A geostatistical temporal mixture analysis approach to address endmember variability for estimating regional impervious surface distributions   总被引：1，自引：0，他引：1  

Wenliang Li 《地理信息系统科学与遥感》2016,53(1):102-121

Spectral mixture analysis (SMA) is a major approach for estimating fractional land covers through modeling the relationship between the spectral signatures of a mixed remote sensing pixel and those of the comprised pure land covers (also termed as endmembers). When SMA is implemented, endmember variability has proven to have significant impact on the accuracy of land cover fraction estimates. To address the endmember variability problem, this article developed a geostatistical temporal mixture analysis (GTMA) technique, with which spatially varying per-pixel endmember sets were estimated using an ordinary kriging interpolation technique. The method was applied to time-series moderate-resolution imaging spectroradiometer normalized difference vegetation index imagery in Wisconsin and North Carolina, United States to estimate regional impervious surface distributions. Analysis of results suggests that GTMA has achieved a promising accuracy. Detailed analysis indicates that a better performance has been achieved in less-developed areas than developed areas, and slight underestimation and slight overestimation have been detected in developed areas and less-developed areas, respectively. Moreover, while the performance of GTMA is comparable to those of phenology-based TMA and phenology-based multiple endmember TMA over the entire study area and in less-developed areas, a much better performance has been achieved in developed areas. Finally, this article argues that endmember variability may be more essential in developed areas when compared to less-developed areas.  相似文献   

数字海图水深注记的自动选取     

黄亚锋  艾廷华  张航峰 《测绘科学》2016,41(6):28-33

水深注记作为表示海底地形地貌特征的主要制图要素,它的正确选取对于保证航海安全、反映海底地貌起伏具有重要意义。针对传统的水深注记方法,该文提出一种顾及多重约束条件的水深注记选取方法。在总结水深注记综合约束条件基础上,以Vononoi图为支撑几何构造,对水深注记综合涉及的地形特征、空间分布特征、邻近特征3个方面的综合约束进行了形式化定义;借鉴人工选取的思想,在水深综合约束条件重要性排序的基础上,通过反映地形、空间分布、邻近关系等主体特征的重要水深的依次选取,以及背景水深的抽稀实现水深注记选取;最后以实测数据进行实验,验证该方法的有效性。  相似文献   

A method for finding a least-cost wide path in raster space     

Takeshi Shirabe 《International journal of geographical information science》2016,30(8):1469-1485

Given a grid of cells each having an associated cost value, a raster version of the least-cost path problem seeks a sequence of cells connecting two specified cells such that its total accumulated cost is minimized. Identifying least-cost paths is one of the most basic functions of raster-based geographic information systems. Existing algorithms are useful if the path width is assumed to be zero or negligible compared to the cell size. This assumption, however, may not be valid in many real-world applications ranging from wildlife corridor planning to highway alignment. This paper presents a method to solve a raster-based least-cost path problem whose solution is a path having a specified width in terms of Euclidean distance (rather than by number of cells). Assuming that all cell values are positive, it does so by transforming the given grid into a graph such that each node represents a neighborhood of a certain form determined by the specified path width, and each arc represents a possible transition from one neighborhood to another. An existing shortest path algorithm is then applied to the graph. This method is highly efficient, as the number of nodes in the transformed graph is not more than the number of cells in the given grid and decreases with the specified path width. However, a shortcoming of this method is the possibility of generating a self-intersecting path which occurs only when the given grid has an extremely skewed distribution of cost values.  相似文献   

熊本牡蛎(Crassostrea sikamea)多嵴和无嵴品系子二代生长性状的选择效应   总被引：2，自引：0，他引：2  

张跃环  秦艳平  张扬  李军  肖述  向志明  马海涛  喻子牛 《海洋与湖沼》2016,47(3):581-586

为了进一步检查熊本牡蛎(Crassostrea sikamea)多嵴品系及无嵴品系的连续选择反应能力,以两个品系子一代上选组为材料,以壳高为指标,按照10%选择强度,开展了两个品系子二代混合上选研究,评估了两个品系子二代选择反应、现实遗传力,计算了两个品系的遗传改进量。结果表明:两个品系仍具有较高的现实遗传力,多嵴品系遗传参数均大于无嵴品系,表现出较好的遗传改良效果。多嵴和无嵴品系幼虫期的选择反应分别为0.47、0.34,稚贝期为0.65、0.40,养成期为0.82、0.56;幼虫期的现实遗传力分别为0.27、0.19,稚贝期为0.37、0.23,养成期为0.47、0.32;幼虫期的遗传改进量分别为4.83%、3.61%,稚贝期为7.55%、5.76%,养成期为9.95%、6.47%。经过一周年的养成,多嵴品系壳高显著大于无嵴品系,两个品系现实遗传力分别为0.50、0.35,遗传改进量分别为10.13%、6.61%。由此可见,多嵴品系具有较快的生长速度,遗传改良潜力较大。本研究为熊本牡蛎遗传改良和新品系培育奠定了坚实的基础。  相似文献   

顾及分类器参数的全极化SAR图像特征选择与分类     

袁春琦  徐佳  程圆娥  许康 《测绘科学技术学报》2016,(5):507-512

全极化SAR获取的信息量远多于传统SAR,但信息量的增加并不能确保分类精度的提高,如何有效进行特征选择至关重要。针对自适应特征选择问题,提出一种顾及分类器参数的特征选择和分类方法。该方法以支持向量数为评估依据,结合遗传算法进行特征选择,并同时对分类器参数进行寻优;最后利用优选的特征集和模型参数进行分类。为验证算法的有效性,利用两组全极化数据进行了监督分类实验。实验结果表明,提出方法降低了SVM分类器对自身参数的敏感性,而且能在较少特征个数下具备良好的泛化性能,分类精度优于未经过特征选择和参数优化的方法。  相似文献   

中亚吉尔吉斯斯坦、塔吉克斯坦遥感找矿预测          下载免费PDF全文

刘丽萍  马世斌 《地质找矿论丛》2016,31(3):409-416

基于ETM,ASTER卫星遥感数据在中亚吉尔吉斯斯坦、塔吉克斯坦及我国周边地区开展的1︰100万遥感地质矿产解译,是在前人研究成果基础上,对该区进行大地构造格架遥感解析,提取区内主要断裂构造和与成(控)矿作用相关的地层、构造、岩浆岩、蚀变信息,并根据控矿地层、控矿岩体、蚀变异常与线环构造等信息建立典型矿床遥感找矿模型;以找矿模型为指导,结合矿床类型、成矿地质背景、主要控矿和成矿要素、遥感地质解译信息、遥感异常信息等多源信息对研究区进行成矿预测及战略选区。  相似文献   

The construction of extreme compositions     

Ross M. Renner 《Mathematical Geology》1995,27(4):485-497

If a geochemical compositional dataset X (n×p)is a realization of a physical mixing process, then each of its sample (row) vectors will approximately be a convex combination (mixture) of a fixed set of (l×p)extreme compositions termed endmembers. The kpoints in p-space corresponding to a specified set of k (klinearly independent endmember estimates associated with a p-variate (n×p)compositional dataset X,define the vertices of a (k–1)dimensional simplex H.The nestimated mixtures X (n×p)which together account for the systematic variation in the dataset X,should each be convex combinations of the kfixed endmember estimates. Accordingly,the npoints in p-space which represent these mixtures should be interior points of the simplex H.Otherwise, for each sample point which lies outside H,at least one of the mixture coefficients (endmember contributions) will be negative. The purpose of this paper is to describe procedures for expanding H in the situation that its vertices are not a set of extreme points for the set which represents the mixtures.  相似文献   

城市垃圾地质填埋场址的优选方法   总被引：16，自引：1，他引：15  

刘长礼  张云  王秀艳 《地球学报》1998,19(4):438-442

城市垃圾地质填埋场的选择涉及到经济,交通运输,地质环境,环境保护等因素,是一项十分复杂的工作。本文以浦东垃圾填埋场最优地段的优选为例,应用层次分析方法,阐明了城市垃圾地质填埋场址的优选方法及其过程。  相似文献   

创新政策环境对外商直接投资区位选择的影响——以珠江三角洲核心区六市为例   总被引：1，自引：0，他引：1  

彭如霞  夏丽丽  林剑铬 《地理学报》2021,76(4):992-1005

外商直接投资（FDI）企业按知识基础类型可分为解析型、合成型和象征型,从政策工具维度对珠江三角洲核心区六市2007—2016年的创新政策进行文本分析,以创新政策强度和创新政策协同度两个指标量化评估珠三角核心区六市创新政策环境,利用多项式逻辑回归模型识别和检验创新政策环境对异质性知识基础的外商直接投资企业区位选择的影响。结果表明：① 珠三角核心区六市创新政策环境时空分异显著,以2010年为时间节点创新政策强度显著提升而协同度明显降低,创新政策强度与协同度均呈楔形空间结构但二者空间异构明显;② 创新政策强度和创新政策协同度对FDI区位选择皆有显著的正效应,且随着创新政策协同度的提升区域更有可能成为解析型和合成型FDI区位选择的对象;③ 政府态度、企业进入方式和布局区位对FDI区位选择有显著影响,集聚因素中的商务服务水平对FDI区位选择的影响显著为正,而城市人口密度和集聚经济水平的影响显著为负。研究结果对地方政府实施更加本地化的创新政策吸引差异化知识基础的FDI,构建区域竞争优势带来重要启示。  相似文献   

层次分析法在四川省通江县广纳镇土地评估中的应用   总被引：5，自引：1，他引：4  

岑静  陈家玮  杨忠芳  余涛  汤奇峰  金立新 《地质通报》2008,27(2):277-285

应用层次分析法对四川省巴中市通江县广纳镇地区的土地进行了质量评估。通过分析影响各评价指标的主要因子．建立各层次结构模型和质量指数数学模型,得出地球化学综合指数,评价了该地区土地的质量状况。在此基础上．对各指标进行优化选择,比较所选的不同指标对建立土地质量评估最终结果的影响差异,进行指标筛选的探索。评价结果显示．佛驹山村的土壤质量情况较好,高坑坝村的土壤质量较差。  相似文献