地图信息度量方法的研究   总被引：2，自引：0，他引：2  

刘宏林 《测绘学院学报》1992,(3)

概率统计方法是最早用于确定地图信息量的方法。但是,由于它的种种不适宜性而受到越来越多的怀疑。本文通过对概率统计方法的分析评价,试图跳出概率统计方法的框框,寻找一种更为有效的测度地图信息量的方法——综合指数法。试验结果表明,这种尝试是十分有效的。  相似文献   

准噶尔盆地头屯河地区侏罗系沉积环境与构造意义     

W.施奈德  F.马丁  赵霞飞  赵永胜  龙能礼 《新疆地质》1992,(3)

准噶尔盆地头屯河地区侏罗系陆相层序包含4种沉积:(1)冲积扇平原湿地中的砾石质河流沉积(八遭湾组),其特征提示在湿地中发育了规模不同的大河道(深3—5m,宽1OOm左右)及较小的分流或决口河道(深2m以下,宽6—30m)。(2)沙质低弯度河沉积,晚三工河、早西山窑、头屯河及齐古组沉积期的河流沉积属之。其特点是河道相与河间相间的界线清楚,提示河道在某一段时期固定于平原的特定地带;河道规模受古气候和构造的制约;气候干旱化和构造抬升(如头屯河组沉积时期),侵蚀基面降低,河流动力增加,因而河流规模变大,反之变小;晚头屯河组沉积期的干旱气候存在暂时性河道。(3)三角洲前缘沉积(河口中坝),见于八道湾、三工河及喀拉扎组中。(4)开阔湖相沉积,以三工河组厚的页岩层序为代表。 砂岩成分逆向反映源区剥蚀顺序。下侏罗统富含泥质岩屑,表示天山上古生界浅变质及沉积层系被剥蚀。自下而上,碎屑中稳定矿物增加,粒度变细,反映源区由于剥蚀而后退。中—上侏罗统砂岩成分演化方向不同于下侏罗统,可能与三工河组沉积末期盆地边缘构造回春有关。在Q-F-L三角图中,侏罗系样品大都落在构造区之间,反映陆相盆地充填物的混合来源。下—中侏罗统的煤既有原地生成,亦有重要的他生类型。  相似文献   

和田河与克里雅河流域不同类型沙物质的地球化学探讨     

吴兆宇  钱亦兵 《干旱区地理》1992,15(4):71-77

本文通过对和田河和克里雅河流域不同类型沙物质的矿物和化学成分研究,揭示了河流沙、沙丘沙和地层沙的矿物成分和化学成分存在的差异,指出这种差异是有关元素及化合物(或矿物)在不同环境下具有不同地球化学行为的结果。  相似文献   

Chemical composition of saline and subsaline lakes of the northern Great Plains,western Canada   总被引：2，自引：0，他引：2  

William M. Last 《International Journal of Salt Lake Research》1992,1(2):47-76

The northern Great Plains of Canada stretch from the Precambrian Shield near Winnipeg, Manitoba, westward for ∼1,700 km to the Rocky Mountains foothills. This vast region of flat to gently rolling terrain contains a very large number of salt lakes. Major ion chemical data on ∼500 of them are available. Although the average brine (salinity, 37 ppt) is a Na⁺−SO₄ ²⁻ type of water, the lakes exhibit a wide range of salinities and ionic compositions. This diversity is confirmed by Q-mode cluster analysis; it identified thirteen major water chemistry types. Most ions display distinct trends, both spatially and with increasing salinity. All dissolved components increase with increasing salinity, but at different rates. The relative proportions of Ca²⁺ and HCO₃ ⁻+CO₃ ²⁻ ions show a strong decrease with increasing brine salinity, whereas SO₄ ²⁻ ions increase with increasing salinity. The ionic proportions of Na⁺, Mg²⁺, K⁺ and Cl⁻ exhibit no significant relationship with salinity. R-mode factor analysis of the lake water chemistry, combined with selected environmental parameters, identifies groundwater composition, climate, and the elevation of the lake within the drainage system as most important in controlling brine chemistry and salinity on a regional basis. Variability in source of ions, reaction processes and products are undoubtedly key factors in helping to explain brine chemistry of an individual basin or variation from a local perspective, but these factors are generally poorly understood and not quantified on a regional basis. Palliser Triangle Global Change Project Contribution Number 3.  相似文献   

GIS techniques and statistical models in evaluating landslide hazard   总被引：1，自引：0，他引：1  

A. Carrara  M. Cardinali  R. Detti  F. Guzzetti  V. Pasqui  P. Reichenbach 《地球表面变化过程与地形》1991,16(5):427-445

Geographical Information Systems (GIS) and numerical cartography may greatly facilitate the development and use of statistical models for the assessment of regional landslide hazard. From a small drainage basin located in Central Italy, relevant geological and geomorphological factors were collected and processed by applying GIS technology. In particular, modules were used which both generate high-fidelity digital terrain models and automatically partition the terrain into main slope-units. The resulting information was then analysed by discriminant analysis which enabled landslide hazard and risk to be evaluated in each slope-unit. Although not lacking drawbacks, the method proved to be a feasible and cost-effective approach to landslide susceptibility assessment and mapping.  相似文献   

土壤地理研究的发展     

龚子同 《地球科学进展》1991,6(3):44-49

作者围绕14届国际土壤科学大会,介绍了国际土壤分类、土壤调查制图、世界土壤和土地数字化数据库、东亚土壤地理和土壤全球变化等方面研究的最新进展,指出我国应把土壤地理研究置于全球变化的总目标下,加强中国土壤系统分类的研究,开展1∶100万土壤—土地数字化数据库的工作、建立土壤地理信息系统以及防治土壤退化保证农业的持续发展。  相似文献   

二叠纪海相碳酸盐的锶同位素演化及其意义   总被引：4，自引：0，他引：4  

卢武长  崔秉荃 《矿物岩石》1992,12(4):80-87

本文从沫阳和熊家场剖面二叠纪海相碳酸盐和玄武岩的锶同位素变化出发,讨论了碳酸盐的锶同位素组成与峨嵋山玄武岩喷发之间的关系,以及玄武岩中海相碳酸盐的锶同位素贫化原因,指出海相碳酸盐的锶同位素组成可作为了解地球构造演化的工具。  相似文献   

黄河三角洲水冰险情预警信息系统设计与分析应用探讨     

狄小春  励惠国  陈峰  唐新桥  宫汝俊  田志刚 《遥感学报》1990,(3)

本文探讨了黄河三角洲地区水冰灾情信息系统的建立方法及其应用问题。介绍了该系统的设计原则,数据结构,建立方法和程序,并对其应用进行了分析研究。该方法也适用于其它区域。  相似文献   

On the distribution of physical and chemical particle properties in the atmospheric aerosol     

Jost Heintzenberg  David S. Covert 《Journal of Atmospheric Chemistry》1990,10(4):383-397

Consideration of sources and growth dynamics of aerosols has led to the conclusion that there may be a distribution or variation of chemical composition and physical structure among atmospheric aerosol particles as a function of size, and within a narrow size range as well. A mathematical representation of these particle properties in terms of an additional dimension to the number size distribution is described. Examples of the relevance of this aspect of aerosol characterization for physical and chemical processes in the atmosphere are discussed. A review of the available techniques shows that several methods are available which can and have provided quantitative results on the distribution of particle properties. Examples of data from the literature have been selected and are presented as three-dimensional distributions illustrating the wide range of particle properties which may exist in narrow size intervals. An evaluation of these results reiterates the value of taking the distribution of particle properties in the atmosphere into account for sampling and modeling purposes.  相似文献   

空间内插方法比较   总被引：260，自引：2，他引：260  

李新  程国栋  卢玲 《地球科学进展》2000,15(3):260-265

空间内插可以分为几何方法、统计方法、空间统计方法、函数方法、随机模拟方法、物理模型模拟方法和综合方法。介绍了每一种方法的适用范围、算法和优缺点。指出没有绝对最优的空间内插方法,必须对数据进行空间探索分析,根据数据的特点,选择最优方法;同时,应对内插结果做严格的检验。开发通用空间内插软件、智能化内插以及加强相关基础研究将是空间内插研究的重点。  相似文献