uplift of tilted fault block that is coupled to the recent extension movements of the southern trough. The submarine terrace is detached from the ECS slope by the NEE -trending fault. The North Chiwei Canyon, developing during the late Pleistocene, is guided by FS, a N-S trending fault, diverted and blocked by the submarine terrace.     

黄海中部海岸末次冰盛期第1硬质黏土层的粒度分维特征及其环境意义

沉积物粒度分布特征是衡量沉积介质能量,判别沉积环境和水动力条件的最基本的方法之一,粒度分维是粒度的另外一个重要参数。在前人对硬黏土成因研究的基础上,选取目前具有影响力说法的典型的沉积物：湖泊相、潮滩相、风成沙、粉尘、洪泛平原、黄土等进行了分维值的计算,通过与小庙洪区钻孔的末次冰盛期第1硬质黏土的粒度分维的对比,初步探索其粒度特征。从粒度分布与分维的角度进一步印证了该区第1硬质黏土层的沉积环境为河湖相。     

VRS RTK在地籍测量中的应用与研究

为了解决地籍测量外业要求时间短、精度较高等技术问题,在理论研究的基础上,在某市城区采用了VRS RTK技术建立测量控制网.通过成果分析得知.由于基于载波相位的GPS相对定位具有较高精度,只要控制网变形可以忽略或者进行建模,则不需要进行相邻控制点的联测,因此布设VRS RTK是非常适合的,减少了传统控制网埋石造标工作量.在RTK多测站解算中,建立了由电离层、对流层和卫星轨道引起的GPS观测误差在空间和时间的相关模型,得出在人口密集或重要经济地区布设局域GPS网的设计与测量模式.