论地球空间信息科学的形成

从分析地球空间信息科学与全球变化监测和社会可持续发展的关系出发,回顾了地球空间信息科学产生的背景,提出地球空间信息科学的定义及内涵,概括了学科当前的发展状况,提出了现阶段学科研究的主要内容,最后,展望了地球空间信息科学的发展。     

基于HJ-1A高光谱影像的湿地精细分类

混合像元的存在不仅影响了基于高光谱影像的地物识别和分类精度,而且已成为遥感科学向定量化发展的主要障碍。本文以扎龙湿地为试验区,以环境一号卫星采集的高光谱影像为数据源,分别采用传统的全约束最小二乘光谱解混算法(fully constrained least squares spectral unmixing algorithm, FCLS)与基于稀疏约束最小二乘光谱解混算法(sparse constrained least squares spectral unmixing algorithm, SUFCLS)实现了试验区湿地的精细分类,并对两种分类结果的表现及其分类精度进行了对比分析。研究结果表明：SUFCLS算法能够自适应的从光谱库中选择场景中所占比例最高的一组端元,并将此端元的组合应用于传统的全约束最小二乘光谱解混中实现不同湿地类型丰度的提取,该算法充分考虑了端元的空间异质性,弥补了FCLS算法在端元选取过程中的不足。精度验证结果表明与FCLS算法相比,SUFCLS算法分类结果的均方根误差更小,丰度的相关系数更高,因此该方法对于提高湿地解混精度以及实现湿地精细化分类具有重要意义。     

基于KL-ISOMAP的高光谱图像彩色可视化

标志点等距映射（L-ISOMAP）作为一种降维方法,在高光谱图像可视化中极具潜力.针对L-ISOMAP算法标志点代表性不足以及计算代价较高的问题,提出了基于K-medoids聚类算法的改进型L-ISOMAP算法（KL-ISOMAP）,进而形成可视化方法.该可视化方法由以下几部分组成：1）通过改进型K-medoids算法选择标志点;2）根据相似度剔除相似像元;3）实现剩余像元的非线性降维;4）完成降维结果的可视化.实验结果表明,KL-ISOMAP算法一方面有效地提高了标志点的内在结构代表性,进而取得了更好的可视化效果;另一方面可通过对相似阈值的设置,加快算法的运算速度.由此形成的可视化方法有着较好的视觉效果、距离保持特性以及像元可分性.     

Value-added Impact of Geostationary Hyperspectral Infrared Sounders on Local Severe Storm Forecasts——via a Quick Regional OSSE

Accurate atmospheric temperature and moisture information with high temporal/spatial resolutions are two of the key parameters needed in regional numerical weather prediction(NWP) models to reliably predict high-impact weather events such as local severe storms(LSSs). High spectral resolution or hyperspectral infrared(HIR) sounders from geostationary orbit(GEO) provide an unprecedented source of near time-continuous, three-dimensional information on the dynamic and thermodynamic atmospheric fields—an important benefit for nowcasting and NWP-based forecasting. In order to demonstrate the value of GEO HIR sounder radiances on LSS forecasts, a quick regional OSSE(Observing System Simulation Experiment)framework has been developed, including high-resolution nature run generation, synthetic observation simulation and validation, and impact study on LSS forecasts. Results show that, on top of the existing LEO(low earth orbit) sounders, a GEO HIR sounder may provide value-added impact [a reduction of 3.56% in normalized root-mean-square difference(RMSD)] on LSS forecasts due to large spatial coverage and high temporal resolution, even though the data are assimilated every 6 h with a thinning of 60 km. Additionally, more frequent assimilations and smaller thinning distances allow more observations to be assimilated, and may further increase the positive impact from a GEO HIR sounder. On the other hand, with denser and more frequent observations assimilated, it becomes more difficult to handle the spatial error correlation in observations and gravity waves due to the limitations of current assimilation and forecast systems(such as a static background error covariance). The peak reduction of 4.6% in normalized RMSD is found when observations are assimilated every 3 h with a thinning distance of 30 km.     

空间功能视角下的公共服务对房价的影响——以成都市为例

房价的快速上涨和城市内部房价的巨大差异引起社会广泛关注,调控房价,防止局部区域房价过热势在必行。本文从城市空间功能的视角出发,以成都市2016年房价为例,基于地理探测器分析公共服务对房价的影响。结果表明：成都平均房价为8480元/m²,并从市中心沿交通环线和放射状干线同时向郊区递减,形成圈层加放射格局,总体上呈现西高东低、南高北低的特点。公共服务(主要包括医疗、金融和教育服务)对房价的影响以第三圈层和西南方最为显著,且高于城市层面上整体的影响。公共服务对房价的影响显著受不同区域的空间功能差异的影响,公共服务和空间功能差异会加剧房价的分异格局,并推动局部房价过热。因此,显著地受到在房价调控中,不仅要有传统的金融、经济政策,还要注重空间功能和公共服务的优化。     

嵌入式GIS系统实时响应的软件方法实现

嵌入式GIS的大量应用使得研究其实时性具有现实意义,选定嵌入式处理器等硬件平台后,可通过软件方法改善其实时性能。空间数据组织结构、多任务双缓存技术、地图符号绘制算法和合理数据调度等方法在本文中被详细阐述以提高实时性。测试结果表明,综合运用这些方法是有效的。     

An Integrated Mapping Approach to Petroleum Exploration on the Pratt Anticline,Pratt County,Kansas

A quantitative map comparison/integration technique to aid in petroleum exploration was applied to an area in south-central Kansas. The visual comparison and integration of maps has become increasingly difficult with the large number and different types of maps necessary to interpret the geology and assess the petroleum potential of an area; therefore, it is desirable to quantify these relationships. The algebraic algorithm used in this application is based on a point-by-point comparison of any number and type of spatial data represented in map form. Ten geological and geophysical maps were compared and integrated, utilizing data from 900 wells located in a nine-township area on the Pratt Anticline in Pratt County, Kansas. Five structure maps, including top of the Lansing Group (Pennsylvanian), Mississippian chert, Mississippian limestone, Viola Limestone (Ordovician), and Arbuckle Group (Cambro-Ordovician), two isopachous maps from top of Mississippian chert to Viola and Lansing to Arbuckle, a Mississippian chert porosity map, Bouguer gravity map, and an aeromagnetic map were processed and interpreted. Before processing, each map was standardized and assigned a relative degree of importance, depending on knowledge of the geology of the area. Once a combination of weights was obtained that most closely resembled the pattern of proved oil fields (target map), a favorability map was constructed based on a coincidence of similarity values and of geological properties of petroleum reservoirs. The resulting favorability maps for the study area indicate location of likely Mississippian chert and lower Paleozoic production.     

低通滤波器在高光谱影像分类中的应用

研究了低通滤波器对类别可分性的改善原理,指出将其应用于高光谱影像分类有利于获取更为准确的类别分布信息,进而提高影像分类精度。最后通过实验对低通滤波器在高光谱影像分类中的表现进行了验证。     

波浪在陡坡上的传播变形

利用数值方法和物理模型分析以反射为主的陡坡上波浪传播变形特性。数值方法采用标记单元法,为处理倾斜反射边界对斜坡前波浪运动的影响,提出了“台阶镜像法”。通过1：1．5光滑斜坡上物理模型试验,分析了不完全立波的运动特性,说明强反射光滑陡坡坡前波浪运动呈明显的立波状态,它与直墙反射的主要差别是被前第一波节点和腹点位置向岸推移。本试验得到的波浪反射、爬高和回落特征值与港口工程规范给定结果接近。     

莺歌海盆地拉张性质的研究

莺歌海盆地是南海北部陆架盆地的重要组成部分．本文根据ＭｃＫｅｎｚｉｅ（１９７８）的均匀拉张模型,并采用Ｍｉｄｄｉｅｔｏｎ（１９８４）在地震地史分析中的做法,由地震剖面资料得到进行去压实校正所需的地层资料．经过去压实校正和回剥处理,得出了盆地典型剖面的地层埋藏史和热沉降史．然后,由热沉降史通过与ＭｃＫｅｎｚｉｅ的理论曲线的对比,求出拉张因子分布．结果表明,莺歌海盆地为符合ＭｃＫｅｎｚｉｅ模型的盆地,南海的两次扩张在莺歌海盆地形成过程中有明显的反映．