从等值线图形获取DAT和GRD格式的数据文件

在盆地模拟研究工作中，需要处理大量的地质数据和地质图件，一方面，随时需要把各种数据变为可视的图形；另一方面，还时常需要从图形中得到研究中所必需的数据，例如，由构造图得到研究区域的深度数据文件。本文介绍一种从等值线图形获取DAT格式和网格化GRD格式的数据文件的方法。     

基于OGR的勘测定界坐标数据格式转换方法研究

勘测定界界址点坐标交换文件是国土资源管理工作中时常用到的一种空间数据格式,具有一般文本文件易读易改的特性,但缺少专业GIS软件应用支持,需要转换为通用的GIS数据格式才能进行更广泛的应用。为尽可能简化操作难度和降低软件购置成本,本文从底层开发的角度思考,基于OGR开源类库的运行机制总结了数据转换的技术流程,在VC++环境下开发了简单易用的数据转换工具,实现了自动转换为Shapefile文件的目标,对其他格式的GIS数据转换方法研究具有一定的借鉴意义。     

运动学涡度在藏南冈底斯岩浆带中段谢通门-曲水韧性剪切带中的应用

一般剪切带主要由纯剪切和简单剪切共同作用,不同的剪切带及不同的构造位置两者所占有的比例不同。利用运动学涡度(Wk)可以定量地分析两者间的比值大小。本文通过极莫尔圆法和有限应变轴率Rs/石英c轴组构法对冈底斯岩浆带中段谢通门-曲水滑覆型韧性剪切带的运动学涡度进行了计算,两种方法获得了较为一致的结果。通过极莫尔圆法,对剪切带中的9组糜棱岩样品进行了运动学涡度计算,获得了Wk=0.73~0.96,平均值Wk=0.83。运用有限应变轴率Rs/石英c轴组构法对4个样品进行了分析,得到Wk=0.85~0.93,均值为0.88,两种方法获得了较为一致的应变结果。还根据极莫尔圆图解,计算了该韧性剪切带的减薄量S=0.09~0.35,平均减薄量为0.20。研究表明该韧性剪切带为典型的以简单剪切为主伴有部分纯剪切的一般剪切,该剪切带的形成可能与拉萨地体在中新世时从挤压到侧向伸展的转换有关。该剪切带变形特征和运动学涡度的确定深化了对藏南冈底斯地区的构造演化过程的理解,并对青藏高原中南部的地质研究具有推进作用。     

Tessellations in GIS: Part II–making changes

Abstract

We attempt to describe the role of tessellated models of space within the discipline of Geographic Information Systems (GIS) – a speciality coming largely out of Geography and Land Surveying, where there was a strong need to represent information about the land’s surface within a computer system rather than on the original paper maps. We look at some of the basic operations in GIS, including dynamic and kinetic applications. We examine issues of topology and data structures, and produced a tessellation model that may be widely applied both to traditional “object” and “field” data types. The Part I of this study examined object and field spatial models, the Voronoi extension of objects, and the graphs that express the resulting adjacencies. The required data structures were also briefly described, along with 2D and 3D structures and hierarchical indexing. The importance of graph duality was emphasized. Here, this second paper builds on the structures described in the first, and examines how these may be modified: change may often be associated with either viewpoint or time. Incremental algorithms permit additional point insertion, and applications involving the addition of skeleton points, for map scanning, contour enrichment or watershed delineation and simulation. Dynamic algorithms permit skeleton smoothing, and higher order Voronoi diagram applications, including Sibson interpolation. Kinetic algorithms allow collision detection applications, free-Lagrange flow modeling, and pen movement simulation for map drawing. If desired these methods may be extended to 3D. Based on this framework, it can be argued that tessellation models are fundamental to our understanding and processing of geographical space, and provide a coherent framework for understanding the “space” in which we exist.     

中心内缩综合元的水深自动综合模型

针对水深自动综合问题,该文在满足水深综合的特殊要求并保持综合前后水深分布空间一致性的基础上,利用Voronoi图工具,采用定性和定量分析方法,建立了相应的综合规则和控制流程,设计了一种中心内缩综合元的水深自动综合模型,并进行了实验验证。实验结果表明,该模型可以在保证水深综合质量的前提下,实现流程的自动化。     

Stability and capsizing analysis of nonlinear ship rolling in wind and stochastic beam seas

Considering the actual seaway condition, stability and capsizing of nonlinear ship rolling system in stochastic beam seas is of significant importance for voyage safety. Safe zone are defined in the phase space plan of the unperturbed Hamilton system to qualitatively distinguish ship motions as capsize and noncapsize. Capsize events are defined by solutions passing out of the safe zone. The probability of such an occurrence is studied by virtue of the random Melnikov function and the concept of phase space flux. In this paper, besides conventional wave excitation, the effect of wind load is also taken into account. The introduction of wind load will lead to asymmetry, in other words, it transforms the symmetric heteroclinic orbits into asymmetric homoclinic orbits. For asymmetric dynamical system, the orbital analytic solutions and its power spectrum are not readily available, and the technique of discrete time Fourier transformation (DTFT) is used. In the end, as verification of theoretical critical significant wave height, capsizing probability contour diagram is generated by means of numerical simulation. The contour diagram shows that these analytical methods provide reliable and predictive results about the likelihood of a vessel capsizing in a given seaway condition.     

锂光卤石X-ray衍射标准图谱

盐湖卤水提锂过程中需了解与掌握锂元素结晶析出与赋存状态,锂光卤石(LiCl·MgCl_2·7H_2O)作为重要的中间产物,其结构与种类均需鉴别,但由于缺乏锂光卤石的X-ray衍射标准图谱,使得常见的Xray衍射方法无法应用。利用相图原理,通过湿固相法制备高纯锂光卤石,然后对其进行X-ray衍射分析,从而提供锂光卤石X-ray衍射的标准图谱,为高镁锂比盐湖卤水提锂过程分析提供可靠的理论支撑。     

基于数据密度确定分布区域的方法：以TAS图解分析为例

为了客观地确定数据点投图后分布的主要区域,本文提出了一种基于数据密度确定数据主要分布区域的方法。利用该方法可以更加直观地了解数据分布,并可以作为数据清洗的预处理手段。本文基于GEOROC大数据,以全碱对硅（TAS）图解为例,进行了分析和验证。通过提取GEOROC 数据库中与TAS 图解相关的岩石样本中SiO₂、Na₂O、K₂O 和烧失量含量数据,通过数据常规清洗和归算,最终获得24 个种类合计13.3 万条有效数据。通过数据投点、分区统计和提取80% 数据的分布区域,验证了24种岩石样品与TAS图解的吻合程度。通过综合研究分析发现,有6类岩石的数据分布与TAS图解定义区域基本一致,18类岩石的数据分布与TAS图解定义区域有系统性偏差。大数据研究证明了TAS图解的不足之处,利用全碱和SiO₂作为指标,难以实现提升总体分类的准确性。