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Gridding cropland data reconstruction over the agricultural region of China in 1820

Recent studies have demonstrated the importance of LUCC change with climate and ecosystem simulation, but the result could only be determined precisely if a high-resolution underlying land cover map is used. While the efforts based satellites have provided a good baseline for present land cover, what the next advancement in the research about LUCC change required is the development of reconstruction of historical LUCC change, especially spatially-explicit historical dataset. Being different from other similar studies, this study is based on the analysis of historical land use patterns in the traditional cultivated region of China. Taking no account of the less important factors, altitude, slope and population patterns are selected as the major drivers of reclamation in ancient China, and used to design the HCGM (Historical Cropland Gridding Model, at a 60 km×60 km resolution), which is an empirical model for allocating the historical cropland inventory data spatially to grid cells in each political unit. Then we use this model to reconstruct cropland distribution of the study area in 1820, and verify the result by prefectural cropland data of 1820, which is from the historical documents. The statistical analyzing result shows that the model can simulate the patterns of the cropland distribution in the historical period in the traditional cultivated region efficiently.     

数据网格化的局部搜索算法

作者在本文中提出一种数据网格化的快速算法－局部搜索算法。该算法利用目前计算机编程环境提供了动态存储分配功能,首先将需网格化的所有数据划分至各个子块中,网格化时在一个或几个子块中搜索网格点的相邻点,而不是对所有数据进行探索,提高了数据网格化的搜索效率,对于数据量较大的网格化问题可极大地提高效率。经实际应用证明,该方法稳定、可靠,是一种值得推广应用的快速算法。     

A simple data transformation technique for pre-processing survey data at embayed beaches

This note explains a technique used for pre-processing three-dimensional survey data obtained at embayed beaches that exhibit distinct alongshore curvature. Using a log-spiral function fitted to the beach planform, the data is transformed from Cartesian into an alternative alongshore–cross-shore coordinate system. When undergoing this transformation, the curvature in the survey data is effectively removed. This greatly simplifies the application of standard interpolation methods, and in this transformed coordinate system the alongshore and cross-shore directions are now explicitly defined. Using a property unique to the log-spiral, the interpolated data is readily transformed back into the original Cartesian coordinate system for further analyses and interpretation. The practical application and advantages of this technique are then demonstrated using survey data from two embayed beaches in south-eastern Australia.     

富钴结壳资源远景区圈定方法

提出了4种不同的富钴结壳资源远景区圈定方法,即水深法、工程间距外推法、网格微分法和综合法,对比了它们的优缺点,对同一研究区运用不同的方法圈定了不同的资源远景区并进行了资源评价,结果表明:这几种方法是层层递进、相辅相成的,水深法和工程间距外推法可以给出研究区资源远景的大致范围,网格微分法是圈定较为精确资源远景区的基础,但是,加入地质规律的综合法可以提供更接近真实情况的资源远景区。不同的方法适合不同的勘探程度和不同研究目的,并且有不同的精度。     

格形地连墙与软土相互作用的离心试验研究

格形地下连续墙（GCRW）是一种常用于软土地区的基坑开挖的新型支护结构,该结构与软土的相互作用是必须深入研究的关键问题。结合背景工程,首先进行了格形地连墙模型的设计和试验方案的制定,通过离心模型试验模拟了分步开挖基坑时格形地连墙和软土的相互作用,并把测定结果与朗肯土压力进行了比较。试验结果表明,土压力基本上呈现线性变化特征,格形地连墙因基坑开挖引起的前墙内侧土压力而产生变形和位移;格形地连墙和格子内的土体作为一个整体在土压力的作用下保持平衡,受力特征与重力式支护结构相似。支护结构处于最不利状态时,主动区土压力介于朗肯静止土压力和主动土压力之间,而被动区土压力大于朗肯被动土压力,前墙没有倾覆是因为受到了隔墙拉力     

基于C#的三维电离层模型投影矩阵的计算

叙述了格网电离层模型的建立原理和数学模型,重点探讨了确定三维电离层模型投影矩阵的计算方法和过程.借用某一区域CORS站的数据,利用C#语言实现了三维电离层模型投影矩阵.     

基于MODIS数据网格化重建历史耕地空间分布的方法——以清代云南省为例

建立具有准确空间属性的历史时期土地覆被数据集有助于更好地模拟土地覆被变化的过程及其效应。本文基于我国过去300年耕地面积总体呈持续增加的特点,提出了历史时期耕地分布范围未超出现代耕地范围的合理假设,并以地表高程和坡度为影响土地宜垦程度的主导因子,评估了MODIS土地覆被产品中现代耕地分布区域的宜垦程度,再按宜垦程度从高...     

卫星参考站用户频数与当地经济的相关性分析

针对现有经济地理国情监测时效性较差、方法较为单薄等不足,该文提出一种利用卫星参考站用户频数与当地GDP的相关性进行分析的思路:利用2012年至2013年上半年的江苏省CORS服务数据,结合2012年人均GDP,综合分析得出两者相关性高达0.94,并结合地统计学处理方法做格网化处理,分析江苏省当年经济建设的现状和热点。实验结果表明,该方法能快速获取江苏省经济热点分布的相关信息,相关性参数可以作为江苏省经济地理国情动态监测的一个敏感相关量观测值,供系统分析者参考。     

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