WebGIS空间数据结构研究   总被引：1，自引：0，他引：1  

李奇歆  张卫平  殷宁欣  王闯 《测绘与空间地理信息》2009,32(6):107-110

适宜的数据结构是网络地理信息系统各项功能完好运行的前提保证.文中简要介绍了一个基于网格式空间数据索引机制的矢量金字塔数据结构.该数据结构逻辑严谨,实用性强,运算效率较高,具有很强的可扩展性.我们利用该数据结构开发的网络地理信息系统平台已经在很多项目中得到应用.  相似文献   

A multilayer study of pCO2 in the surface waters of the Yellow and South China Seas in spring and the sea-air carbon dioxide flux     

Chunying Liu  Chuang Zhang  Xiaoman Yang  Haidong Gong  Zhengbin Zhang 《中国海洋大学学报(英文版)》2008,7(3):263-268

A multilayer study of pCO₂ for the Yellow and South China Seas in the surface waters was conducted based on data from four cruises sponsored by the China SOLAS Project in 2005 and 2006, including data for the surface microlayer (SML), subsurface layer (SSL) and surface layer (SL). The carbon fluxes across the air-sea interface were calculated. The results showed that the pCO₂ values in the surface waters of the study area decreased in the following order: pCO_{2 SML} > pCO_{2 SSL} > pCO_{2 SL}. The highest values were found in March for all SML, SSL and SL, followed by those in April, and the lowest were in May. The pCO₂ values had a significant positive correlation with temperature or salinity. While there was no relationship between pCO₂ and longitude, there was a significant negative correlation between it and latitude, i.e., ‘high latitude low pCO₂’. By using four calculation models, the carbon dioxide fluxes ( ) in spring in the Yellow and South China Seas, which were found to act as a ‘sink’ of atmospheric CO₂, were preliminarily estimated on the basis of the pCO₂ data in the SML to be −7.00×10⁶t C and −22.35×10⁶t C, respectively. It is suggested that the calculated on the basis of pCO₂ data in the SML is more reliable than that calculated on the basis of those in the SL.  相似文献   

基于“三调”数据的济南市永久基本农田划定和耕地保护研究          下载免费PDF全文

胡正超  齐俊  梁勇  吴闯  王长鹏  张雅芹 《山东国土资源》2022,38(10)

探索永久基本农田划定的有效路径，划定质优、集聚耕地为永久基本农田，有效配置耕地资源，对耕地保护和保障粮食安全具有重要意义。本文基于济南市“三调”成果，从多维度构建耕地综合质量和“可恢复”耕地潜力评价指标体系，根据评价结果将济南市耕地划分为优质、较优质、良好、一般、较差、不稳定与生态保护6种类型，将济南市“可恢复”耕地潜力划分为优先恢复区、适宜恢复区、不宜恢复区。客观反映了耕地综合质量和“可恢复”耕地潜力状况，得到济南市耕地和“可恢复”耕地的资源时空配置，为济南市及其他市县永久基本农田划定提供借鉴，为耕地资源差别化管控和耕地“进出平衡”方案编制实施提供参考。  相似文献   

阿克苏地区苹果始花期预报模型研究          下载免费PDF全文

刘海蓉  冯贝贝  张振军  梅闯  吴芳  闫鹏 《沙漠与绿洲气象(新疆气象)》2022,16(4):139-143

研究阿克苏地区苹果盛花期开放规律与温度之间的关系,为苹果花期之前相关农事的准备和预防不良天气对花期的影响提供参考依据。利用阿克苏地区2000-2019年苹果花期和气象数据,通过对苹果花期距平与3、4月的旬均温、≥0 ℃、3 ℃、5 ℃、10 ℃有效积温和活动积温的相关性分析,应用逐步回归方程,拟合出阿克苏地区苹果盛花期预报模型,对相关数据回代检测验证。研究表明：(1)与苹果树盛花期相关性大小依次为 3、4 月份有效积温>活动积温>逐旬平均气温；(2)花期距平与3月中旬均温为显著负相关,与其他指标具有极显著负相关性；(3)其中≥0℃的活动积温(X₁)和3月中旬平均温度(X₁₀)对阿克苏地区苹果盛花期影响较大,阿克苏地区苹果树花期预测模型Y= 39.882 - 0.075X₁+ 0.696X₁₀。模型拟合度较好,预测的盛花期实际值和拟合值相差绝对值为0-3d,满足生产需要。  相似文献   

两种大旋转角坐标转换方法的比较研究     

李庆港  韩闯  王磊 《测绘与空间地理信息》2022,45(4)

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Visualized liquefaction behavior of sandy soil deposited in water under undrained cyclic shearing     

Zhao  Chuang  Fauzi  Usama Juniansyah 《Acta Geotechnica》2022,17(8):3143-3160

Acta Geotechnica - Water films probably form beneath less-permeable interlayers in liquefiable deposits during an earthquake, further resulting in devastating disasters. However, the development of...  相似文献