构建信息化测绘保障体系的思考

结合工作实际,探讨了信息化测绘保障体系的基本内涵、主要特征,以及构建信息化测绘保障体系应强化的四种信息意识和应把握的四个重点问题,以供商榷。     

Wireless Mapping,GIS, and Learning about the Digital Divide: A Classroom Experience

Abstract

The purpose of this article is to describe a capstone course in undergraduate student geographical research in which GIS and other geospatial tools were used to teach undergraduate students basic geographical principles. The course uses the “cooperative learning” pedagogical approach to address one of a number of client-supplied research projects, chosen on the basis of logistical difficulty, time, student ability, and project importance. In the connection of primary data with existing data, students confronted a number of important research issues such as mapping ethics, database design and management, time management, group dynamics, and research limitations.     

基于GIS的小流域土壤侵蚀与产沙的简化模拟

将泥沙输移能力公式与USLE公式相结合,建立了一个简化的分布式小流域产沙模型,并将其应用于川中丘陵区小流域的土壤侵蚀与泥沙输移的空间分布模拟。得到的主要结论:1.该模型适用于川中丘陵区小流域产沙的模拟;2.魏城河流域1980—1987年8 a平均土壤侵蚀量为16.8×104t,侵蚀模数为675.8 t/(km2.a),模拟得到的输沙模数为238.6 t/(km2.a),泥沙输移比为0.35;3.魏城河流域主要以微度侵蚀为主,占到全流域总面积的68%,强度侵蚀占流域面积的1%,主要分布在坡度较陡的流域边缘地带;4.相对其他因子,降雨与坡度对该流域侵蚀产沙的影响更为突出。     

Microsimulation of large-scale evacuations utilizing metrorail transit

Public transit plays an important role in emergency evacuations, particularly for areas where public transit serves as a major commute mode for commuters. Microsimulation techniques provide great flexibility in assessing different scenarios in emergency situations. Combining GIS-based network analysis with microsimulation techniques, this study developed a framework to simulate emergency evacuations using rail transit. Applying the framework to a hypothetical attack on the Pentagon, this study investigated the performance of the Washington Metropolitan Area Transit Authority’s Metrorail for large-scale evacuations. A network-based analysis was performed to estimate the number of riders in association with each metro line and station. Using VISSIM, a multi-mode micro-simulation software package, this study integrated a pedestrian model with a Metrorail transit model to evaluate the performance of the Metrorail in the hypothetical evacuations. The simulation results suggested that if the potential of Metrorail transit is effectively utilized, it could be very useful resource during a large-scale evacuation. This study demonstrated the great potential and flexibility of microsimulation techniques for evaluating complex evacuation scenarios and strategies. The framework and approach used in this study can be applied to analyze other similar situations and help develop effective evacuation plans.     

Permafrost mapping of Northeast European Russia based on the period of climatic warming 1970-1995

Verdenskrigen som efterhånden i do krigførende land tok alle hjelpemidler og all intelligens i sin tjeneste og innskrenket den frie samferdsel selv for de nøitrale stater, måtte selvfølgelig legge hindringer i veien for forskningsekspedisjoner til Asia. De stoppet velikke helt op. Som vi skal se blev der også under krigen foretatt og begynt undersøkelser av denne art; men først efter krigen utviklet de sig igjen i større stil. Det synes derfor å være naturlig å velge denne verdenskatastrofe som et skille, og jeg vil i det følgende mere utførlig omtale bare de ekspedisjoner og forskninger, som vesentlig er blitt utført efter denne tid.     

Colour infrared aerial photography as a tool for vegetation mapping and change detection in environmental studies of Nordic ecosystems: A review

The aim of the paper is to sum up knowledge of colour infrared (CIR) aerial photography as a tool for vegetation data for mapping and monitoring in environmental and biodiversity surveys and change detection surveillance. It compiles thirty years of research of the main ecosystems in Swedish vegetation, where the overall goal was to develop methods for mapping and monitoring vegetation by use of CIR aerial photographs, assess the accuracy compared to field-based mapping and to implement them as a tool in nature conservation and environmental planning. The methods include development of a classification system, identification and analysis of indicators, development of interpretation techniques, and evaluation compared to the data collected in the field. The CIR observable criteria are colour, texture, pattern, size, form, and density, based on spectral reflectance, physiognomy, life forms, ecological conditions, moisture and nutrition, vegetation period and phenology, topography, site conditions, and management methods. The methods have been used to produce vegetation maps of mountains, boreal forests, and mires in northern and central Sweden, in national inventories of wetlands, ancient meadows and pastures, key biotopes in forests and for monitoring agricultural landscapes.     

非线性Schrödinger方程的一个线性化紧致差分格式

对非线性Schrödinger方程给出了一个线性化紧致差分格式,运用不动点定理和能量方法证明了格式的唯一可解性,还运用能量方法和数学归纳法,避开困难的先验估计,证明格式在空间方向和时间方向分别具有四阶和二阶精度,数值算例验证了格式的精度和数值稳定性.     

拉萨紫外辐射特征分析及估算公式的建立

本文利用2005~2010年的辐射观测资料对拉萨地区紫外辐射的时间变化特征及紫外辐射与总辐射比值的变化特征进行了分析,结果表明,紫外辐射与太阳总辐射的变化规律基本一致,日变化表现为正午大、早晚小;季变化特征是夏季6月最大,冬季1月最小.紫外辐射日累积值6年平均为0.87 MJ·m-2·d-1;紫外辐射有逐年递减的趋势.紫外辐射与总辐射比值也存在着明显日变化,表现为正午大、早晚小的规律;其季节变化也是夏季最大,冬季最小.紫外辐射与总辐射比值6年平均为0.0418;紫外辐射与总辐射比值也呈现逐年递减的趋势.利用2010年大气质量数和晴空指数,建立了适合于拉萨紫外辐射估量的公式,估算值的瞬时值与观测值的平均相对误差最大为8.66%,紫外辐射日累积重构值与观测值平均相对误差仅为5.5%.     

异常气温作用于水稻一维能量模型的数值分析

应用动力学方程建立四川内江市水稻的生长模型,通过FORCAL和MATLAB对方程参数拟合,并进行数值分析和定性分析,为水稻产量预报和气温对水稻生物量的影响评估提供科学依据。在传统的一维能量模型基础上,将水稻对外界能量的摄取能力与水稻生长季中的气温变化规律联系起来,得到水稻的生长曲线x（t）,并通过相平面轨迹得到x—T曲线,定性分析水稻的临界气温和最快生长率出现时间。通过低温对水稻分蘖期和高温对生殖生长期影响的比较,得出如下结论：水稻后期受高温影响比前期受低温影响严重。     

Hyperspectral remote sensing of evaporate minerals and associated sediments in Lake Magadi area, Kenya

Pleistocene to present evaporitic lacustrine sediments in Lake Magadi, East African Rift Valley, Kenya were studied and mapped using spectral remote sensing methods. This approach incorporated surface mineral mapping using space-borne hyperspectral Hyperion imagery together with laboratory analysis, including visible, near-infrared diffuse reflectance spectroscopy (VNIR) measurements and X-ray diffraction for selected rock and soil samples of the study area. The spectral signatures of Magadiite and Kenyaite, which have not been previously reported, were established and the spectral signatures of trona, chert series, volcanic tuff and the High Magadi bed were also analyzed.Image processing techniques, MNF (Minimum Noise Fraction) and MTMF (Mixture Tuned Matched Filtering) using a stratified approach (image analysis with and without the lake area), were used to enhance the mapping of evaporates. High Magadi beds, chert series and volcanic tuff were identified from the Hyperion image with an overall mapping accuracy of 84.3%. Even though, the spatial distribution of evaporites and sediments in Lake Magadi area change in response to climate variations, the mineralogy of this area has not been mapped recently. The results of this study shows the usefulness of the hypersspectral remote sensing to map the surface geology of this kind of environment and to locate promising sites for industrial open-pit trona mining in a qualitative and quantitative manner.