3S一体化技术支持下的西南地区冬小麦估产——以安宁河谷四县为例

农作物遥感估产已经是广泛应用的技术 ,但由于西南地区复杂的地貌类型以及遥感信息源等因素的限制 ,农作物估产方面的研究起步较晚 ,因而研究山区的农作物遥感估产对西南地区有重要的理论价值和现实意义。安宁河谷为一南北走向的山间盆地 ,是四川省第二大粮食生产基地。本文运用遥感 (RemoteSensing)、地理信息系统 (GIS)和全球定位系统(GPS)———简称 3S ,采取全数字式判读方式提取冬小麦的播种面积 ,进行野外点、线采样 ,并利用数理统计方法 ,建立了该地区的冬小麦估产模型     

基于AHP方法与GIS技术的海底管道路由选择研究

海底管道路由选择与海底管道建设、运营以及后期管理等工作存在密切联系,对管道工程经济性、安全性和合理性有着重要意义.考虑影响海底管道路由选择的自然与社会环境因素,构建了量化的评价体系,以AHP层次分析方法作为数学依据确定评价权重,建立了标准化的路由选择评判模型.进一步,将该模型与GIS空间分析技术相结合,生成以地图可视化...     

甘肃的寒武系

寒武系主要分布于北山、祁连山、河西走廊及陕甘宁盆地。根据沉积岩相及动物地理区系分为三大沉积区和７个沉积分区：北山沉积区分为下统双鹰山组、中统大豁落井组、上统西双鹰山组；祁连山沉积区未见下统，中统月牙山群、黑茨沟群和格尔莫沟群，上统香毛山群；华北沉积区下统未分，中统毛庄组、徐庄组和张夏组，上统仅见崮山组。三大沉积区的动物群分别为东南型（除早寒武世外）、过渡型和华北型。寒武系下界相当于滇东的沧浪铺阶之底界，并与震旦系冰碛层呈平行不整合接触。寒武纪岩相古地理轮廓受当时的地壳变动和气候条件所控制。早寒武世中晚期开始海侵，在北山沉积区之西部呈海湾，在陕甘宁盆地西缘呈浅海陆棚，省内其余地区（除西秦岭外）呈古陆状态。中寒武世广泛海侵，在祁连山形成海槽，且地壳运动加剧，火山喷发活动频繁。晚寒武世大规模海退，仅在北山局部地区、祁连山西段和陕甘宁盆地有沉积，其余均为古陆状态。     

Critical distances: Comparing measures of spatial accessibility in the riverine landscapes of Peruvian Amazonia

Quantitative measures of accessibility are increasingly used in land cover change modeling and in assessing human pressure on the environment. In riverine Amazonia the significance of physical accessibility for biodiversity, land use patterns and economic livelihoods is widely acknowledged, but attempts to quantify accessibility in practice have been few in number. In this study we compare different distance- and frequency-based measures of spatial accessibility and develop a quantitative model of accessibility patterns for the north-eastern Peruvian Amazonia where rivers form the core of the transportation network. We model accessibility between the rural areas of the Loreto region and the capital city of Iquitos, using different distance algorithms in a geographic information system, and complement the distance model with information on river boat frequencies and transport capacities. Patterns of accessibility are visualized in terms of potential production zones for different types of agricultural and non-timber forest products.This study demonstrates how results from different accessibility measures vary considerably. The mean Euclidean distance to Iquitos is almost 270 km, the mean network distance nearly 760 km and the mean travel time 70 h. Observed network distances from validation points to Iquitos are on average 1.6 times longer than Euclidean distances, and for the whole study area, the average ratio between modeled network distances and Euclidean distances is 3.1. The correlation between network distances and time distances is very strong, but time distances are relatively shorter along the major channels where boat traffic is considerably faster than along narrow, tightly meandering rivers. Measures of boat frequency and transport capacity show that availability of transport possibilities is highly varying across the region. These measures provide insights into the ’thickness’ of trade, indicating the level of market integration for riverine settlements. We conclude that quantifying accessibility in an environment like Peruvian Amazonia requires measures that take into account the spatial structure and dynamic nature of the riverine transportation network. Time as a unit of distance provides the most relevant measure of accessibility in the Amazonian context, where many human actions and traditional livelihoods are controlled by travel times between the regional core and the hinterland.     

Vulnerability of groundwater in Quaternary aquifers to organic contaminants: a case study in Wuhan City,China

More than 30 organic contaminants were detected in shallow groundwaters at Wuhan, the largest city in central China. Seriously contaminated groundwaters were from densely populated, industrial and commercial areas. Abnormal concentrations were found in groundwater from Hankou, downtown Wuhan: trimethylbenzene up to 29 μg/L, tetramethylbenzene up to 866 μg/L, and trichloroethene up to 9.5 μg/L. Benzene, Toluene, Ethylene and Xylene (BTEX) contamination of groundwater is serious and widespread at Wuhan, ranging between 0.14 and 25.0 μg/L. Considering the hydrogeological conditions of most Chinese cities, DRAMIC, a modified version of the widely used DRASTIC model, was proposed by the authors for assessing vulnerability of groundwater to contamination. The factors D, R, A and I in DRAMIC model are the same as in DRASTIC. The factor topography is ignored. The factor soil media is substituted by a new factor aquifer thickness (M) and the factor hydraulic conductivity of the aquifer by a new factor impact of contaminant (C). The equation for determining the DRAMIC Index is: DRAMIC = 5D _R + 3R _R + 4A _R + 2M _R + 5I _R + 1C _R. The calculated DRAMIC Index can be used to identify areas that are more likely to be susceptible to groundwater contamination relative to each other. The higher the DRAMIC Index is, the greater the groundwater pollution potential. Applying DRAMIC, a GIS-based vulnerability map for Wuhan city was prepared. Interestingly, places such as downtown Hankou, where enhanced concentrations of BTEX have been detected, correspond quite well with those with higher DRAMIC ratings.     

GIS与土壤溶质运移模型结合研究进展

地理信息系统对土壤溶质模型研究而言，使用者的要求与GIS所能提供的功能之间，还存在巨大的差距。出于对环境问题的关注，土壤中水分及溶质运移的规律及其对环境的影响，成为当前研究的热点。随着对土壤溶质运移模型研究的深入，一方面由于田间土壤特性具有很大的空间变异；另一方面，在实际应用中，往往溶质运移的宏观特征而非微观特征，具有更重要的意义。将溶质运移模型与GIS技术结合，定量研究空间尺度的溶质运移，成为溶质运移研究的必然发展趋势。由于计算机软硬件技术的发展，GIS正处于一个高速发展的时期。将GIS与溶质运移模型相结合，或者进一步，以GIS理论和技术为基础，建立基于GIS的溶质运移模型，将对溶质运移的规律及其对环境的影响，做出更深入和准确的描述。     

GIScience Journals Ranking and Evaluation: An International Delphi Study

Researchers’ fame in most scientific fields is closely linked to their publishing capacity, both in terms of quantity and quality. In GIScience, as in other fields, this situation demands that the researcher evaluate and to be very familiar with the scientific journals in which they could publish. Some specialized journals (e.g. Journal of Citation Reports or JCR) are devoted to ranking these reviews according to various methods and criteria. Compared to other scientific communities, GIScience is relatively new and constantly evolving. Therefore, the journals of this field do not benefit from any real formal ranking yet. The objective of this paper is to present the process and results of a study aimed at addressing this gap. More specifically, the challenge is to elaborate an importance ranking of the scientific journals in the field of GIScience. To do so, both a qualitative (Delphi study carried out with 40 international experts) and a quantitative (JCR impact factor) approach has been implemented. This triangulation method leads to an early global ranking of the journals of this field.     

基于GIS与ANN耦合技术的地裂缝灾情非线性模拟预测系统——以山西榆次地裂缝灾害为例

现代地裂缝在世界许多国家普遍存在 ,已成为当今世界范围内的主要地质灾害之一。本文在详尽分析了山西榆次地裂缝的各个致灾因子的基础上 ,利用GIS技术建立了地质学意义上的专题层 ;然后采用人工神经网络技术构建出了地裂缝灾害活动性的评价模型 ,并建立了地裂缝活动性的评价系统 ,对榆次地裂缝进行了灾害活动性评价 ,为榆次市城建和国土规划等部门的正确决策提供了重要的科学依据     

An approach to catchment‐scale groundwater nitrate risk assessment from diffuse agricultural sources: a case study in the Upper Bann,Northern Ireland

DRASTIC has drawbacks in groundwater risk assessment that are important in guiding activities to prevention agricultural diffuse groundwater pollution. This paper presents an improved and GIS‐based D‐DRASTIC approach for groundwater nitrate risk assessment from diffuse agricultural sources based on DRASTIC. D‐DRASTIC considers the risk concept, nitrate loading, pollutant transport with runoff, depth to water, net recharge, aquifer media, soil media, topography, impact of the vadose zone media, and the hydraulic conductivity of the aquifer. D‐DRASTIC was developed within an ArcGIS environment and applied to the Upper Bann Catchment, Northern Ireland as a case study. D‐DRASTIC shows that ‘very high’ and ‘high’ zones of groundwater nitrate risk occupy 5% and 11% of the case study area, respectively. When considering groundwater pollution sources and pathways, the results using D‐DRASTIC are helpful in guiding the activities of groundwater pollution prevention at the catchment scale in the context of better implementation of the EU Water Framework Directive. Copyright © 2008 John Wiley & Sons, Ltd.     

论地理科学体系建设

本文在论述重建地理科学体系必要性的基础上,提出和重点阐述一个新的地理科学体系的框架和内容,并由此分析我国未来地理科学学科建设的战略重点。