973 resultados para Gis


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借鉴国内外已有的太阳辐射计算方法,考虑地形和大气衰减因子,通过组件技术实现GIS与太阳总辐射计算模型集成,建立了太阳潜在总辐射计算模型。同时利用我国107个气象观测站的多年逐日太阳辐射资料,假设多年中有1d为晴朗无云的天气,即取多年中的最大太阳总辐射值为该计算日的潜在日总辐射值,进行模型检验,证明该方法可行

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应用地理信息系统和数据库等计算机技术,以东北地区DEM为基础,生成坡度、坡向及遮蔽度等小地形因子数据库和经度、纬度及海拔高度等大地形因子数据库。利用东北地区1960年~1990年30a平均的降水与湿度资料,采用趋势面分析、逐步回归、宏观地理因子模拟与小地形订正等方法,分区构筑了东北3省降水和湿度空间分布的数学模型。进而利用GIS平台建立分辨率为1km2的东北地区4月~10月份和全年降水与湿度的GRID格式专题地图,所得结果与东北地区实际降水和湿度分布较为吻合,可满足多方面的应用

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地理信息系统经过40多年的发展,形成了包括地理信息系统技术、地理信息科学和地理信息服务(科学)的综合体系,关注的重点已从技术软件系统转向信息服务。回顾历史可以知道:现代意义上的商业地理信息系统软件产品始于20世纪80年代初,也不过只有20多年的发展历史,然而发展速度之快,令人震惊。目前国际上的GIS软件厂商除了有ESRI、MapInfo等品牌GIS基础平台提供商之外,一些大型IT企业,如微软、Oracle、Google等也根据自己对行业的理解,或成立空间信息技术解决方案的部门,或通过并购等形式进入到

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应用遥感和GIS技术及数理统计学方法,以新疆三工河流域冲洪积扇-冲积平原型绿洲为研究区,利用1978年、1987年和1998年的遥感数据,深入研究了70年代中后期以来干旱区绿洲LUCC的过程和趋势。结果表明:(1)遥感和GIS在绿洲土地利用与覆被变化数据获取和空间分析方面是一种非常强大而有效的技术手段;(2)通过建立绿洲LUCC的幅度、速度、区域差异和变化趋势数学模型,可以较好的研究绿洲土地LUCC的过程和趋势,如变化的双向性、单向性、正向性和反向性,变化的涨势或落势等,在三工河流域绿洲应用取得良好效果;

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通过GIS技术的叠加和提取功能建立了焉耆盆地两个时间段的景观类型转移矩阵。在此基础上,分析了焉耆盆地内部绿洲景观类型的动态演化过程和空间分布特征。结果表明:焉耆盆地经过近40年的土地开垦后,人工绿洲呈现出上升的趋势,农田向自然绿洲和荒漠的扩张在整个研究阶段均可见;农田开垦的对象表现为从草地(含部分沼泽地)→多汁木本盐柴类荒漠→超旱生灌木半灌木荒漠迁移,体现了农田绿洲开垦从易到难,自然绿洲不断缩小,人工绿洲不断扩大的过程;对土地和水资源的不合理利用,导致盆地内湖泊水体、湖泊周边及农田绿洲出现明显的生态退化。

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本文简单介绍了地理信息系统的基本概念及GIS考古学的国内外研究状况,并结合国家自然科学基金项目“GIS支持的山东沭河上游聚落考古研究”课题和“基于GIS的黄河上游官亭盆地史前文化人地关系研究”课题所完成的工作,初步总结了地理信息系统在考古研究中的应用类型。

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以天山北坡三工河流域典型的人工绿洲景观为例,初步研究了干旱区绿洲景观斑块尺度绿洲稳定性,并借助遥感、GIS和数理统计方法,主要利用1978-1998年3期遥感影像数据,提出了景观斑块尺度绿洲稳定性的研究方法.结果表明:(1)绿洲斑块的景观控制力是景观动态变化的自然驱动力,控制力最强的斑块类型应为景观的基质;(2)绿洲景观斑块的转换是自然驱动力和人为驱动力共同作用的结果,但主要是人为干扰和驱动的结果,斑块转换的比例越高,则说明斑块类型的稳定性越低,也说明受人为干扰的程度越大;(3)1987年三工河流域控制力

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利用GIS描述海洋渔业资源时空动态变化,建立渔业资源评估模型和预测模型,是当前渔业现代化的重要趋势之一。在回顾海洋渔业地理信息系统(MFGIS)发展的基础上,分析了其应用实例及不足,重点探讨了MFGIS所面临的时空数据获取与标准、时空数据表达、时空动态尺度和时空统计与分析模型四方面的技术内涵,并讨论了解决途径。

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In addition to classical methods, namely kriging, Inverse Distance Weighting (IDW) and splines, which have been frequently used for interpolating the spatial patterns of soil properties, a relatively more accurate surface modelling technique is being developed in recent years, namely high accuracy surface modelling (HASM). It has been used in the numerical tests, DEM construction and the interpolation of climate and ecosystem changes. In this paper, HASM was applied to interpolate soil pH for assessing its feasibility of soil property interpolation in a red soil region of Jiangxi Province, China. Soil pH was measured on 150 samples of topsoil (0-20 cm) for the interpolation and comparing the performance of HASM, kriging. IDW and splines. The mean errors (MEs) of interpolations indicate little bias of interpolation for soil pH by the four techniques. HASM has less mean absolute error (MAE) and root mean square error (RMSE) than kriging, IDW and splines. HASM is still the most accurate one when we use the mean rank and the standard deviation of the ranks to avoid the outlier effects in assessing the prediction performance of the four methods. Therefore, HASM can be considered as an alternative and accurate method for interpolating soil properties. Further researches of HASM are needed to combine HASM with ancillary variables to improve the interpolation performance and develop a user-friendly algorithm that can be implemented in a GIS package. (C) 2009 Elsevier B.V. All rights reserved.

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Land-use change is an important aspect of global environment change. It is, in a sense, the direct result of human activities influencing our physical environment. Supported by the dynamic serving system of national resources, including both the environment database and GIS technology, this paper analyzed the land-use change in northeastern China in the past ten years (1990 - 2000). It divides northeastern China into five land-use zones based on the dynamic degree (DD) of land-use: woodland/grassland - arable land conversion zone, dry land - paddy field conversion zone, urban expansion zone, interlocked zone of farming and pasturing, and reclamation and abandoned zone. In the past ten years, land-use change of northeastern China can be generalized as follows: increase of cropland area was obvious, paddy field and dry land increased by 74. 9 and 276. 0 thousand ha respectively; urban area expanded rapidly, area of town and rural residence increased by 76. 8 thousand ha; area of forest and grassland decreased sharply with the amount of 1399. 0 and 1521. 3 thousand ha respectively; area of water body and unused land increased by 148. 4 and 513. 9 thousand ha respectively. Besides a comprehensive analysis of the spatial patterns of land use, this paper also discusses the driving forces in each land-use dynamic zones. The study shows that some key biophysical factors affect conspicuously the conversion of different land- use types. In this paper, the relationships between land- use conversion and DEM, accnmlated temperature(>= 10 degrees C) and precipitation were analysed and represented. We conclude that the land- use changes in northeast China resulted from the change of macro social and economic factors and local physical elements. Rapid population growth and management changes, in some sense, can explain the shaping of woodland/grassland - cropland conversion zone. The conversion from dry land to paddy field in the dry land - paddy field conversion zone, apart from the physical elements change promoting the expansion of paddy field, results from two reasons: one is that the implementation of market-economy in China has given farmers the right to decide what they plant and how they plant their crops, the other factor is originated partially from the change of dietary habit with the social and economic development. The conversion from paddy field to dry land is caused primarily by the shortfall of irrigation water, which in turn is caused by poor water allocation managed by local governments. The shaping of the reclamation and abandoned zone is partially due to the lack of environment protection consciousness among pioneer settlers. The reason for the conversion from grassland to cropland is the relatively higher profits of fanning than that of pasturing in the interlocked zone of farming and pasturing. In northeastern China, the rapid expansion of built-up areas results from two factors: the first is its small number of towns; the second comes from the huge potential for expansion of existing towns and cities. It is noticeable that urban expansion in the northeastern China is characterized by gentle topographic relief and low population density. Physiognomy, transportation and economy exert great influences on the urban expansion.

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Spatial relations, reflecting the complex association between geographical phenomena and environments, are very important in the solution of geographical issues. Different spatial relations can be expressed by indicators which are useful for the analysis of geographical issues. Urbanization, an important geographical issue, is considered in this paper. The spatial relationship indicators concerning urbanization are expressed with a decision table. Thereafter, the spatial relationship indicator rules are extracted based on the application of rough set theory. The extraction process of spatial relationship indicator rules is illustrated with data from the urban and rural areas of Shenzhen and Hong Kong, located in the Pearl River Delta. Land use vector data of 1995 and 2000 are used. The extracted spatial relationship indicator rules of 1995 are used to identify the urban and rural areas in Zhongshan, Zhuhai and Macao. The identification accuracy is approximately 96.3%. Similar procedures are used to extract the spatial relationship indicator rules of 2000 for the urban and rural areas in Zhongshan, Zhuhai and Macao. An identification accuracy of about 83.6% is obtained.

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Rapid urbanization and industrialization in southern Jiangsu Province have consumed a huge amount of arable land. Through comparative analysis of land cover maps derived from TM images in 1990, 2000 and 2006, we identified the trend of arable land loss. It is found that most arable land is lost to urbanization and rural settlements development. Urban settlements, rural settlements, and industrial park-mine-transport land increased, respectively, by 87 997 ha (174.65%), 81 041 ha (104.52%), and 12 692 ha (397.99%) from 1990 to 2006. Most of the source (e.g., change from) land covers are rice paddy fields and dryland. These two covers contributed to newly urbanized areas by 37.12% and 73.52% during 1990-2000, and 46.39% and 38.86% during 2000-2006. However, the loss of arable land is weakly correlated with ecological service value, per capita net income of farmers, but positively with grain yield for some counties. Most areas in the study site have a low arable land depletion rate and a high potential for sustainable development. More attention should be directed at those counties that have a high depletion rate but a low potential for sustainable development. Rural settlements should be controlled and rationalized through legislative measures to achieve harmonious development between urban and rural areas, and sustainable development for rural areas with a minimal impact on the ecoenvironment. (C) 2009 Elsevier Ltd. All rights reserved.

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黑白仰鼻猴(Rhinopithecus bieti)目前分布在金沙江和澜沧江之间横断山脉的一个狭小的区域范围内(26o14’N-29o20’N,99o15’E-99o37’E),海拔2 600 m(南部) - 4 200 m(北部)之间;目前大约有15 群,数量估计约1700 个体。是我国特有的灵长类之一,为国家Ⅰ级保护动物,在IUCN(世界自然保护联盟)2007 受威胁物种红皮书中被列为濒危物种并处于小种群、高度片断化状态(ENC 2a)。西藏是黑白仰鼻猴分布的北端,约有300 个体。基于前人的野外调查和报道确认,暗针叶林和针阔叶混交林是其适宜栖息地,人们在低海拔和高海拔砍伐或者火烧暗针叶林和针阔叶混交林的产物-农田和夏季牧场正在逐渐侵蚀着其适宜栖息地。尽管当地藏族村民信奉佛教,禁止猎杀任何野生动物,但是近些年来,黑白仰鼻猴栖息地不断丧失,这与牧场和农田扩张、当地人们薪柴采集等活动有关。黑白仰鼻猴西藏种群主要在原始暗针叶林和和针阔叶混交林里活动。为了评估该物种的栖息地现状和变化情况,我们通过野外调查工作,应用GIS 和RS 技术,分别解译了1986 年、1992 年、1997 年、2001 年和2006 年的Landsat TM/ETM+ 冬季卫星影像,并对解译结果进行了计算和分析,得到了以下西藏种群栖息地的主要结果: 1)现有暗针叶林(包括原始针叶林和针阔混交林)面积是30 500 hm2 ,夏季牧场面积是13 100 hm2 ,农田面积是6 400 hm2 ;2)在过去20 年间(1986-2006 年),暗针叶林面积减少了14.6%(5 200 hm2 ),夏季牧场面积增加了47.2%(4 200 hm2 ),农田面积增加了14.3%(800 hm2 );3)在过去20 年间,暗针叶林的斑块数量增加了68.4%,平均斑块面积下降了49.3%(从1986 年的15.1 hm2 下降到2006 年的7.6 hm2 ),最大的斑块指数下降了54.9%;景观丰富度并没有变化,但Shannon 多样性指数和Shannon 均匀度指数分别增加了2.7%。这都表明栖息地丧失和破碎化程度越来越严重。在上述结果的基础上,我们进一步对栖息地变化的主要原因进行了初步分析和探讨。通过暗针叶林面积、夏季牧场面积和农田面积和当地各乡村的家庭户数、人口数量、平均家庭人口数和牲畜存栏数等统计数据的Spearman秩相关分析表明,暗针叶林面积变化分别与当地的人口数量、家庭户数和平均家庭人口数呈显著负相关,与牲畜存栏数呈负相关;而夏季牧场面积和农田面积都分别与人口数量、家庭户数和平均家庭人口数呈显著正相关,与牲畜存栏数呈正相关。这意味着在目前当地传统生产方式基本未发生改变的情况下,因人口数量增加所带来的生产等活动强度的增加是黑白仰鼻猴栖息地丧失与破碎化加剧的主要原因(R2 = 0.972);当地人类经济活动的增加,如牧场和农田扩张,牲畜存栏数增加以及薪材采集和木质建筑等导致了栖息地丧失、退化和破碎化。但另一方面,当地一妻多夫的婚配制度(仅在西藏部分地区仍有保留)对黑白仰鼻猴的栖息地保护有积极的作用,因为大家庭(家庭人口数)的人均资源消耗,如薪柴需求、房屋数量、牧场和农田等,都比小家庭低。在过去20 年中(1983-2003 年),当地家庭户数的增加比人口数量增加要慢,这对黑白仰鼻猴的栖息地保护起到了一定的积极作用。因此,西藏种群作为单独的遗传亚种群,其保护工作任重而道远。