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1978-2012年武陵山区公路通达性演化及其对经济发展的影响 总被引：1，自引：0，他引：1
利用通达性系数和加权平均出行时间,结合GIS网络分析和空间分析方法,探讨了1978-2012年武陵山区64个县（市、区）与武陵山区及其外围38个地级市以上城市之间通达性演化的格局和特征,并分析了2000-2012年武陵山区经济发展格局,采用柯布—道格拉斯生产函数模型,定量模拟了通达性对经济发展的影响。研究发现：1978-2000年,武陵山区通达性系数的稳定性较好,到2012年,通达性系数较小值具有向武陵山区东南部集聚的趋势。1978-2000年武陵山区的经济加权平均出行时间和人口加权出行时间的优劣程度均具有由东向西逐渐下降的“圈层式”布局的特点,到2012年,经济加权平均出行时间和人口加权平均出行时间较小值均具有向武陵山区东南部迁移的趋势,原因在于武陵山区及其外围的东部和南部城市较多且路网发展更为迅速和完善。2000-2012年,武陵山区经济发展格局相对稳定,形成了“东部和西北部强、西南部和中北部弱”的经济发展格局,但经济发展的绝对差距逐步扩大,两极分化的趋势越来越明显。2000-2012年武陵山区通达性的重要程度发生变化,通达性的优劣程度对于GDP的影响明显上升,通达性的改善在整体上较好地促进了武陵山区GDP的增长,对武陵山区经济发展的作用变得越来越重要。同时,通达性改善削弱了第一产业的发展,但对第二产业发展具有逐渐上升的正向影响,对第三产业发展的正向影响显著上升。研究充实了贫困地区交通与经济发展关系的实证和理论,对武陵山区通达性改善与经济发展具有重要的指导意义,可以为相关政策的制定提供参考依据。 相似文献
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空间互操作框架集成模式分析 总被引：3，自引：1，他引：2
空间互操作已经成为地理信息共享领域研究的重要内容,广义的空间互操作也逐渐成为空间共享技术的代名词。虽着空间互操作研究的深入,空间互操作的模式与方法也逐步多样化起来。本文分别对基于语义空间数据互操作模式,开放式地理数据互操作规范与分布式异构数据库互操作框架,主流GIS平台互操作产品以及ISO/TC211的空间互操作服务体系结构进行分析的基础上,提出了改善各种互操作技术,以提升互操作性能的方法,指出了空间互操作技术框架的发展规律与趋势。从数据转换到开放文件格式,从标准交换格式到应用程序接口,从空间数据库到Web服务的集成,随着时间和互操作技术的发展,互操作的性能也在逐步提升。 相似文献
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Surface modeling with very large data sets is challenging. An efficient method for modeling massive data sets using the high accuracy surface modeling method (HASM) is proposed, and HASM_Big is developed to handle very large data sets. A large data set is defined here as a large spatial domain with high resolution leading to a linear equation with matrix dimensions of hundreds of thousands. An augmented system approach is employed to solve the equality-constrained least squares problem (LSE) produced in HASM_Big, and a block row action method is applied to solve the corresponding very large matrix equations. A matrix partitioning method is used to avoid information redundancy among each block and thereby accelerate the model. Experiments including numerical tests and real-world applications are used to compare the performances of HASM_Big with its previous version, HASM. Results show that the memory storage and computing speed of HASM_Big are better than those of HASM. It is found that the computational cost of HASM_Big is linearly scalable, even with massive data sets. In conclusion, HASM_Big provides a powerful tool for surface modeling, especially when there are millions or more computing grid cells. 相似文献
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Yue Tianxiang Zhao Na Liu Yu Wang Yifu Zhang Bin Du Zhengping Fan Zemeng Shi Wenjiao Chen Chuanfa Zhao Mingwei Song Dunjiang Wang Shihai Song Yinjun Yan Changqing Li Qiquan Sun Xiaofang Zhang Lili Tian Yongzhong Wang Wei Wang Ying’an Ma Shengnan Huang Hongsheng Lu Yimin Wang Qing Wang Chenliang Wang Yuzhu Lu Ming Zhou Wei Liu Yi Yin Xiaozhe Wang Zong Bao Zhengyi Zhao Miaomiao Zhao Yapeng Jiao Yimeng Naseer Ufra Fan Bin Li Saibo Yang Yang Wilson John P. 《中国科学:地球科学(英文版)》2020,63(8):1092-1112
We propose a fundamental theorem for eco-environmental surface modelling(FTEEM) in order to apply it into the fields of ecology and environmental science more easily after the fundamental theorem for Earth's surface system modeling(FTESM). The Beijing-Tianjin-Hebei(BTH) region is taken as a case area to conduct empirical studies of algorithms for spatial upscaling, spatial downscaling, spatial interpolation, data fusion and model-data assimilation, which are based on high accuracy surface modelling(HASM), corresponding with corollaries of FTEEM. The case studies demonstrate how eco-environmental surface modelling is substantially improved when both extrinsic and intrinsic information are used along with an appropriate method of HASM. Compared with classic algorithms, the HASM-based algorithm for spatial upscaling reduced the root-meansquare error of the BTH elevation surface by 9 m. The HASM-based algorithm for spatial downscaling reduced the relative error of future scenarios of annual mean temperature by 16%. The HASM-based algorithm for spatial interpolation reduced the relative error of change trend of annual mean precipitation by 0.2%. The HASM-based algorithm for data fusion reduced the relative error of change trend of annual mean temperature by 70%. The HASM-based algorithm for model-data assimilation reduced the relative error of carbon stocks by 40%. We propose five theoretical challenges and three application problems of HASM that need to be addressed to improve FTEEM. 相似文献
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粒度和磁化率记录的毛乌素沙地东缘全新世气候变化 总被引：3，自引：2，他引：1
通过对毛乌素沙地东缘大柳塔剖面地层沉积物粒度及磁化率特征的分析,结合光释光测年结果,探讨了毛乌素沙地全新世气候变化。结果表明:(1)剖面沉积物粒度组成以中砂、粗砂为主,古土壤中黏粒组分含量高(3.32%),风成砂中几乎不含黏粒组分(0.01%),粒度参数的平均粒径M_z和分选系数σ也表现为古土壤高值、风成砂低值;(2)磁化率在全剖面呈有规律的变化,低频、高频磁化率在古土壤中呈高值,湖沼相、弱成壤次之,风成砂最小;低频磁化率χlf与黏粒(<2μm)含量、平均粒径M_z呈显著正相关,垂向剖面上变化规律一致,指示了相似的气候环境意义;(3)毛乌素沙地在10.39 ka BP附近存在明显的3次冷干-暖湿气候波动; 10.39～9.34 ka BP,气候冷干,风沙活动盛行; 9.34～8.68 ka BP,冬季风衰退,夏季风增强,成壤作用强烈; 8.68～8.29 ka BP,气候寒冷干燥; 8.29～2.72 ka BP,气候整体温暖湿润,在6.55～3.80 ka BP达到鼎盛后转向冷干; 2.72～1.34 ka BP,冬季风占主导,沙丘活化,沙漠扩张; 1.34 ka BP至今,逐渐接近现代气候。毛乌素沙地的全新世气候变化是东亚冬、夏季风此消彼长作用下全球气候变化的区域响应。 相似文献
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基于地理对象的影像分析方法已成为高分辨率遥感影像分析的重要手段。影像分割作为其关键步骤,如何设置合适的分割算法参数对后续分割和分类结果有重要的影响。目前分割参数优选方法的探讨分别从非监督与监督分割质量评价2个方面展开,而何者更适合高分辨率遥感影像特定目标地物分析仍缺乏对比研究。本文以城镇和乡村为例,选取多源遥感数据Quickbird、WorldView-2和ALOS影像中共有的3种典型土地覆被为研究对象,基于2种具有代表性的非监督与监督方法ESP2 (Estimation of Scale Parameter 2)与ED2 (Euclidean distance 2) 进行实验,对最优分割和分类的结果进行全面的对比分析。结果表明：① 相同实验参数下,监督方法均能以较少的分割数据集获得目标地物的最优分割结果,且与真实地理对象吻合度更高;② 非监督方法依靠影像自身特征分析进行分割参数优选,无法克服不同景观格局和影像分辨率的影响,而监督方法可通过改变参考数据集的面积和空间分布模式等来降低其影响;③ 非监督方法往往因为欠分割而漏分小目标地物,这样会严重影响局部分类结果。虽然本文中非监督与监督方法的整体分类精度均可达90.08%以上,但非监督方法的漏分率却是监督方法的1.43~4.65倍。因此,本研究认为监督方法更适合分析高分辨率遥感影像特定小目标地物。 相似文献
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WANG Shaoqiang WANG Junbang ZHANG Leiming XIAO Zhishu WANG Feng SUN Nan LI Daiqing CHEN Bin CHEN Jinghua LI Yue WANG Xiaobo WANG Miaomiao 《资源与生态学报(英文版)》2019,10(2):105-111
Ecological quality is defined as the stability, adaptability and resilience of an ecosystem. Monitoring and assessing ecological quality are important bases for China's ecological civilization construction. The national key research and development program “Technologies and guidelines for monitoring ecological quality of terrestrial ecosystems in China”, launched in July 2017, includes plans to study the observation technologies and provide guidelines on the ecological in-situ observation, the regional biodiversity and ecosystem function monitoring and its applications, all of which contribute to national ecological quality assessment. A year after its implementation, some important progress has been achieved, such as building the indicator system for comprehensive monitoring of ecological quality and improvement of the methods, mass data transmission, infrared camera-based monitoring of biodiversity, multi-angle automatic spectral observation systems, and unmanned aerial vehicle (UAV) based desert monitoring. We have organized this special issue and attempted to introduce the monitoring techniques and assessment methods on ecological quality from different perspectives in order to further promote the development of ecology and its observation methods. 相似文献
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全球气候变化及快速城市化增加了极端天气事件的发生频率,高温热浪作为其中的典型效应,增加了与热相关的健康风险,越来越受到气象学、医学与地理学学者的关注。论文系统梳理了高温热浪的定义,从地理学视角,以空间评估作为切入点,总结分析了高温热浪脆弱性评估中的空间指标、空间制图方法与空间对策等方面的研究进展,指明该领域已从单一视角逐步深入到气象学、医学、地理学等复合学科的交叉研究,地理学作为桥梁将气象学与医学有机结合,为脆弱性评估提供空间指标参数、为制图提供思路与方法,并提供空间对策连接规划和风险预警等实践工作。未来的研究展望包括：空间指标综合各学科研究需要、集成各学科优势进行构建,空间制图在社区小尺度到区域大尺度的耦合机理分析基础上探讨跨区域研究表达方式,空间对策针对不同风险人群采取差异化研究,为城市适应气候变化提供科学依据。 相似文献