基于形态学及傅里叶分析对两种南极冰鱼耳石外型的研究

根据2014年3—4月以及2015年4—9月在南设得兰群岛以及南乔治亚群岛周边水域采集的裘氏鳄头冰鱼(Champsocephalus gunnari)及雪冰(Chionobathyscus dewitti)样本,对其耳石进行5种基础形态参数测量并转换为7种形态学参数,比较分析了两种冰鱼间的耳石形态学差异,再利用傅里叶分析法选取两种耳石的77个傅里叶系数进行判别。结果表明,两种冰鱼耳石长、高、周长、面积及质量均与体长呈显著的幂指数关系(P0.01)。由形态指标分析可知,裘氏鳄头冰鱼较雪冰耳石环率更低,即更趋近于圆,更为规则,且耳石厚度上略薄。两者各项形态参数间均存在显著性差异(P0.01)。对耳石77个傅里叶谐值进行主成分分析,其中前20个主成分解释总变异的82.491%,两种冰鱼的因子分布图上重叠量较少,可见区分度较好,判别分析选取了其中的6个傅里叶值建立了判别函数,总体判别率为96.15%。总体而言,可利用耳石外型对两种冰鱼进行种类判别,傅里叶分析更为直观清晰且较为准确。本研究可为南极冰鱼耳石形态学研究提供基础数据,并就其种类鉴别提供备选方法。     

A trajectory clustering approach based on decision graph and data field for detecting hotspots

Spatial clustering can be used to discover hotspots in trajectory data. A trajectory clustering approach based on decision graph and data field is proposed as an effective method to select parameters for clustering, to determine the number of clusters, and to identify cluster centers. Synthetic data and real-world taxi trajectory data are utilized to demonstrate the effectiveness of the proposed approach. Results show that the proposed method can automatically determine the parameters for clustering as well as perform efficiently in trajectory clustering. Hotspots are identified and visualized during different times of a single day and at the same times on different days. The dynamic patterns of hotspots can be used to identify crowded areas and events, which are crucial for urban transportation planning and management.     

A building label placement method for 3D visualizations based on candidate label evaluation and selection

Adding building labels greatly improves the recognizability of buildings and the readability of three-dimensional (3D) city scenes. However, building label placement is much more complex in 3D scenes than in two-dimensional (2D) maps. The annotation effect is influenced by the attributes of the 3D label, building visibility, and the spatial relationship between the building and viewpoint. In this context, automatically generating building labels for 3D scenes during interactions requires highly complex computations. By contrast, evaluating candidate labels and then selecting the suitable label for each building can be effectively implemented. This paper introduces an approach for labeling buildings in 3D scenes based on evaluations of label candidates. The proposed method predefines a candidate label set for each building. These candidates are then evaluated in terms of their attributes and the relationship between the labels and viewpoint at runtime. The best candidate label, or a situational alternative for each building, is then placed in order of comprehensive label priority to avoid annotation conflicts. A series of experiments demonstrate that this method effectively enhances the correlation of labels and buildings, improves interactive efficiency, and realizes a viable global label layout.     

黄河流域绿色发展效率时空演进

识别黄河流域绿色发展效率及其时空演进规律,有助于区域产业布局、环境规制与政策制定,进而实现黄河流域生态保护和高质量发展。针对黄河流域异质化发展,结合经济发展和环境治理的区域发展规律,构建多周期两阶段DEA模型（Multi-period two-stage DEA model）,通过测算绿色经济效率与绿色创新效率,实现黄河流域省市的绿色发展效率测度,同时借助ArcGIS10.6软件对黄河流域省域绿色发展的时空格局进行了动态演进并分析其发展路径。结果表明：黄河流域空间维度呈现上游较差、中游一般、下游最优的发展不均衡现状;时间维度呈现“W”型波动式上升趋势,但整体一般;存在省份绿色发展水平较高、黄河段城市却较差的发展不一致现象。针对黄河流域省市的各种发展情境,从省市协同治理、政府引导、产业结构、科技研发、税收政策等方面提出了建议。     

Refined technique for susceptibility resolution into ferromagnetic and paramagnetic components based on susceptibility temperature-variation measurement

The measurement of the temperature variation of magnetic susceptibility can be used for the separation of ferromagnetic and paramagnetic susceptibility components. The method suggested by Hrouda (1994) assumes a hyperbolic dependence of paramagnetic, susceptibility and constant ferromagnetic susceptibility in the temperature interval used for the separation. Our new method works with a paramagnetic hyperbola again, but assumes that the ferromagnetic susceptibility temperature variation is represented by a linear relationship in the resolution interval, as indicated by the investigation of monomineralic ferromagnetic fractions.     

基于因素分解模型的辽宁省用水变化驱动力测度及时空分异

通过构建用水变化的因素分解模型,测度了1994-2006年辽宁省用水变化驱动力的经济增长效应、产业结构效应、用水强度效应及混合效应,并对各种效应进行了时间分异分析;测度了1994-2006年辽宁省14个地级市用水变化驱动力的四种效应,对各种效应进行空间聚类,进而对各种效应进行空间分异分析。结果表明:(1)经济增长拉动了水资源利用量的增长,1994-2006年平均效应为15.92×108m3/a;而用水强度和产业结构和混合效应的变化对水资源利用量的扩张起到了一定的遏制作用,同时期年平均效应分别为-12.44×108m3/a、-1.38×108m3/a和-1.88×108m3/a;(2)在1994-2006年间,经济增长效应的平均贡献率约为42.48%,用水强度效应的平均贡献率约为31.24%,产业结构效应的平均贡献率约为12.34%,混合效应的平均贡献率为4.72%。经济增长与用水强度变化是辽宁省用水变化的决定因素;(3)经济增长效应的波动性最小,对水资源利用量变化趋势起到稳定作用,产业结构效应的波动性最大,对水资源利用量变化趋势起到冲击作用,而用水强度效应和混合效应的波动性居于二者之间,是改变水资源利用量变化...     

MODIS雪深反演数学模型验证及分析

在MODIS卫星遥感积雪监测的基础上,利用雪深反演数学模型、积雪指数NDSI和多光谱阈值等相结合的方法,对2004年以来新疆北疆地区的积雪分布状况进行了反演和计算,并利用2004年11月～2005年3月冬季北疆地区气象台站雪深数据和2004年12月～2006年1月加密野外实测雪深数据,对反演雪深数据进行了验证及分析,北疆各地除塔城地区反演精度为83.2%以外,其它地区反演精度达85.2%以上,平均反演精度达86.2%;野外实测数据验证反演精度达92%以上。     

A high-performance cellular automata model for urban simulation based on vectorization and parallel computing technology

Cellular automata (CA) models can simulate complex urban systems through simple rules and have become important tools for studying the spatio-temporal evolution of urban land use. However, the multiple and large-volume data layers, massive geospatial processing and complicated algorithms for automatic calibration in the urban CA models require a high level of computational capability. Unfortunately, the limited performance of sequential computation on a single computing unit (i.e. a central processing unit (CPU) or a graphics processing unit (GPU)) and the high cost of parallel design and programming make it difficult to establish a high-performance urban CA model. As a result of its powerful computational ability and scalability, the vectorization paradigm is becoming increasingly important and has received wide attention with regard to this kind of computational problem. This paper presents a high-performance CA model using vectorization and parallel computing technology for the computation-intensive and data-intensive geospatial processing in urban simulation. To transfer the original algorithm to a vectorized algorithm, we define the neighborhood set of the cell space and improve the operation paradigm of neighborhood computation, transition probability calculation, and cell state transition. The experiments undertaken in this study demonstrate that the vectorized algorithm can greatly reduce the computation time, especially in the environment of a vector programming language, and it is possible to parallelize the algorithm as the data volume increases. The execution time for the simulation of 5-m resolution and 3 × 3 neighborhood decreased from 38,220.43 s to 803.36 s with the vectorized algorithm and was further shortened to 476.54 s by dividing the domain into four computing units. The experiments also indicated that the computational efficiency of the vectorized algorithm is closely related to the neighborhood size and configuration, as well as the shape of the research domain. We can conclude that the combination of vectorization and parallel computing technology can provide scalable solutions to significantly improve the applicability of urban CA.     

复杂网络视角下的城市人流空间概念模型与研究框架

城市内人流特征研究一直是城市地理学和城市空间研究的重要领域之一.针对已有相关研究存在仅侧重于从人口规模、密度视角分析空间分布及格局特征,而对隐藏于空间分布背后,因人流动而建立的空间交互关系关注不足的问题.本文以流空间理论、复杂网络理论、空间行为交互理论为理论基础,立足基于流、网络剖析城市内部空间中各要素间的相互作用及关...     

Estimation of ocean primary productivity and its spatio-temporal variation mechanism for East China Sea based on VGPM model

According to calculation results of ocean chlorophyll concentration based on SeaWiFS data by SeaBAM model and synchronous ship-measured data, this research set up an improved model for CaseⅠand CaseⅡwater bodies respectively. The monthly chlorophyll distribution in the East China Sea in 1998 was obtained from this improved model on calculation results of SeaBAM. The euphotic depth distribution in 1998 in the East China Sea is calculated by using remote sensing data of K490 from SeaWiFS according to the relation between the euphotic depth and the oceanic diffuse attenuation coefficient. With data of ocean chlorophyll concentration, euphotic depth, ocean surface photosynthetic available radiation (PAR), daily photoperiod and optimal rate of daily carbon fixation within a water column, the monthly and annual primary productivity spatio-temporal distributions in the East China Sea in 1998 were obtained based on VGPM model. Based on analysis of those distributions, the conclusion can be drawn that there is a clear bimodality character of primary productivity in the monthly distribution in the East China Sea. In detail, the monthly distribution of primary productivity stays the lowest level in winter and rises rapidly to the peak in spring. It gets down a little in summer, and gets up a little in autumn. The daily average of primary productivity in the whole East China Sea is 560.03 mg/m2/d, which is far higher than the average of subtropical ocean areas. The annual average of primary productivity is 236.95 g/m2/a. The research on the seasonal variety mechanism of primary productivity shows that several factors that affect the spatio-temporal distribution may include the chlorophyll concentration distribution, temperature condition, the Yangtze River diluted water variety, the euphotic depth, ocean current variety, etc. But the main influencing factors may be different in each local sea area.     

基于GIS场模型的城市餐饮服务热点探测及空间格局分析

餐饮服务是城市生活的重要组成部分,提取城市餐饮服务热点并识别其空间分布模式,对于理解城市形态结构具有重要意义。针对过去基于POI进行城市形态特征定量分析的不足,利用GIS场模型对城市特征要素的空间分布模式进行识别,并采用地学信息图谱对其模式进行可视化和分析。以济南市主城区4.71万个餐饮服务POI作为主要数据源,首先基于密度场热点探测模型提取餐饮服务热点并按照密度值进行等级划分;然后采用广义对称结构图谱和数字场层次结构图谱表达餐饮服务热点的空间分布结构特征和规模等级结构特征,并构建其分布模式图谱;最后对结果展开讨论。研究表明：① 数字场热点探测模型能够有效地从POI中识别出不同等级的热点。② 广义对称结构图谱和基于GIS场模型的层级结构图谱能够分别从纵横两个方面分析和表达餐饮热点的空间分布结构和层次等级结构特征。综上所述,本研究为基于POI的城市特征要素提取和城市形态研究提供了一种有效的定量分析思路,其方法也可以推广至其他城市特征要素的提取、分析和表达当中。     

东海初级生产力遥感反演及其时空演化机制

According to calculation results of ocean chlorophyll concentration based on SeaWiFS data by SeaBAM model and synchronous ship-measured data, this research set up an improved model for Case I and Case Ⅱ water bodies respectively. The monthly chlorophyll distribution in the East China Sea in 1998 was obtained from this improved model on calculation results of SeaBAM. The euphotic depth distribution in 1998 in the East China Sea is calculated by using remote sensing data of K490 from SeaWiFS according to the relation between the euphotic depth and the oceanic diffuse attenuation coefficient. With data of ocean chlorophyll concentration, euphotic depth, ocean surface photosynthetic available radiation (PAR), daily photoperiod and optimal rate of daily carbon fixation within a water column, the monthly and annual primary productivity spatio-temporal distributions in the East China Sea in 1998 were obtained based on VGPM model. Based on analysis of those distributions, the conclusion can be drawn that there is a clear bimodality character of primary productivity in the monthly distribution in the East China Sea. In detail, the monthly distribution of primary productivity stays the lowest level in winter and rises rapidly to the peak in spring. It gets down a little in summer, and gets up a little in autumn. The daily average of primary productivity in the whole East China Sea is 560.03 mg/m^2/d, which is far higher than the average of subtropical ocean areas. The annual average of primary productivity is 236.95 g/m^2/a. The research on the seasonal variety mechanism of primary productivity shows that several factors that affect the spatio-temporal distribution may include the chlorophyll concentration distribution, temperature condition, the Yangtze River diluted water variety, the euphotic depth, ocean current variety, etc. But the main influencing factors may be different in each local sea area.     

Methods for calculating glacier area and length in a mountainous area based on remote-sensing data and a digital elevation model

In a mountainous region, the glacier area and length extracted form the satellite imagery data is the projected area and length of the land surface, which can’t be representative of the reality; there are always some errors. In this paper, the methods of calculating glacier area and length calculation were put forward based on satellite imagery data and a digital elevation model (DEM). The pure pixels and the mixed pixels were extracted based on the linear spectral un-mixing approach, the slop of the pixels was calculated based on the DEM, then the area calculation method was presented. The projection length was obtained from the satellite imagery data, and the elevation differences was calculated from the DEM. The length calculation method was presented based on the Pythagorean theorem. For a glacier in the study area of western Qilian Mountain, northwestern China, the projected area and length were 140.93 km2 and 30.82 km, respectively. This compares with the results calculated by the methods in this paper, which were 155.16 km2 and 32.11 km respectively, a relative error of the projected area and length extracted from the LandSat Thematic Mapper (TM) image directly reach to -9.2 percent and -4.0 percent, respectively. The calculation method is more in accord with the practicality and can provide reference for some other object’s area and length monitoring in a mountainous region.     

安塞县退耕还林工程与农业生态经济社会系统协同效应的分析——基于VAR模型的实证分析

针对黄土丘陵区退耕还林工程与农业生态经济社会系统协同性研究滞后的现实,运用向量自回归模型(VAR),通过对安塞县1995–2014年相关数据的分析,明确了其协同效应。退耕还林工程结果表明:退耕还林工程对农业生态经济社会系统产生作用的同时,农业生态经济社会系统的改变也反作用于退耕还林工程,明确了退耕还林工程与农业生态经济社会系统之间存在协同互馈的效应。在这一协同过程中,退耕还林工程对农业生态系统的贡献率达34%,明显高于退耕对农业经济系统、农业社会系统的贡献率;农业经济系统对退耕还林工程的影响程度最为明显,贡献率最高点达55.3%且常年稳定,这些都与现实状况相一致。基于此,为了推进退耕还林工程与农业生态经济社会系统的优化耦合,需要在增强生态功能基础上,通过发展碳汇产业促使生态功能的经济显化,构建以提高区域内资源的有效利用率为核心的农业产业–资源链。     

基于MCR模型和DO指数的九江滨水城市生态安全网络构建

兼顾生态保护和经济增长的生态安全网络对引导滨水城市走可持续发展道路具有重要指导意义。本文以九江市为例,采用景观生态数据集和产业信息数据集,结合最小累积阻力模型（MCR）和连续空间的产业集聚测度指数（DO）构建了综合评价方法,分别对景观生态格局和经济生产空间进行分析,诊断二者的空间冲突确定战略节点并构建生态安全网络。结果表明：① 研究区包含重要生态源地29个,总面积为7323 km²;生态安全阻力高值区面积占39.69%,位于城市中部和东部连片区域,低值区则处于外围,且连通过渡区域较少,呈现空间上两极分化的“中心—外围”景观生态格局;② 经济生产空间临近水资源分布,呈现为小尺度集聚、大尺度分散的空间格局;主要产业集聚区的平均长度和数量均显示出重度污染行业>轻度污染行业>中度污染行业的空间关系;③ 识别出景观生态廊道总长685.57 km,选取了25个生态—经济战略节点,规划了18条总长424.53 km的重要绿带和26条总长662.46 km的一般绿带,共同构成了“蜂巢状”九江市生态安全网络格局。本文采用自然和经济条件相结合的综合分析视角,为生态安全格局的构建提供了多样化的实现途径。