城市土地定级中若干问题的探讨

结合实际工作,提出了体现主观和客观信息的综合赋权法,基于Voronoi图的土地定级因素影响半径确定方法,基于最短路径的因素影响距离计算方法和兼顾评价指标功能性和均衡性的城市土地定级评价模型.     

Spectral discrimination of giant reed (Arundo donax L.): A seasonal study in riparian areas

The giant reed (Arundo donax L.) is amongst the one hundred worst invasive alien species of the world, and it is responsible for biodiversity loss and failure of ecosystem functions in riparian habitats. In this work, field spectroradiometry was used to assess the spectral separability of the giant reed from the adjacent vegetation and from the common reed, a native similar species.The study was conducted at different phenological periods and also for the giant reed stands regenerated after mechanical cutting (giant reed_RAC). A hierarchical procedure using Kruskal–Wallis test followed by Classification and Regression Trees (CART) was used to select the minimum number of optimal bands that discriminate the giant reed from the adjacent vegetation. A new approach was used to identify sets of wavelengths – wavezones – that maximize the spectral separability beyond the minimum number of optimal bands. Jeffries Matusita and Bhattacharya distance were used to evaluate the spectral separability using the minimum optimal bands and in three simulated satellite images, namely Landsat, IKONOS and SPOT.Giant reed was spectrally separable from the adjacent vegetation, both at the vegetative and the senescent period, exception made to the common reed at the vegetative period. The red edge region was repeatedly selected, although the visible region was also important to separate the giant reed from the herbaceous vegetation and the mid infrared region to the discrimination from the woody vegetation. The highest separability was obtained for the giant reed_RAC stands, due to its highly homogeneous, dense and dark-green stands. Results are discussed by relating the phenological, morphological and structural features of the giant reed stands and the adjacent vegetation with their optical traits. Weaknesses and strengths of the giant reed spectral discrimination are highlighted and implications of imagery selection for mapping purposes are argued based on present results.     

水稻生长期微波介电特性研究

利用植被介电常数的Debye-Cole双频色散模型，模拟计算了广东肇庆水稻试验区1996年晚稻和1997年早稻人插秧期、发蘖期、扬花期到成熟期各生长期的介电常数值，并根据计算结果，探讨了电磁波频率、水稻含水量、温度、含盐度及水稻冠层干体密度对介电常数的影响。其中，不同生长期水稻的介电常数各不相同，不同水稻类型（早稻和晚稻），介电常数的变化趋势不尽相同。电磁波频率、水稻含水量、温度和水稻冠层干体密度均对介电常数有不同程度的影响，而含盐度却对介电常数影响不大。     

先秦测绘史考

介绍先秦时期，包括三皇五帝传说时期，以及夏、商、西周、春秋，占国时代的测绘历史，并对先秦的时间上限选择，测绘史迹从神化到人化的演化，测绘学由潜科学到显科学的转变等问题进行了论述。     

基于雷达干涉永久散射体网络探测地表形变的算法与实验结果

为削弱常规卫星DInSAR技术在区域地表形变探测应用中时空失相关与大气延迟的负面影响,探索和发展了基于永久散射体(PS)观测网络建模与参数稳健估计的算法并开发一套完整的计算程序,可达到分离和提取线性与非线性形变时间序列、地形数据误差与大气信号的目的。以上海市沉降场为对象,选取1992~2002年间ERS-1/2卫星所获取的26幅SAR影像为源数据,分别开展模拟和真实数据的实验,证实该算法和计算程序是有效而可靠的。     

An algorithm for automatic cartographic sounding selection

Soundings on nautical charts provide information about the shape of ocean bottom between chart depth curves. A single chart may have thousands of soundings posted on it. This paper describes a new algorithm for selecting soundings automatically. At first, the problem encountered in automatic cartographic sounding selection is presented. Then the authors give the principle of the new algorithm, and the implementation is illuminated in detail. At last the experiments prove the rationality and efficiency of the new algorithm.     

Constrained edge dynamic deleting in CD-TIN based on influence domain retriangulation of virtual point

Constrained Delaunay triangulated irregular network is one kind of dynamic data structures used in geosciences. The research on point and edges insertion in CD-TIN is the basis of its application. Comparing with the algorithms of points and constrained edge insertion, there are very a few researches on constrained edge deletion in CD-TIN. Based on the analysis of the polymorphism of constrained edge, virtual points are used to describe the intersection of constrained edges. A new algorithm is presented, called as influence domain retriangulating for virtual point (IDRVP), to delete constrained edges with virtual points. The algorithm is complete in topology. Finally, the algorithm is tested by some applications cases.     

起算数据误差对平差值及其精度的影响

讨论了起算数据误差对平差值和平差值精度的影响,给出了计算各种影响值的公式和应用实例,并对实例计算结果进行了分析和讨论。     

城市举办大型活动的气候适宜期及其确定方法

根据河南城市大型商贸文体活动日益增多的实际需要,按不同活动对气候条件的要求,提出用单项排除和综合舒适指数两种方法来确定气候适宜期,并构建了多要素综合舒适指数的计算方法。在此基础上,以郑州为例,用以上两种方法确定了郑州举办大型社会活动的适宜的季节和日期,为决策机构提供了一项基本的气候依据。     

淹水条件下鄱阳湖3种湿地植物腐烂分解及其对水质的影响

大型通江湖泊水位不断变化,引起湖泊水域与洲滩湿地之间相互转化,造成湿地植物周期性淹没分解,影响水体营养物质循环和能量流动.本文以鄱阳湖典型湿地植物灰化薹草(Carex cinerascens)、蒌蒿(Artemisia selengensis和虉草(Phalaris arundinacea)为研究对象,通过为期69 d...