Fortran IV program for grey-level mapping of spatial data

Afortran iv computer program for grey-level mapping of spatial data using a CDC 6600 is described. The program produces maps for irregularly distributed data in as many as 10 intensity levels which are displayed in grey tones by a lineprinter. Unlimited map size and unrestricted data input provide for as many as 5000 data points per 13-in.-wide strip of map. The program is easily modified for other installations. Examples are given of geochemical analyses of stream sediments in Northern Ireland.     

Estimating spatial correlation structures based on CPT data

Spatial correlation structures are usually used while modelling inherent uncertainty associated with soil properties. To retrieve this information a sufficient number of measurements and equal intervals between measurements or samples are always required. However, in practice, it is not usual to conduct site investigation in that way subject to a limited budget. Therefore, it is of interest to understand the possible bias created by using samples with unequal intervals. This research focuses on estimating the vertical spatial correlation structures of cone penetration tests (CPT) data conducted at a liquefaction site in Taiwan. The appropriate fitting range used in calibrating the correlation model is also discussed. The results show that cone tip resistance has larger correlation distances than that of sleeve friction. The estimated correlation distances of the CPT profiles are similar while using an equal sampling interval within a certain fitting range (denoted as the critical interval of measurements in this research). The results indicate that the effect of using different curve-fitting ranges is relatively insignificant for correlation distances of sleeve friction, whereas the correlation distances of cone tip resistance are more sensitive to different curve-fitting ranges. Moreover, the mean values of correlation distances are more constant for the equal sampling interval cases than for the unequal interval cases.     

Accounting for exhaustive secondary data into the mapping of water table elevation

This paper presents the incorporation of a digital elevation model into the spatial prediction of water table elevation in Mazandaran province (Iran) using a range of interpolation techniques. The multivariate methods used are: linear regression (LR), cokriging (COK), kriging with an external drift (KED) and regression kriging (RK). The analysis is performed on 3 years (1987, 1997 and 2007) of water table elevation data from about 260 monitoring wells. Prediction performances of the different algorithms are compared with two univariate techniques, i.e. inverse distance weighting and ordinary kriging (OK), through cross validation and examination of the consistency of the generated maps with the natural phenomena. Significantly smaller prediction errors are obtained for four multivariate algorithms but, in particular, KED and RK outperform LR and COK for 3 years. The results show the potential for using elevation for a more precise mapping of water table elevation.     

基于Global Mapper的测绘图形数据转换

Global Mapper支持多种格式的光栅、高程、矢量数据的读取与输出,并内置多种坐标投影方式。尝试挖掘其支持多种数据格式、多种投影模式的功能,快速实现测绘图形数据的转换。通过设置当前工作空间的坐标投影模式,然后打开任何其支持的、含有坐标投影信息的数据,所有数据均自动转换成当前的投影模式,最后将文件输出（另存为）为所需的格式,即可快速完成数据转换。转换的内容主要包括不同格式的DTM(Digital Terrain Model,数字地面模型)数据转换、相同格式但不同坐标投影之间的相互转换,以及卫星影像配准等     

基于ICESat数据的南极冰盖DEM插值方法比较及精度分析

南极数字高程模型(DEM)是从事南极地学和环境变化研究的基础. 内插是建立数字高程模型的重要技术点, 插值方法有多种, 根据不同的适用情况, 不同的插值方法各有优劣. 利用克里格、 距离反权、 三角网剖分、 最小曲率以及移动平均5种插值方法分别建立南极冰盖小范围区域的DEM, 通过抽取部分观测数据作为验证值对各插值方法进行了比较. 结果表明: 克里格插值方法的可靠性最好, 稳定性最高. 然后, 利用克里格插值方法, 基于ICESat测高卫星的GLA12数据建立了南极冰盖的DEM. 由于南极大陆实测数据有限, 缺乏对DEM的检核. 为了分析所建DEM的可靠性, 利用中国南极内陆冰盖考察所采集的GPS实测数据, 对所建立的DEM进行了验证分析. 结果显示, DEM在坡度较缓的南极内陆冰盖区域精度较高, 符合度在3 m以内; 距离卫星轨道越近的区域精度越高, 可达到1 m 以内. 在坡度较大, 高程变化较为显著的区域如沿海地区, 精度较低, 差距最大的点超过40 m.     

利用ERS-1/2数据生成西藏羊八井地区数字高程模型及其精度评价

干涉合成孔径雷达(InSAR)数据已被证明能生成精确的数字高程模型。本文利用欧空局2颗卫星ERS-1/2对西藏羊八井地区成像所获取的相隔仅1天2幅SAR复数影像作了干涉处理和分析,生成了DEM,并与1∶5万DEM比较,对干涉DEM的精度作了评价,并分析了其潜在的制约因素。试验证明,在西藏地区的研究中,InSAR是一种非常有效的手段,不仅可用于地图制图,而且在地球动力学、地貌环境变化等领域也有巨大的潜力。     

Accounting for spatial patterns of multiple geological data sets in geological thematic mapping using GIS-based spatial analysis

This paper presents a Geographic Information System (GIS)-based spatial analysis scheme to account for spatial patterns and association in geological thematic mapping with multiple geological data sets. The multi-buffer zone analysis, the main part of the present study, was addressed to reveal the spatial pattern around geological source primitives and statistical analysis based on a contingency table was performed to extract information for the assessment of an integrated layer. Mineral potential mapping using multiple geological data sets from Ogdong in Korea was carried out to illustrate application of this methodology. The results obtained from the case study indicated that some geochemical elements and residual magnetic anomaly dominantly affected spatial patterns of the mineral potential map in the study area and the dominant classes of input data layers were also extracted. This information on spatial patterns of multiple geological data sets around mines could be used as effective evidences for the interpretation of the integrated layer within GIS.     

基于3D WebGIS月球地质空间数据管理系统

随着空间信息技术、地学信息技术和GIS等技术的飞速发展,利用QT结合OpenGEL技术建立基于3D WebGIS月球地质空间数据管理系统。该系统包含二维成果管理系统、发布系统与三维月球研究3个子系统,实现改善月球资料信息使用效率、信息化程度与多源空间数据共享。将中国探月计划所获取的月球地形地貌、岩层、土壤、资源、环境及各种相关数据资料与研究成果,以及国外包含数据、文献、报告等月球探测的研究最新成果集成在一起,建立了中国第一个月球地质空间数据管理系统。该信息系统既包含管理和服务功能,又提供面向科研、决策的信息服务与科学的分类管理、快速检索和联机查询的功能。地质空间数据管理系统具备强大的数据综合分析能力、综合管理月球地质资料与集成数据资料成果的汇总能力,将为中国探月工程提供有力的支撑。     

大数据环境下数字填图数据集成服务技术

应用数字填图技术形成了大量地质填图图幅数据,这些数据空间结构化和非结构化特征并存,如何在网络环境下提供高效的数据服务是急需解决的一个难题。大数据技术的发展为数字填图、数据集成服务提供了一种新的途径。通过对数字填图数据特征的分析,在研究地质调查信息网格大数据处理框架的基础上,提出了结构化和非结构化数据相结合的有序化组织管理、发布与服务方法,并对关键技术进行了研究与试验,取得了良好的效果。     

Hazard mapping based on macroseismic data considering the influence of geological conditions

The object of this study is to consider directly the influence of regional geological conditions on the assessment of seismic hazard. It is assumed that macroseismic data at individual locations contain, in an average way, the influence of geological conditions.A Data Base referring to 199 historical (5) and instrumental (194, in the 1947–1993 period) events with macroseismic information in 1195 locations of Portugal was built. For any given seismic event, whenever macroseismic information was available at a location (town, village, etc.), an EMS-92 intensity value was estimated. To each one of those locations a geological unit, representing the most common type of soil, was assigned, based on the Geological Portuguese Map at a scale 1:500 000; the geological units were grouped into three categories: soft, intermediate and hard soils.The Data Base was used to determine the attenuation laws in terms of macroseismic intensity for the three different geological site conditions, using multiple linear regression analysis. The reasonability of the laws was tested by (i) checking residual distributions and (ii) comparing the map of isoseismals of important earthquakes with the isoseismals generated by the attenuation curves derived for each one of the three different soil classes, taking into consideration the soil class of each site. The main results of attenuation modeling are: high dispersion on macroseismic intensity data; all the models predict intensity values, for short hypocentral distances, lower than the ones observed; and for some important analyzed earthquakes and for the observed range of distances, the models confirm the expectancy that macroseismic intensity increases from hard to soft soil.The approach to obtain the hazard assessment at each location consisted in the use of the attenuation law specifically derived for the class of soil of that particular location. This method, which considers the influence of the regional geology, was illustrated with the mapping of hazard for the country for several return periods. Comparison with previous maps not taking into consideration the regional geological conditions emphasizes the importance of this new parameter. It can be concluded that (i) soil segmentation is clearly the cause for hazard increase in the region to the north of Lisbon, especially at sites with soft and intermediate soils as the ones in lower Tagus valley; the maximum increase on hazard is, in any case, less than one degree; (ii) when geological conditions are disregarded in the attenuation regression analysis, hazard pattern is similar to the one obtained for the case of hard soil everywhere.     

大数据环境下数字填图数据集成服务技术

应用数字填图技术形成了大量地质填图图幅数据,这些数据空间结构化和非结构化特征并存,如何在网络环境下提供高效的数据服务是急需解决的一个难题。大数据技术的发展为数字填图、数据集成服务提供了一种新的途径。通过对数字填图数据特征的分析,在研究地质调查信息网格大数据处理框架的基础上,提出了结构化和非结构化数据相结合的有序化组织管理、发布与服务方法,并对关键技术进行了研究与试验,取得了良好的效果。     

US billion-dollar weather and climate disasters: data sources, trends, accuracy and biases

This paper focuses on the US Billion-dollar Weather/Climate Disaster report by the National Oceanic and Atmospheric Administration’s National Climatic Data Center. The current methodology for the production of this loss dataset is described, highlighting its strengths and limitations including sources of uncertainty and bias. The Insurance Services Office/Property Claims Service, the US Federal Emergency Management Agency’s National Flood Insurance Program and the US Department of Agriculture’s crop insurance program are key sources of quantified disaster loss data, among others. The methodology uses a factor approach to convert from insured losses to total direct losses, one potential limitation. An increasing trend in annual aggregate losses is shown to be primarily attributable to a statistically significant increasing trend of about 5 % per year in the frequency of billion-dollar disasters. So the question arises of how such trend estimates are affected by uncertainties and biases in the billion-dollar disaster data. The net effect of all biases appears to be an underestimation of average loss. In particular, it is shown that the factor approach can result in a considerable underestimation of average loss of roughly 10–15 %. Because this bias is systematic, any trends in losses from tropical cyclones appear to be robust to variations in insurance participation rates. Any attribution of the marked increasing trends in crop losses is complicated by a major expansion of the federally subsidized crop insurance program, as a consequence encompassing more marginal land. Recommendations concerning how the current methodology can be improved to increase the quality of the billion-dollar disaster dataset include refining the factor approach to more realistically take into account spatial and temporal variations in insurance participation rates.     

基于GIS的空间数据和空间数据库浅谈

在数字城市、数字省区等数字工程建设和各个部门信息化建设迅速开展的时候，大量甚至海量空间数据的存储和管理成为地理信息系统建设工作者们面临的重要问题，研究空间数据和空间数据库变得非常迫切。简要介绍了空间数据的概念、特征和空间数据结构模型，并对空间数据库的设计做了简单阐述。     

基于空间数据和专家知识驱动的地质编图技术研究与应用

地质图编制专业性强、工作量大,编图环节繁琐,而人工智能、大数据等新一代信息技术的快速发展,为中国地质图的编图技术发展提供了支撑。在地质大数据环境下,提出基于地质知识驱动的地质编图技术,通过构建地质编图时空综合模型和地质代号智能识别模型,可以对多图幅的沉积岩、侵入岩、火山岩、变质岩、构造等地质要素进行人机交互式、自动化、智能化地图元综合、断层简化、线形圆滑、图幅接边等。近年来,基于该技术在青海东部地区、河南洛阳、郑州地区及京津冀多地区开展的编图实践表明,该编图技术能够显著提高地质编图工作效率,具有实际应用意义。     

基于OLE海量空间数据管理系统的设计

以泰宁基础地理信息系统的开发为例,探讨了基于OLE技术的海量空间数据管理系统的设计与数据库访问机制,提供了一种管理海量空间数据的方法。     

A comprehensive VIKOR method for integration of various exploratory data in mineral potential mapping

The central Iranian volcanic-sedimentary belt in Kerman province of Iran that is located within the Urumieh-Dokhtar magmatic arc zone is chosen to integrate diverse evidential layers for mineral potential mapping. The studied area has high potential of mineral occurrences especially porphyry copper, and the prepared potential maps aim to outline new prospect zones for further investigation. Two evidential layers including the downward continued map and the analytic signal of filtered magnetic data are generated to be used as geophysical plausible traces of porphyry copper occurrences. The low values of the resistivity layer acquired from airborne frequency domain electromagnetic data are also used as an electrical criterion in this study. Four remote sensing evidential layers including argillic, phyllic, propylitic, and hydroxyl alterations are extracted from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) images in order to map the altered areas associated with porphyry copper deposits. The Enhanced Thematic Mapper Plus (ETM+) images are used as well to prepare iron oxide layer. Since potassic alteration is generally the mainstay of copper ore mineralization, the airborne potassium radiometry data is used to explore both phyllic and potassic alteration. Finally, the geochemical layers of Cu/B/Pb/Zn elements and the main geochemical component responsible for ore mineralization extracted from principal component analysis are included in the integration process to prepare final potential maps. The conventional and the extended version of VIKOR method (as a well-known algorithm in multi-criteria decision making problems) produced two mineral potential maps, and the results were compared with the ones acquired from prevalent methods of the index overlay and fuzzy logic operators of sum and gamma. The final mineral potential maps based upon desired geo-data set indicate adequately matching of high potential zones with previous working and active mines of copper deposits.     

Robustness of statistical algorithms for location of microseismic sources based on surface array data

Here, we present a statistical simulation study of several array data processing techniques used for the location of sources of elastic waves. The source location problem arises in such engineering applications as radio-communications, acoustics, sonar, meteorology, astrophysics, seismology, etcetera. Recently, this problem has become important for applied geophysics in connection with the modern technology of hydrocarbon production based on the hydraulic fracturing of the surface layers of the Earth’s environment. These techniques are required for the monitoring of hydraulic fracturing through the location of sources of numerous microearthquakes that occur during cracking of crustal rocks. We have established theoretical connections among several location algorithms. In particular, two different theoretical interpretations were proposed for the phase alignment location algorithm, recently proposed for the seismic array data processing. The robustness properties of the phase alignment location algorithm and the adaptive maximum likelihood location algorithm were demonstrated through Monte Carlo simulation in regard to variations of those noise statistical features, which are typical under monitoring of microseismicity at the hydrocarbon production sites. In the framework of the Monte Carlo modeling, we also compared the two mentioned location algorithms with the so-called emission tomography algorithm that is developed for the location of microseismic sources during the monitoring of hydraulic fracturing.     

Shallow landslide hazard assessment using a physically based model and digital elevation data

 A model for the analysis of topographic influence on shallow landslide initiation is applied to an experimental mountain basin where high-resolution digital elevation data are available: the Cordon catchment (5 km²) located in northern Italy. The model delineates those areas most prone to shallow landsliding due to surface topographic effects on hydrologic response. The model is composed of two parts: a steady-state model for shallow sub-surface runoff and an infinite-slope Coulomb failure model which assumes that the soil is cohesionless at failure. An inventory of landslide scars is used to document sites of instability and to provide a test of model performance by comparing observed landslide locations with model predictions. The model reproduces the observed distribution of landslide locations in a consistent way, although spatial variations in soil strength and transmissivity, which are not accounted for in the model, influence specific distribution of landslide areas within regions of similar topographic control. Received: 15 October 1996 · Accepted: 25 June 1997