地质矿产术语分类代码在地矿点源信息系统中的应用   总被引：13，自引：1，他引：12  

汪新庆  刘刚  袁艳斌  韩志军 《地球科学》1999,24(5):529-532

论述了如何利用地质矿产术语分类代码来建立有关数据字典,如何在数据模式设计以及地质数据描述上采用这套代码,实现地质信息共享。重点论述了地在太点源信息系统中的方法和所要解决的问题。  相似文献   

基于关键对流参数分级的强对流潜势预报     

周方媛  戴建华  陈雷 《气象科技》2020,48(2):229-241

通过对上海地区1998—2009年4—9月各类强对流天气的统计分析,选取42个对流参数及其时间变量,采用逐步回归方法建立了针对各类强对流天气的0～12h潜势预报方程。在此基础上,提出了基于关键对流参数进行分级的强对流潜势预报方法,选取K指数、SI指数、PWV(大气可降水含量)指数和θsedif85(500hPa和850hPa假相当位温差)等反映大气热力和水汽条件的关键对流参数,根据对流分布情况将各对流参数分别分为3个等级,并分级建立了针对不同强对流天气的潜势预报方程。与未分级方程对比表明:基于关键对流参数分级的预报方程对雷雨大风、强雷电和所有对流等预报效果上有明显提升,采用如下组合评分更佳:雷雨大风的预报采用SI分类方程,强雷电和所有对流采用PWV分类方程。将基于关键对流参数分级的强对流潜势预报方法在数值预报模式中进行了业务应用,取得了较好效果。  相似文献   

Mapping multiple tree species classes using a hierarchical procedure with optimized node variables and thresholds based on high spatial resolution satellite data     

Yaoliang Chen  Shuai Zhao  Zhuli Xie  Erxue Chen 《地理信息系统科学与遥感》2020,57(4):526-542

ABSTRACT

Tree species distribution mapping using remotely sensed data has long been an important research area. However, previous studies have rarely established a comprehensive and efficient classification procedure to obtain an accurate result. This study proposes a hierarchical classification procedure with optimized node variables and thresholds to classify tree species based on high spatial resolution satellite imagery. A classification tree structure consisting of parent and leaf nodes was designed based on user experience and visual interpretation. Spectral, textural, and topographic variables were extracted based on pre-segmented images. The random forest algorithm was used to select variables by ranking the impact of all variables. An iterating approach was used to optimize variables and thresholds in each loop by comprehensively considering the test accuracy and selected variables. The threshold range for each selected variable was determined by a statistical method considering the mean and standard deviation for two subnode types at each parent node. Classification of tree species was implemented using the optimized variables and thresholds. The results show that (1) the proposed procedure can accurately map the tree species distribution, with an overall accuracy of over 86% for both training and test stages; (2) critical variables for each class can be identified using this proposed procedure, and optimal variables of most tree plantation nodes are spectra related; (3) the overall forest classification accuracy using the proposed method is more accurate than that using the random forest (RF) and classification and regression tree (CART). The proposed approach provides results with 3.21% and 7.56% higher overall land cover classification accuracy and 4.68% and 10.28% higher overall forest classification accuracy than RF and CART, respectively.  相似文献   

地理国情监测地表覆盖分类数据的质量控制     

王福杰 《北京测绘》2020,(5):657-660

自2016年开始,地理国情工作的重心由普查转移到监测上来。地理国情监测地表覆盖分类数据成果的各项质量指标均比普查时更严格,如何更好地做好地表覆盖分类数据质量控制工作,直接影响监测数据成果的质量水平。本文结合山东省2019年度国情监测数据成果验收工作,对地表覆盖分类数据成果质量问题进行分析探讨,并对提高地表覆盖分类数据的质量水平提出建议。  相似文献   

Automatic soil-boundary location from transect data   总被引：8，自引：0，他引：8  

R. Webster 《Mathematical Geology》1973,5(1):27-37

Spatially distributed soil data possess a short-range erratic variation, an irregular longer range pattern, and maybe multivariate. In order to reveal a pattern or meaning in them, they are usually classified by drawing boundaries. A method is described for determining boundaries automatically on transects. A small portion of a sampled transect is taken and divided about its midpoint, and Mahalanobis' generalized distance, Dor D²,between the two halves calculated from the sample data. The procedure is repeated for portions of the same length at positions one-sampling interval apart along the transect. High peaks on the resultant series of D² identify the boundaries. The length of portions is set equal to, or somewhat less than, the expected average distance between boundaries, and is determined by constructing correlograms of principal components. The lag distance over which fairly steady decay occurs is related closely to the distance between boundaries. The procedure is illustrated with data from a 6-km transect in Oxfordshire and shows good agreement with boundaries drawn by combined air-photo interpretation and field judgment. A means of extending the procedure to two dimensions is suggested.  相似文献   

前馈神经网络在矿物识别方面的应用   总被引：2，自引：0，他引：2  

席道瑛  张涛 《矿物学报》1994,14(4):335-342

本文首先介绍人工神经网络的发展现状，然后着重阐述BP人工网络的基本原理和算法，并以蓝宝石的产地识别和石榴子石分类识别作为具体实例，用此说明人工神经网络方法在矿物学中的应用，最后对识别结果及BP算法本身进行了讨论。  相似文献   

论酸性－中酸性火成岩中包体的分类与命名     

杜杨松 《现代地质》1994,8(2):127-132

本文针对在酸性－中酸性火成岩中包体分类与命名方面存在的一些问题，阐释和厘定了有关包体名称和概念的基本含义．在此基础上，对现有包体名称和概念进行了归类．根据包体的特征及其研究工作的特点，提出了包体的分类命名原则．同时，通过分析寄主岩及其包体形成的地质作用过程，系统提出了包体的成因分类．  相似文献   

草场资源分类专家系统的研究     

刘少创 《武汉大学学报(信息科学版)》1994,(1)

在分析了基于光谱特征的统计模式识别方法用于遥感图像的计算机分类的不足之后，探讨了进一步提高遥感图像分类结果精度及可靠性的途径，指出了在遥感图像的计算机自动分类过程中，综合利用遥感图像多光谱特征及光谱特征以外的辅助信息对遥感图像进行分类是解决上述问题的有效方法，并通过笔者研制的草场资源分类专家系统ＧＥＳ（ＧｒａｓｓｌａｎｄＲｅｓｏｕｒｃｅｓＣｌａｓｓｉｆｉｃａｔｉｏｎＥｘｐｅｒｔＳｙｓｔｅｍ）说明了专家系统技术用于遥感图像分类能够有效地解决分类过程中综合利用各种辅助信息的问题。  相似文献   

应用遗传算法建立地震预报的分类体系初探   总被引：6，自引：0，他引：6  

陈棋福  石耀霖 《地震》1994,(6):40-47

本文对模拟自然界生物进化过程的遗传算法和用它所建立的分类体系进行了简要介绍，并将它们应用于地震预报探索研究，建立了初步的地震预报分类体系，结果表明：采用具有自动学习和自相适应的方法，结合现有的研究成果，可以将地震活动性的时空参数结合起来综合考虑，获得较为优化的地震预报规则集。  相似文献   

动力变质岩分类命名探讨及其研究的地质意义     

游建胜 《福建地质》1994,13(2):113-119

本文根据岩石的构造和观察尺度以及其它形变特征提出了一个简明、方便的动力变质岩分类命名方案，认为所有动力变质岩可分为两大类：具有定向构造的动力变质岩和无定向构造的动力变质岩。同时介绍各动力变质岩种类并探讨动力变质岩的叠加命名法。研究动力变质岩有助于了解断裂带的力学性质及其演化过程。在对受断裂带所控制的热液矿床进行找矿勘探时，认真研究和划分动力变质岩及其分带具有重要的指导作用。  相似文献