An improved approach for the production of satellite-based geospatial reference imagery     

《International Journal of Digital Earth》2013,6(2):221-239

Abstract

An innovative and practical satellite image product is described that is ideal for applications in Northern Canada because of its wide area coverage and mapping-quality features. This product is generated from a new procedure developed at the Canada Centre for Remote Sensing (CCRS) for processing Landsat 7 imagery, and by extension, imagery from other Earth Observation satellites. By working with multiple satellite passes, each containing the equivalent of multiple scenes, the new procedure could dramatically reduce the turn-around time for generating georeferenced image products, and also increase their geometric and radiometric accuracy compared to those produced by the current methods. The objective of the process has been to generate satellite image mosaics covering large areas (e.g. >500 000 km²) with uniformly distributed errors at sub-pixel resolution. The paper discusses the theoretical basis of a photogrammetric adjustment for satellite imagery and the results obtained from several tests. The process is generic, involving a sensor model, a satellite orbit model and ground control information; thus it may be easily adapted to any satellite that allows for repeat coverage with overlapping paths. By performing an adjustment to correct the satellite position and attitude data prior to the production of orthoimage products, it is possible to create a mosaic with a single resampling process which minimises both the radiometric and geometric resampling artifacts. The results from three separate tests are presented, along with a discussion of the procedures that were followed in each case. All three tests have successfully demonstrated that sub-pixel sample size errors may be consistently obtained over large areas. A by-product process developed to support the measurement of ground control point coordinates for the satellite adjustment was the automatic matching of geographic features such as lakes and islands in vector data format. This has been a significant development in that it has eliminated manual intervention in the measurement of these features in the imagery, allowing the ground control for entire passes containing several scenes to be obtained in minutes instead of hours.  相似文献   

Use of Artificial Neural Networks for Selective Omission in Updating Road Networks     

《The Cartographic journal》2013,50(1):38-51

Abstract

An important problem faced by national mapping agencies is frequent map updates. An ideal solution is only updating the large-scale map with other smaller scale maps undergoing automatic updates. This process may involve a series of operators, among which selective omission has received much attention. This study focuses on selective omission in a road network, and the use of an artificial neural network (i.e. a back propagation neural network, BPNN). The use of another type of artificial neural network (i.e. a self-organizing map, SOM) is investigated as a comparison. The use of both neural networks for selective omission is tested on a real-life road network. The use of a BPNN for practical application road updating is also tested. The results of selective omission are evaluated by overall accuracy. It is found that (1) the use of a BPNN can adaptively determine which and how many roads are to be retained at a specific scale, with an overall accuracy above 80%; (2) it may be hard to determine which and how many roads should be retained at a specific scale using an SOM. Therefore, the BPNN is more effective for selective omission in road updating.  相似文献   

利用数据点定位的矢量地理数据数字水印算法     

王奇胜  朱长青  符浩军 《测绘学报》2013,42(2):310-316

在矢量地理数据遭受数据拼接或数据更新攻击时,由于不含水印数据点过多,目前的鲁棒水印算法检测非常困难。针对这一问题,利用脆弱水印技术,提出一种基于数据点定位的矢量地理数据数字水印算法。在鲁棒水印嵌入的同时,利用矢量地理数据坐标点的特征映射生成脆弱水印信息,并根据精度要求采用量化思想进行水印嵌入,实现对每个数据点的篡改定位,从而排除不含水印数据点的干扰,实现对矢量地理数据版权信息的可靠检测。实验结果表明,提出的算法能够有效抵抗数据拼接和数据更新攻击,减少了不含水印数据对水印检测的干扰,提高了水印检测结果的正确性。  相似文献   

基于objectARX的图幅自动接边算法的实现     

苏宇 《全球定位系统》2013,(5):90-93,98

为了解决地理信息中的图形信息存在图幅问图元的接边问题,利用C#语言调用ObjectARX托管封装类进行编程,建立AutoCAD接边命令,在AutoCAD环境下调用接边命令实现自动接边,提高数字化成图的效率和数字化地图的精度。  相似文献   

高光谱端元自动确定与提取的迭代算法     

曹建农  王贝贝  何晓宁 《遥感学报》2013,17(2):248-268

针对端元提取算法依赖人工确定端元数量的问题, 提出一种端元自动确定与提取的迭代算法。首先, 通过统计分析获得像元相似性阈值, 确定候选端元判据;其次, 对候选端元进行内、外部相关性判断, 对端元光谱集进行病态矩阵规避判断;最后, 以候选端元判据为迭代终止条件, 当图像空间不存在候选端元时, 获得端元集合并确定端元数。实验结果表明, 该方法正确有效, 可以避免顺序端元提取方法的错误风险, 提高端元提取自动化程度。  相似文献   

空间球状物体的数据采集与分析   总被引：1，自引：0，他引：1  

邓德标  方源敏  赵子龙  陈志华 《测绘科学》2013,38(5):146-148

本文推导了以球心三维坐标及半径为参数的平差模型,据此设计和完成了一个球面拟合程序,能够实现球半径已知或未知这两种情况的拟合计算。程序还可批量处理多个独立球体的观测数据,进行拟合结果与设计数据的自动匹配及对比。利用该程序对模拟数据进行分析,得出一些对采集方案有指导作用的结论。  相似文献   

地电阻率观测供电干扰及自动处理方法     

庞晶源  陈俊  王晨  滕云田  赵银刚  李钟根 《地震地磁观测与研究》2013,(5):117-122

对地电阻率观测供电干扰的原理进行详细分析,针对数据处理问题进行探讨,并找出较好的处理方法.  相似文献   

基于响应面的预应力混凝土桥动力有限元模型研究   总被引：1，自引：0，他引：1  

朱彤  殷广庆 《地震学刊》2013,(6):644-650

建立了基于正交实验的响应面模型和精细有限元模型,并将其用于中华大桥的有限元模型修正,通过实测动力数据对修正后的有限元模型计算结果进行了验证。基于修正后的有限元模型,分析了预应力对预应力钢筋混凝土桥梁模态信息（频率和振型）的影响,以及单元类型对桥梁模态频率的影响。结果表明,修正后的有限元模型能够比较准确地反映桥梁实际结构的动力特性,基于响应面模型和遗传算法的修正方法可有效地用于大桥的健康监测和状态评估;预应力对预应力钢筋混凝土桥梁模态信息的影响较小,建模时可不予精确考虑;对于由多根预应力混凝土梁组成的桥梁体系,采用实体单元分析较好。  相似文献   

基于Adaboost的高分遥感影像自动变化检测方法     

陈伟锋  毛政元  徐伟铭  许锐 《地球信息科学学报》2018,20(12):1756-1767

基于监督分类的高分辨率遥感影像变化检测需要大量人工标注,且单个监督分类器难以适应高分影像中复杂多样的地表变化信息提取,检测结果中“椒盐噪声”严重、变化图斑破碎。因此,本文提出一种基于Adaboost集成算法、自动标注训练样本的变化检测方法。首先利用非监督分类方法完成变化初检,接着在初检结果中进行“非等距”区间采样自动获取均匀分布的训练样本;然后以Adaboost算法为集成框架,选择决策树桩、Logistic回归和kNN作为弱分类器,构建一种混合分类器集成系统,充分挖掘和利用高分影像中的空间信息以提升分类精度和分类器泛化能力,最后利用SLIC分割算法和空间邻域信息对像元级检测结果进行空间约束滤波,进一步提升变化检测精度。为验证本文方法的有效性,选取SPOT-5和WorldView-2影像为实验数据,结果表明本文方法能有效降低训练样本人工标注成本、提高变化检测精度。  相似文献   

1万基础地理信息数据库地形要素更新方法探讨          下载免费PDF全文

曲莉莉 《山东国土资源》2018,34(7)

该文介绍了1∶1万基础地理信息数据库地形要素更新的作业方法和地形要素更新模式，数字线划图数据更新、等高线和高程点的更新、数据库构建、成果库更新等关键技术环节，工作中的注意事项和工作安排。结合实际工作经验，指出地形要素数据标准应进一步严格对照国家相关规范，综合考虑信息完整表达、符合使用习惯等因素，更好地满足应用和图面表达美观的制图数据标准。  相似文献