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991.
数字化测绘技术范式的形成及其影响 总被引:1,自引:0,他引:1
范式是指导整个研究集体科学共同体进行科学研究的研究纲领和行动准则。本文对数字化测绘技术范式的形成进行阐述 ,并研究其基本特征及影响 相似文献
992.
在 1:2 50 0 0 0地图数据库生僻汉字统计的基础上 ,通过生僻汉字的编码、字模的制作、代码的编制、输入法的生成以及矢量汉字的使用等 ,提出了在GBK的基础上进行再扩展的技术和方法 ,从而解决了数字制图中生僻汉字处理的问题。 相似文献
993.
Y. Ishikawa 《GeoJournal》2000,52(3):189-194
Japanese geography studies are now being greatly affected by the rapid development of geographical information systems (GIS). Unfortunately, there has been little response from Japanese population geographers to this movement. Is GIS a welcome or an unwelcome guest? After discussing the significance of employing GIS, this article introduces some recent papers that used GIS in the field of population geography on such issues as mortality mapping, migration analysis, and household studies. Then, the two promising population-related topics of married one-person households and fertility are discussed. The ability of GIS to greatly facilitate analysis, which previously needed much time and energy, can be an encouraging stimulus of innovation in studies of current population geography. Therefore, GIS is clearly a welcome guest, although it is too wishful to think that its use would lead directly to a revitalization of contemporary population geography studies. 相似文献
994.
This paper addresses the problem of classifying minerals common in siliciclastic and carbonate rocks. Twelve chemical elements are mapped from thin sections by energy dispersive spectroscopy in a scanning electron microscope (SEM). Extensions to traditional multivariate statistical methods are applied to perform the classification. First, training and validation sets are grown from one or a few seed points by a method that ensures spatial and spectral closeness of observations. Spectral closeness is obtained by excluding observations that have high Mahalanobis distances to the training class mean. Spatial closeness is obtained by requesting connectivity. Second, class consistency is controlled by forcing each class into 5–10 subclasses and checking the separability of these subclasses by means of canonical discriminant analysis. Third, class separability is checked by means of the Jeffreys–Matusita distance and the posterior probability of a class mean being classified as another class. Fourth, the actual classification is carried out based on four supervised classifiers all assuming multinormal distributions: simple quadratic, a contextual quadratic, and two hierarchical quadratic classifiers. Overall weighted misclassification rates for all quadratic classifiers are very low for both the training (0.25–0.33%) and validation sets (0.65–1.13%). Finally, the number of rejected observations in routine runs is checked to control the performance of the SEM image acquisition and the classification. Although the contextual classifier performs marginally best on the validation set, the simple quadratic classifier is chosen in routine classifications because of the lower processing time required. The method is presently used as a routine petrographical analysis method at Norsk Hydro Research Centre. The data can be approximated by a Poisson distribution. Accordingly, the square root of the data has constant variance and a linear classifier can be used. Near orthogonal input data, enable the use of a minimum distance classifier. Results from both linear and quadratic minimum distance classifications are described briefly. 相似文献
995.
Seismic hazard within juvenile rift systems ismodelled by a semi-statistical procedure based onfault segmentation theory. Fault segmentationprovides the physical basis for strong earthquakerecurrence in regions undergoing extension, andtherefore, it may control the position and size of rupture areas for future events. The computercode FRISK (McGuire, 1978) is applied to calculateprobabilistic estimates of ground motion parameters. Six normal fault segments, on average 25 km long, aremodelled as the earthquake sources within the Gulf ofEvia Rift, Central Greece. The position and length ofsegments have been determined from image processing ofremotely-sensed data and field work. FRISK output isdirected to a Geographical Information System (GIS)and a series of high-resolution (0.1 by 0.1 of adegree) digital maps are produced. The results for100 year acceleration (63% not to be exceeded) showa 50% increase in the seismic hazard from previouslyestimated magnitudes. Areas of maximum hazard (over0.4 g) are located on the south coast of the Gulf ofEvia between the towns of Kammena Vourla and Arkitsa. The obtained shape of Peak Ground Acceleration (PGA)contours is slightly elliptical with the long axis ofthe ellipse trending E-W, and symmetric, with respectto the rift axis. 相似文献
996.
997.
根据义敦岛弧造山带区域地层特征,将该区划分为六个构造地层带。根据区域地层的沉积演化序列和受构造改造作用程序,将该区域区地层划分为史密斯地层、有限史密斯地层和非史密斯地层三种类型。据此提出了在川西造山带地区进行1:5万、1:25万区调填图的工作方法。 相似文献
998.
造山带复理石区海底扇法填图的必要性 总被引:4,自引:1,他引:3
在造山带复理石区的新一轮地质大调查中,要求动用海底扇法填图来解决过去区调工作中有解决的问题。1:25万甘孜县辐区调的实践证明在造山带复理石区填图中海底扇法是一种比层育地层学更可行、更有效、更直观的方法。 相似文献
999.
1000.
Mineral and Lithology Mapping of Drill Core Pulps Using Visible and Infrared Spectrometry 总被引:1,自引:0,他引:1
A novel approach for using field spectrometry for determining both the mineralogy and the lithology of drill core pulps (powders) is developed and evaluated. The methodology is developed using material from a single drillhole through a mineralized sequence of rocks from central New South Wales. Mineral library spectra are used in linear unmixing routines to determine the mineral abundances in drill core pulps that represent between 1 m and 3 m of core. Comparison with X-Ray Diffraction (XRD) analyses shows that for most major constituents, spectrometry provides an estimate of quantitative mineralogy that is as reliable as that provided by XRD. Confusion between the absorption features of calcite and those of chlorite causes the calcite contents determined by spectrometry to be unreliable. Convex geometry is used to recognize the spectra of those samples that are extreme and are representative of unique lithologies. Linear unmixing is used to determine the abundance of these lithologies in each drillhole sample and these abundances are used to interpret the geology of the drillhole. The interpreted geology agrees well with conventional drillhole logs of the visible geology and photographs of the split core. The methods developed provide a quick and cost-effective way of determining the lithology and alteration mineralogy of drill core pulps. 相似文献