VIIRS/DNB夜间灯光月度产品插补方法对比——以北京为例     

陈慕琳  蔡红艳 《地理科学进展》2019,38(1):126-138

新一代VIIRS/DNB(Visible Infrared Imaging Radiometer Suite Day/Night Band)夜间灯光数据因其具备更精细的时空分辨率、数据不存在饱和现象、不同年份数据可比性强等优点而迅速代替DMSP/OLS(Defense Meteorological Satellite Program's Operational Linescan System)夜间灯光数据成为新的研究热点。但由于杂散光的污染,VIIRS/DNB夏季数据数值缺失严重,致使数据在空间和时间上不连续,因此,插补缺失数据成为后续应用的前提。鉴于此,论文从插补结果异常值、与参照值对比、计算性能三个方面,系统比较了三次样条插值(样条)、三次Hermite插值(Hermite)、灰色预测模型(GM)、三次指数平滑法(指数)4种插补方法的适用性,以期为插补VIIRS/DNB夜间灯光数据提供方法选择的依据。研究结果表明：①异常值比较方面,Hermite法未出现异常值,另外3种算法仅出现少量异常值(0.02%~1.34%);②与参照值的对比方面,Hermite法与参考值接近程度最高,GM接近程度最低,样条法和指数法介于两者中间;③算法性能比较方面,4种方法都具备计算简单、容易编程的特点,但指数法的算法时长是另外3种方法的10倍以上。因此,综合多方表现,当插补月份前后两侧均有足够长的原始数据时,插补效果好、计算速度快、不会出现过冲现象的Hermite法最适宜,样条法次之;当插补月份仅单侧有足够长的数据时,适宜采用指数法(插补效果好、计算速度较慢)或GM(插补效果偏低、计算速度快)进行插补。  相似文献   

基于自然间断点分级法的土地利用数据网格化分析   总被引：4，自引：0，他引：4  

李乃强  徐贵阳 《测绘通报》2020,(4):106

土地利用在自然资源统一管理中扮演着重要角色，面对不同区域和年份的数据，统一分析比对口径尤为重要，同时也应反映出相互之间的差异。本文以宜兴市2009年和2017年土地利用现状数据为数据源，首先使用统一的分类标准提取用地类型中的3大类，通过不同大小的单元划分尝试和结果分析，发现适用于该数据的网格尺度大小；然后基于自然间断点分级法进行分级范围划定，对宜兴市三类用地类型的分布和变化趋势进行综合分析，较为真实地反映了宜兴市用地情况；最后通过选用合适的空间尺度和分级范围划定方法，进而构建一个兼具操作性和科学性的土地利用数据网格化方法，为自然资源部门统筹管理和综合治理提供依据。  相似文献   

地面沉降监测多源数据融合分析   总被引：2，自引：1，他引：1  

刘胜男  陶钧  卢银宏 《测绘通报》2020,(12):46-49

地面沉降是区域性地面高程下降的一种地质现象，一般是由自然因素和人为因素的共同作用导致的。目前地面沉降监测的方法很多，各有优劣。本文结合武进中心城区地面沉降监测系列工程案例，对不同沉降监测方法产生的多源数据进行了分析、对比和融合，使成果兼具各种方法的优点，其不仅能更好地描述地面沉降的现状及预测地面沉降的发展趋势，而且可为后期地面沉降监测提供更加准确且丰富的数据基础。  相似文献   

不同测站点云数据的配准算法     

高益忠 《北京测绘》2020,(2):180-184

随着三维激光扫描技术的发展,利用三维激光扫描仪采集信息,构建三维模型成为了热门的课题。由于受到观测环境、观测方向等影响,无法一次性地获得物体的所有的点云数据。因此,不同视角下点云数据的配准成为了三维建模中的关键技术,直接影响了最终的重合结果以及模型精度。本文着重研究主方向贴合法和最近点迭代算法(ICP算法),基于matlab平台编写算法,并对算法进行研究,得出配准结果以及配准精度。  相似文献   

基于广义回归神经网络的全球表层海水1°×1°二氧化碳分压数据推演     

钟国荣  李学刚  曲宝晓  王彦俊  袁华茂  宋金明 《海洋学报》2020,42(10):70-79

表层海水二氧化碳分压是评估海洋碳源汇强度的关键参数，但其实测数据较少、时空分布极不均匀，导致二氧化碳交换通量的估算有很大的不确定性，海洋源汇特征就不能确切获取。为了解决这个难题，在收集的表层大洋二氧化碳地图(Surface Ocean CO₂ Atlas，SOCAT)实测数据集基础上，运用广义回归神经网络建立二氧化碳分压与经纬度、时间、温度、盐度和叶绿素浓度间的非线性关系，构建了1998?2018年间全球1°×1°经纬度的表层海水二氧化碳分压格点数据，其标准误差为16.93 μatm，平均相对误差为2.97%，优于现有研究中的前反馈神经网络、自组织映射神经网络和机器学习算法等方法。根据构建的数据所绘制的全球表层海水二氧化碳分压的分布与现有研究有较好的一致性。  相似文献   

基于与Jason-2数据比对的Jason-3卫星高度计全球数据质量评估   总被引：1，自引：1，他引：0  

刘治中  杨俊钢  张杰  崔伟 《海洋学报》2020,42(3):129-139

Jason-3卫星高度计于2016年1月17日成功发射，2016年2月12日进入预定轨道，与Jason-2高度计同轨进入编队飞行阶段，并落后Jason-2高度计约1分20秒，两者相距约560 km。2016年9月1日，Jason-2高度计变换轨道，编队飞行阶段结束，两高度计进入平行轨道，以增加卫星高度计对地观测的空间覆盖。本研究主要开展了Jason-3高度计的数据质量的评估与检验，包括Jason-3高度计数据可用性和有效性的验证，以及Jason-3高度计和校正辐射计各参数的数据质量监测。重点开展了Jason-2与Jason-3高度计各项参数的综合比较，利用Jason-2与Jason-3高度计编队飞行阶段的数据精确评估了两高度计参数的一致性，并从全球数据角度分析了Jason-3高度计获取各参数的能力以及稳定性；通过与Jason-2互交叉点比较分析评估Jason-3高度计海面高度数据质量情况，验证Jason-3高度计数据精度。结果表明，Jason-3高度计的数据质量满足高度计测高的要求，具有与Jason-1、Jason-2、T/P等高度计相同或更高的测高精度以监测全球海平面变化，此外，Jason-3有效波高参数数据质量明显优于Jason-2高度计。  相似文献   

Hierarchical community detection and functional area identification with OSM roads and complex graph theory     

Ye Hong 《International journal of geographical information science》2019,33(8):1569-1587

An in-depth analysis of the urban road network structure plays an essential role in understanding the distribution of urban functional area. To concentrate topologically densely connected road segments, communities of urban roads provide a new perspective to study the structure of the network. In this study, based on OpenStreetMap (OSM) roads and points-of-interest (POI) data, we employ the Infomap community detection algorithm to identify the hierarchical community in city roads and explore the shaping role roads play in urban space and their relation with the distribution of urban functional areas. The results demonstrate that the distribution of communities at different levels in Guangzhou, China reflects the urban spatial relation between the suburbs and urban centers and within urban centers. Moreover, the study explored the functional area characteristics at the community scale and identified the distribution of various functional areas. Owing to the structure information contained in the identification process, the detected community can be used as a basic unit in other urban studies. In general, with the community-based network, this study proposes a novel method of combining city roads with urban space and functional zones, providing necessary data support and academic guidance for government and urban planners.  相似文献   

不同插值方法在海域气象参数估算中的可靠性评价          下载免费PDF全文

艾葳  万继敏  崇元 《海洋技术学报》2019,38(2)

海域条件下的气象观测具有数据稀少、变化大且观测站点分布不均的特点,其插值精度受插值方法影响较大。首先对常规插值方法进行理论分析,进而选取了反距离加权法、克里金法和样条函数法三种插值方法进行了插值实验和精度分析。根据渤海湾某区域的气象历史数据,采用不同方法绘制了温度、压强和湿度的插值平面图,并基于交叉验证的方式对各插值方法进行了对比,给出了不同方法的插值估算可靠性评价。结果表明:温度、压强和湿度的插值精度均是基于反距离加权法的插值结果最优(MAE_(温度)=2.42,RMSE_(温度)=1.92,MAE_(压强)=2.05,RMSE_(压强)=1.30,MAE_(湿度)=11.394, RMSE_(压强)=6.43),同时基于反距离加权法的图形绘制可视化效果也要优于其他两种方法。研究结果可为海域气象参数估算提供理论和实践依据。  相似文献   

APPLYING 3D INVERSION OF SINGLE-PROFILE MAGNETOTELLURIC DATA TO IDENTIFY THE SHADE AND YUNONGXI FAULTS          下载免费PDF全文

JIANG Feng  CHEN Xiao-bin  DONG Ze-yi  CUI Teng-fa  LIU Zhong-yin  WANG Pei-jie 《地震地质》2019,41(6):1444-1463

Many synthetic model studies suggested that the best way to obtain good 3D interpretation results is to distribute the MT sites at a 2D grid array with regular site spacing over the target area. However, MT 3D inversion was very difficult about 10 years ago. A lot of MT data were collected along one profile and then interpreted with 2D inversion. How to apply the state-of-the-art 3D inversion technique to interpret the accumulated mass MT profiles data is an important topic. Some studies on 3D inversion of measured MT profile data suggested that 2D inversions usually had higher resolution for the subsurface than 3D inversions. Meanwhile, they often made their interpretation based on 2D inversion results, and 3D inversion results were only used to evaluate whether the overall resistivity structures were correct. Some researchers thought that 3D inversions could not resolute the local structure well, while 2D inversion results could agree with the surface geologic features much well and interpret the geologic structures easily. But in the present paper, we find that the result of 3D inversion is better than that of 2D inversion in identifying the location of the two local faults, the Shade Fault(SDF)and the Yunongxi Fault(YNXF), and the deep structures. In this paper, we first studied the electrical structure of SDF and YNXF based on a measured magnetotelluric(MT) profile data. Besides, from the point of identifying active faults, we compared the capacity of identifying deep existing faults between 2D inversion models and 3D models with different inversion parameters. The results show that both 2D and 3D inversion of the single-profile data could obtain reasonable and reliable electrical structures on a regional scale. Combining 2D and 3D models, and according to our present data, we find that both SDF and YNXF probably have cut completely the high resistivity layer in the upper crust and extended to the high conductivity layer in the middle crust. In terms of the deep geometry of the faults, at the profile's location, the SDF dips nearly vertically or dips southeast with high dip angle, and the YNXF dips southeast at depth. In addition, according to the results from our measured MT profile, we find that the 3D inversion of single-profile MT data has the capacity of identifying the location and deep geometry of local faults under present computing ability. Finally, this research suggests that appropriate cell size and reasonable smoothing parameters are important factors for the 3D inversion of single-profile MT data, more specifically, too coarse meshes or too large smoothing parameters on horizontal direction of 3D inversion may result in low resolution of 3D inversions that cannot identify the structure of faults. While, for vertical mesh size and data error thresholds, they have limited effect on identifying shallow tectonics as long as their changes are within a reasonable range. 3D inversion results also indicate that, to some extent, adding tippers to the 3D inversion of a MT profile can improve the model's constraint on the deep geometry of the outcropped faults.  相似文献   

A Review of the Calculation Formula for the Four-component Borehole Strainmeter and Application to Earthquake Cases   总被引：1，自引：0，他引：1  

SU Kaizhi 《中国地震研究》2019,33(1):132-146

Based on the principle formula for the four-component strainmeters, we can directly obtain the specific plane strain, shear strain and azimuthal angle of the principal strain, and the maximum and minimum principal strains calculated afterwards are the indirect result. The problems of practicality of the sensitivity coefficients A and B of plane strain and shear strain are then discussed. Based on this idea, we analyzed the observation data of several four-component borehole strainmeters near the epicenter of the Yiliang M_S5.7 earthquake in 2012 and the Ludian M_S6.5 earthquake in 2014 in the Zhaotong area, Yunnan Province. The results show that the analysis based on the perspective of plane strain and shear strain has an obviously better effect than that based on the component readings, and can directly peel off the respective abnormality of the plane strain and shear strain. In addition, the correlation coefficient curves between measured data of two plane strains show significant anomalies which often occur several days before and during the earthquake.  相似文献