平面控制网四参数法坐标转换与残差内插

详细推导平面控制网四参数法坐标转换的实用公式,提出新的残差内插方法,并给出算例加以验证.     

影象灰度内插的研究

在实际的影象重采样（即象元素灰度值内插）中常用的三种方法是（1）邻近点法、（2）线性内插以及三次内插方法。本文主要研究这三种影象重采样方法之间的相对差异。为此，以不同方法重采样的灰度值之间的均方根差作为精度标志。本文推导了：一维影象灰度内播中三次样条内插、四点三次内插、线性内插邻近点法之间以及二维影象内插中双线性内插、邻近点法之间的均方根差的理论估算公式，并从实践上证明了理论估算公式的正确性。     

基准点无同步观测数据时流动点位置内插方法

动态GPS精密差分定位要求基准站和流动点在每个历元均有同步观测数据.针对个别历元流动点有观测数据,基准点没有观测数据的情况,提出了用流动点历元间差分数据作为观测值,以相近历元与基准点存在同步观测数据的流动点作为已知点,内插流动点坐标的算法,推导了相应公式,通过算例验证了算法的正确生和可行性.结果表明,内插精度与基准点存在同步观测数据时流动点与基准点差分定位精度相当.     

GIS中直线元内插点精度及对误差带的影响

基于误差传播定律,考虑参数r误差影响,推导了线元内插点的精度计算公式,讨论内插点精度对线元误差带的影响,并对影响的结果进行了分析,得到了一些有益的结论.     

TIN DEM线性内插不确定性的随机过程模型

基于随机过程模型导出了TIN DEM线性内插的随机过程模型,给出了不规则随机空间三角形的不确定性描述,讨论了TIN节点误差在线性内插中的传播问题。通过理论推导和实际算例,得到了TIN DEM线性内插点的点位方差和误差椭球半轴的解析表达式、线性内插精度最高点坐标的解析表达式,该结论与三角形的形状无关;对DEM线性外推导致精度急剧下降的必然性结论进行了理论证明;得到TIN线性内插的平均点位方差解析式,从理论上说明了本文结论的有效性。     

不规则水体断面面积及体积的计算—兼论多面函数内插模型的精度

本文以吕言的三次曲面函数内插模型为基础,推出一套计算不规则水体断面面积及其体积的封闭公式,并用实例加以验证。最后从另一侧面探讨了多面函数模型的内插精度问题。本文得到的公式同样适用于工程上的土方量及断面面积的计算。     

格网电离层模型在单频精密单点定位中的应用

基于四点内插方法建立了选点内插模型,讨论了内插过程中的两种定权方法;利用4个IGS跟踪站连续3 d的实测数据,采用单频精密单点定位方法,以坐标外符合误差为标准比较分析了两种内插模型和两种定权方法的效果.实验结果表明:两种内插模型和两种定权方法都是有效的,应用于单频精密单点定位时能够使点坐标外符合精度达到厘米级.最后,针对单频精密单点定位中电离层延迟误差的处理问题提出了具有参考性的建议.     

嫦娥三号导航相机测图能力分析及地形重建

基于立体相机成像模型并结合相机参数对嫦娥三号导航相机3维测图能力进行分析,利用摄影测量原理和误差传播定律对巡视器30 m范围内的DEM精度进行了理论分析,推导出导航相机立体影像获得的采样点精度公式,并绘制了DEM的平面精度图和高程精度图;同时使用多线程技术开发了基于导航相机立体影像的地形快速重建算法,利用多线程技术完成影像的特征匹配和密集匹配,并通过分块内插生成DEM。该技术应用于嫦娥三号任务中,有力地支持了嫦娥三号遥操作路径规划相关任务。     

关于勒让德函数的一组特殊定积分递推公式

根据勒让德函数理论的基本递推公式和基本性质,详细推导了在重力梯度调和分析中出现的一组特殊定积分的递推公式;并且指出,这组递推公式对于物理大地测量的调和分析理论也具有一定的价值.     

GIS中直线元内插点精度及对误差带的影响

基于误差传播定律，考虑参数r误差影响，推导了线元内插点的精度计算公式，讨论内插点精度对线元误差带的影响，并对影响的结果进行了分析，得到了一些有益的结论。     

基于不精确推理的GES辅助决策系统研究

介绍了地理专家系统(GES)辅助决策系统的构建原理与实现方法,讨论了GES中专家知识的表示方法与推理控制策略。系统将领域专家知识划分成不同的层次和类型,采用框架网络数据结构和产生式规则表示地理学领域专家的专门性知识与经验性知识,使知识的表示简洁易于理解。在知识的推理策略中引入不精确推理机制,保证了推理机制的实现。以乌鲁木齐河流域为试验区,阐述了流域土地合理利用规划决策专家知识的表示方法,以及专家知识表示的基本规则和系统专家知识的组织方式。     

基于人工神经元网络的空间知识表达与推理方法研究

分析了智能决策支持系统的结构,通过比较指出了基于符号的知识表达与推理方法的不足,阐述了基于神经网络的知识表达与推理的方法,并认为神经网络方法可作为智能空间决策支持系统中符号方法的替代或补充,并通过实例验证了基于神经网络的不确定空间知识表达与推理的有效性.     

应用数学模型推断地图上河流的选取程度

在评价地图的质量时,如果没有大比例尺地图相对照,传统上只能根据该图使用的地图投影、地图符号的规格化程度、制图时间、制图单位等标志间接推断,这种推断是极不可靠的。本文提出用要素分布的数学模型进行推断,并以河流为例,举出推断所用的数学模型及其使用方法,最后用实例验证,结果表明这种推断方法是可靠的。     

Despeckling of TerraSAR-X Data Using Second-Generation Wavelets

This letter presents the despeckling of synthetic aperture radar (SAR) images within the bandelet and contourlet domains. A model-based approach is presented for the despeckling of SAR images. The speckle-reduced estimate is found using the first-order Bayesian inference, and the best model's parameters are estimated using the second-order Bayesian inference. Synthetic and real images are used for evaluating the qualities of the despeckling methods. The experimental results showed that the combination of Bayesian inference and bandelet transform outperforms the contourlet-based despeckling algorithm using synthetic data and objective measurements.      

遥感图像理解专家系统中面向对象的知识表示

阐述了在遥感图像理解专家系统中，用面向对象的方法表示知识，使得图像分类效率更高     

利用本体的WFS要素语义检索研究

为了实现基于多源WFS服务要素层次的语义检索,提出了一个要素本体的五元模型。在此框架下,研究了要素本体的自动构建方法,形式化定义了要素的空间关系,并扩展了逻辑关系以及空间关系的推理规则来实现要素层次的联合推理检索,并给出了联合规则推理的要素语义检索算法。实例证明,本文方法对多源WFS的语义查询具有实际的可行性,为多源WFS服务要素的语义检索提供了一个新的方法。     

Design, analysis, and inference for studies comparing thematic accuracy of classified remotely sensed data: a special case of map comparison

Assessing thematic map accuracy is a special type of map comparison that is frequently applied to remote sensing classification problems. For map comparisons in the accuracy assessment setting, one map represents the classified output and the other map represents the true or “reference” condition. Several articles in this special issue describe state-of-the-art map comparison analysis tools that could serve to quantify accuracy of a single map. However, accuracy assessment objectives generally extend beyond describing accuracy of a single map to comparing accuracy of several maps. Consequently, interest focuses on comparing map comparison measures when these measures are used to represent accuracy. The virtual workshop emphasizes the analysis component of map comparisons, but it is also important to examine the underlying study designs generating the data input into these analyses. The study designs for accuracy comparisons implemented in remote sensing practice often investigate only a single test site, thus limiting our ability to generalize the results of these accuracy comparisons. Map accuracy comparison studies can be designed to provide stronger generalizations by incorporating experimental design principles such as replication and blocking, and identifying an experimental unit appropriate for the application. It is also important to recognize the role of statistical hypothesis testing and inference for different objectives that motivate map accuracy comparisons. Deciding which of two maps to use for a particular site can be addressed by enumerative inference and does not require hypothesis testing. For the objective of a more general comparison of classification procedures, analytic inference is appropriate and hypothesis testing plays a more prominent role.     

数字地图符号的识别和推理验证

本文根据地图要素的形态分离结果，通过相互间几何关系与拓扑关系的建立，以图论为基础，重点论述了水深符号的识别、等深线值的自动标注和形态分离与识别结果的推理验证。     

Evaluation of effectiveness of three fuzzy systems and three texture extraction methods for building damage detection from post-event LiDAR data

Building damage maps after disasters can help us to better manage the rescue operations. Researchers have used Light Detection and Ranging (LiDAR) data for extracting the building damage maps. For producing building damage maps from LiDAR data in a rapid manner, it is necessary to understand the effectiveness of features and classifiers. However, there is no comprehensive study on the performance of features and classifiers in identifying damaged areas. In this study, the effectiveness of three texture extraction methods and three fuzzy systems for producing the building damage maps was investigated. In the proposed method, at first, a pre-processing stage was utilized to apply essential processes on post-event LiDAR data. Second, textural features were extracted from the pre-processed LiDAR data. Third, fuzzy inference systems were generated to make a relation between the extracted textural features of buildings and their damage extents. The proposed method was tested across three areas over the 2010 Haiti earthquake. Three building damage maps with overall accuracies of 75.0%, 78.1% and 61.4% were achieved. Based on outcomes, the fuzzy inference systems were stronger than random forest, bagging, boosting and support vector machine classifiers for detecting damaged buildings.     

点状符号设计的推理模型

本文以地图符号的视觉变量和地图要素的表示等级为依据，详细介绍了地图设计专家系统中点状符号设计的推理模型。