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1.
Thomas A. Jones 《Mathematical Geology》1989,21(3):271-283
Three aspects of successful contouring with the computer are geologic interpretation, data, and the program or algorithm. All of these are important and must be considered jointly to combine good procedures with appropriate software, but interpretation is a critical requirement for mapping geologic variables. Several acceptable, though different, maps could be drawn with a given program and set of observations, so the map that best honors geologic concepts and interpretation is most desirable. Many computer-mapping projects are flawed because one of these three aspects is ignored.This paper points out how data handling and choice of an algorithm should be affected by geologic knowledge and interpretation, including: (a) data consisting of mixtures of populations should be handled with special methods, (b) the algorithm should allow calculation of values beyond the range of observed values, (c) mapping thickness of a unit that pinches out requires projection to negative values and special handling of zero-thickness data, and (d) mapping structure on two related horizons requires that the surfaces be dealt with jointly. 相似文献
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为了实现第四纪地质三维地质模型的快速半自动构建,利用地表地形图、第四系分区图、钻孔、剖面等第四系相关数据源,按照第四系具有的严格自上而下的标准层序,依次计算每一地层的地层分区.将所有地层分区图在一张平面图上进行叠加分析,得到平面分区求交后的碎小多边形集合即地层二维子面模板库.从二维子面模板库中提取各个地层所包含的子面,并利用钻孔、剖面上相应地层的高程样本数据插值得到地层的三维顶面和底面模型,进行拓扑处理建立三维地质模型.该方法完全参照第四系三维地质填图工作的基本流程,引入二维子面模板库的概念,通过将三维地层面构建分解为地层平面分布各子区域构建和地层子面高程计算两个部分,将三维建模过程中大量计算工作转化到二维平面中完成,在保证三维地质模型精度的前提下,大大提高了建模的效率. 相似文献
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Some commonly used interpolation algorithms are analyzed briefly in this paper. Among all of the methods, biharmonic spline
interpolation, which is based on Green’s function and proposed by Sandwell, has become the mainstream method for its high
precision, simplicity and flexibility. However, the minimum curvature method has two flaws. First, it suffers from undesirable
oscillations between data points, which is solved by interpolation with splines in tension. Second, the computation time is
approximately proportional to the cube of the number of data constraints, making the method slow for situations with dense
data coverage. Focusing on the second problem, this paper introduces the moving surface spline interpolation method based
on Green’s function, and the interpolation error equations are deduced. Because the proposed method only chooses the nearest
data points by using the merge sort algorithm for interpolating, the computation time is greatly decreased. The optimal number
of the nearest points can be determined by using the interpolation error estimation equation. No matter how many data points
there are, this method can be implemented without difficulty. Examples show that the proposed method can obtain high interpolation
precision and high computation speed at the same time. 相似文献
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The purpose of the study reported here is to assess whether it may in some circumstances be useful and appropriate to use a parent material (PM) soil chemistry mapping method developed for national soil chemistry data to portray spatial variation in urban soil chemistry data in Great Britain. Analysis of variance (ANOVA) of the urban soil data suggests that spatial interpolation of soil ambient background concentrations (ABCs) using PM classified soil data may be justified for those elements with strong geogenic control. The PM soil chemistry mapping method for urban soil data is demonstrated using data from the Northampton urban area, in the English Midlands. Geometric mean (GM) and inverse distance weighting (IDW) interpolations based on the nearest four topsoil samples were evaluated. Independent validation indicated that for As, Cr, Fe and to a lesser extent K, which all exhibit relatively strong geogenic control in the Northampton urban area: (i) the PM soil chemistry mapping method is more accurate and effective than the conventional IDW grid mapping and (ii) PM soil chemistry mapping based on the average of the nearest four Lne element concentrations is more accurate than mapping based on IDW values calculated from the nearest four Lne element concentrations. The variation in effectiveness of the methods can be explained by the fact that PM exerts a significant control on As, Cr, Fe and K in the Northampton area whereas anthropogenic inputs appear to be the dominant control on the spatial variation of Pb, especially at high concentrations. The PM mapping method would be expected to work efficiently in other urban areas and for those elements where a significant proportion of the variation can be explained by PM. 相似文献
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With increasing pressure for development on one of California's greatest natural resources, her coastline, comprehensive land-use
planning becomes a necessity. One aspect of land-use planning is effective geologic mapping for the delineation of geologic
hazards. Geologists from the California Division of Mines and Geology undertook an evaluation of the feasibility of local
government implementation of the geologic policies in the 1975 California Coastal Plan, a plan designed to facilitate and
direct comprehensive coastal land-use planning. Operating under restrictions similar to those that would be encountered by
local agencies attempting to implement the policies, the Division of Mines and Geology personnel applied the geologic guidelines
to two areas in Mendocino County on the northern coast of California. Using limited data and reconnaissance mapping techniques,
reports and maps were prepared which delineated the geologic hazards that should be considered in coastal land-use planning.
It was apparent from the two studies that the types and detail of data required for the implementation of the geologic policies
of the Coastal Plan could be developed by local agencies only by augmenting their staffs to include trained geologists or
by using the services of outside consultant geologists.
Paper based on data collected for California Division of Mines and Geology Open-File Reports. 相似文献
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Common features of models for interpolation, consistent with a finite number of inequality constraints on the range of values of a variablez, are discussed. A method based on constrained quadratic minimization yielding kriging estimates when no constraints exist, is presented. A computationally efficient formulation of quadratic minimization is obtained by using results on duality in quadratic programming. Relevant properties of the optimal interpolator are derived in a simple, self-contained way. The method is applied to mapping of horizon depth and estimation of thickness of an oil-bearing formation. 相似文献
9.
Evaluation of Interpolation Accuracy of Neural Kriging with Application to Temperature-Distribution Analysis 总被引：8，自引：0，他引：8
An interpolation method based on a multilayer neural network (MNN), has been examined and tested for the data of irregular sample locations. The main advantage of MNN is in that it can deal with geoscience data with nonlinear behavior and extract characteristics from complex and noisy images. The training of MNN is used to modify connection weights between nodes located in different layers by a simulated annealing algorithm (one of the optimization algorithms of the network). In this process, three types of errors are considered: differences in values, semivariograms, and gradients between sample data and outputs from the trained network. The training is continued until the summation of these errors converges to an acceptably small value. Because the MNN trained by this learning criterion can estimate a value at an arbitrary location, this method is a form of kriging and termed Neural Kriging (NK). In order to evaluate the effectiveness of NK, a problem on restoration ability of a defined reference surface from randomly chosen discrete data was prepared. Two types of surfaces, whose semivariograms are expressed by isotropic spherical and geometric anisotropic gaussian models, were examined in this problem. Though the interpolation accuracy depended on the arrangement pattern of the sample locations for the same number of data, the interpolation errors of NK were shown to be smaller than both those of ordinary MNN and ordinal kriging. NK can also produce a contour map in consideration of gradient constraints. Furthermore, NK was applied to distribution analysis of subsurface temperatures using geothermal investigation loggings of the Hohi area in southwest Japan. In spite of the restricted quantity of sample data, the interpolation results revealed high temperature zones and convection patterns of hydrothermal fluids. NK is regarded as an interpolation method with high accuracy that can be used for regionalized variables with any structure of spatial correlation. 相似文献
10.
针对根据一系列属性等值线剖面/断面数据进行三维空间插值问题,笔者提出一种基于距离场的三维空间属性插值方法。首先,根据对应属性等值线轮廓生成三维等值面;然后,构建属性等值面的三维距离场;最后,对于空间内任意点属性,根据其两侧等值面的距离场数据进行线性插值求取,从而生成整个三维空间内的属性场模型。将该方法应用于某铜矿区的可控源音频大地电磁法(CSAMT)剖面数据,在已知视电阻率等值线剖面的基础上,插值得到三维空间的视电阻率场,可用于揭示地下空间物性分布和预测隐伏矿体等。 相似文献
11.
利用测井曲线绘制煤岩层真厚对比图 总被引：2，自引：0，他引：2
采用三次样条函数拟合测井数据，并使用新的采样间隔对其进行采样，将采样数据映射到真厚的钻孔柱状图上，从而绘制出真厚对比图。实际编程中，为保证其拟合精度及计算效率，实际采用的计算步长一般为本层厚度加上下扩展10m。选择采样间隔时，可对测井曲线进行抽稀，以减小数据占用的空间。该方法的使用解决了长期以来地质与测井对比图工作分离、结论出现差异的问题。 相似文献
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人工神经网络在识别浅覆盖区地质体中的应用 总被引：1，自引：1，他引：1
WANG Da-yong HAO Li-bo LU Ji-long College of GeoExploration Science Technology Jilin University Changchun China 《吉林大学学报(地球科学版)》2006,(Z2)
利用水系沉积物资料识别浅覆盖区地质体,对于提高区域地质填图质量具有重要意义。神经网络为解决此问题提供了新的途径。依据浅覆盖区基岩和其对应的水系沉积物在化学成分上的继承关系,以内蒙古四子王旗浅覆盖区为例,阐述了运用BP神经网络模式识别地质体的原理和方法,并识别出了化学成分相近的浅覆盖层下地质体。该方法可广泛应用于浅覆盖区地质填图。 相似文献
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因为克里金插值方法考虑了样本的空间统计特征而被广泛应用于地层建模。但对于地层尖灭、缺失等不连续地层情况,常用的克里金方法（如普通克里金方法）通常给出较为平滑的地层厚度估计结果,在地层分布边缘的局部范围内与实际情况相差较大。针对不连续地层,提出一种采用指示克里金和普通克里金相结合的地层厚度估计方法。该方法首先采用指示克里金方法估计地层分布范围,然后采用普通克里金方法估计分布范围内的地层厚度,并根据估计标准差来评价地层厚度的不确定性。将提出的方法应用于上海长江隧道的地层建模,通过交叉验证,证明了该方法在地层分布边缘的局部范围内能明显改善地厚度估计结果,标准差降低了15%～18%,得到了比普通克里金和线性插值方法更接近真实情况的地层厚度估计值。 相似文献
14.
In addition to spatial distribution of groundwater-flow parameters, aquifer properties of location and shape are also significant for assessing groundwater resources because they strongly affect water flow. We present a selection of geologic data suitable for aquifer analysis, a mathematical method of processing them, and a combination of several maps produced by it. The data used in the analysis are typically obtained by borehole investigation. Our targets are the areas underlain by geologic bodies with different ages and lithologies; the spatial correlation structures of geologic data over the areas tend to change locally. The processing method should be a versatile one that is applicable to areas where geostatistical stationarity is not satisfied. The aquifer analysis consistent with that requirement consists of two steps: the first is the transformation of screen locations, locations of sand and gravel layers, and resistivity by electric logging into indicator values, and the second is three-dimensional interpolation of these using the optimization principle method to produce three kinds of distribution models. A stochastic simulation is also used for modeling the resistivity distribution. The three distribution models are integrated to generate a value for evaluating the possibility of aquifer existence. A case study of an alluvial coastal plain, situated in southwest Japan, describes an aquifer model that contains three permeable layers. Each layer has about 10-m thickness and is lens shaped. To confirm the validity of the model, we have drilled two wells that reached one of the middle and bottom permeable layers, observing the water level change. Low correlation of the temporal changes of levels between the wells indicates that the two layers are hydrologically independent of each other. Additionally, groundwater-flow patterns have been estimated by transforming the simulation model parameter into hydraulic conductivity through a simple function and using a finite difference method for flow analysis. The procedure proposed by this study can be applied to other areas by changing the weights assigned to each geologic and geotechnical factor in the generation of the coefficient for aquifer existence, considering the reliability of each factor and hydrologic properties of study area. 相似文献
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岩石断裂表面的分形模拟 总被引：2，自引：0，他引：2
根据岩石断裂表面粗糙度所具有的统计自仿射分形的特征,提出了改进的自仿射分形插值的概念。运用改进的自仿射分形插值方法,根据实测岩石断裂表面粗糙度数据,对岩石断裂表面粗糙形态进行了分形模拟,给出了二元分形插值数学模型。将以不同数量的观测数据模拟出的插值曲面与实际测量的岩石断裂表面相比较,得出了不同数量信息点的模拟精度,它们之间的关系曲线显示为幂函数关系的规律。这就意味着不仅可以得到模拟结果,还可以得到模拟结果的估计精度。运用少量已知数据值,模拟出未知曲面,给出了由局部模拟整体的方法这对于根据少量数据研究、模拟和直观显示复杂物体的几何形态,如地形地貌、断层表面和材料裂隙表面,具有重要的应用意义。 相似文献
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三维地质建模中的多源数据融合技术与方法 总被引：2，自引：0，他引：2
建模数据多源性是三维地质建模最大的特点,模型构建的关键是将这些数据有效地融合以提高模型的精度和可靠性。首先统一地理、地质、物探、化探、遥感、钻探、采矿等建模数据的坐标系和比例尺,构建原始资料数据库。然后运用等高线数据构建数字高程模型（DEM）面,以DEM面为载体实现了地表填图路线PRB（point-routing-boundary）数据、矢量地质图、栅格地质图、遥感影像图等地表地质数据的有效融合;在已有地表地质数据和地下地质数据约束的条件下,通过约束及离散光滑插值技术实现了地表地质数据和地下地质数据的融合;根据已有建模数据确定合理的建模单元,对数据库中的点、线、面、体等数据进行归类,构建与建模单元一致的原始资料数据库。最后在原始资料数据库中,以高精度地质数据为约束对物探数据进行地质解译,综合已有建模数据,并考虑地质体的三维空间展布,实现了不同精度数据之间的融合;以主要建模数据构建初始地质界面,以高精度建模数据对已构建的初始地质界面进行约束,实现了主要建模数据与次要建模数据的融合。其中,点对线约束、点（线）对面约束、面对面约束等约束建模技术在建模数据融合过程中起重要作用。 相似文献
17.
Interpolation for geochemical surface reconstruction incorporating topographic catchment definitions
Geochemical surfaces are reconstructed by interpolating geochemical measurements obtained from stream-water and stream-sediment samples. The geographical region that influences (and therefore is represented by) the value of a geochemial sample is its topographic catchment area. However, standard convention is to treat and to record the stream sample in the database as a point location, and to reconstruct geochemical surfaces utilizing conventional point interpolation procedures. These interpolation procedures assume, generally, that a data point exerts geographical influence away from itself in all directions, and that influence declines with distance away from that data point. Conventional interpolation procedures are poorly suited for reconstructing geochemical surfaces from stream samples; they do not take into account the true geographic area that geochemical sample points represent (topographic catchments). In this paper we propose a method of interpolation which assumes that data points are representative of their topographic catchment areas. Experimental data indicates that a surface reconstruction procedure which preserves the areal character of geochemical samples provides results more meaningful than surfaces reconstructed using more conventional interpolation techniques. 相似文献
18.
J. M. Rine R. C. Berg J. M. Shafer E. R. Covington J. K. Reed C. B. Bennett J. E. Trudnak 《Environmental Geology》1998,35(4):263-277
A methodology was developed to evaluate and map the contamination potential or aquifer sensitivity of the upper groundwater
flow system of a portion of the General Separations Area (GSA) at the Department of Energy's Savannah River Site (SRS) in
South Carolina. A Geographic Information System (GIS) was used to integrate diverse subsurface geologic data, soils data,
and hydrology utilizing a stack-unit mapping approach to construct mapping layers. This is the first time that such an approach
has been used to delineate the hydrogeology of a coastal plain environment. Unit surface elevation maps were constructed for
the tops of six Tertiary units derived from over 200 boring logs. Thickness or isopach maps were created for five hydrogeologic
units by differencing top and basal surface elevations. The geologic stack-unit map was created by stacking the five isopach
maps and adding codes for each stack-unit polygon. Stacked-units were rated according to their hydrogeologic properties and
ranked using a logarithmic approach (utility theory) to establish a contamination potential index. Colors were assigned to
help display relative importance of stacked-units in preventing or promoting transport of contaminants. The sensitivity assessment
included the effects of surface soils on contaminants which are particularly important for evaluating potential effects from
surface spills. Hydrogeologic/hydrologic factors did not exhibit sufficient spatial variation to warrant incorporation into
contamination potential assessment. Development of this contamination potential mapping system provides a useful tool for
site planners, environmental scientists, and regulatory agencies.
Received: 1 April 1997 · Accepted: 4 November 1997 相似文献
19.
The multiquadric method (MQ) with high interpolation accuracy has been widely used for interpolating spatial data. However, MQ is an exact interpolation method, which is improper to interpolate noisy sampling data. Although the least squares MQ (LSMQ) has the ability to smooth out sampling errors, it is inherently not robust to outliers due to the least squares criterion in estimating the weights of sampling knots. In order to reduce the impact of outliers on the accuracy of digital elevation models (DEMs), a robust method of MQ (MQ-R) has been developed. MQ-R includes two independent procedures: knot selection and the solution of the system of linear equations. The two independent procedures were respectively achieved by the space-filling design and the least absolute deviation, both of which are very robust to outliers. Gaussian synthetic surface, which is subject to a series of errors with different distributions, was employed to compare the performance of MQ-R with that of LSMQ. Results indicate that LSMQ is seriously affected by outliers, whereas MQ-R performs well in resisting outliers, and can construct satisfactory surfaces even though the data are contaminated by severe outliers. A real-world example of DEM construction was employed to evaluate the robustness of MQ-R, LSMQ, and the classical interpolation methods including inverse distance weighting method, thin plate spline, and ANUDEM. Results showed that compared with the classical methods, MQ-R has the highest accuracy in terms of root mean square error. In conclusion, when sampling data is subject to outliers, MQ-R can be considered as an alternative method for DEM construction. 相似文献
20.
Site class mapping based on earthquake ground motion data recorded by regional seismographic network
This paper presents a methodology for site class mapping in regions without adequate geotechnical, geologic and geomorphologic data, which is prevailing in many less developed regions globally. The proposed methodology is based primarily on analysis of earthquake ground motion data recorded by regional seismographic network. Three analysis methods independently developed have been adopted with appropriate weightings, from which a continuous value of site class index ranging from 1 to 4 could be assigned to each station. Finally, a regional site class map could be developed by applying an interpolation procedure across all stations of the seismographic network of which the site classes were estimated. 相似文献