加权最小二乘优化倾斜摄影测量模型矢量化精度方法研究

无人机倾斜摄影测量技术以高精度、高效率、大范围的方式全面感知复杂场景,通过专业的数据采集设备和建模软件恢复三维场景,再进行量测。市场上的三维测图软件大部分是基于立面散点正交原理,不能有效地减弱人工立体测图产生的误差。本文提出一种加权最小二乘直线拟合优化倾斜摄影测量模型矢量化精度的方法,选取南昌市桑海管理委员会部分区域进行地形图数据采集和精度评定,试验表明,采用本文方法所建立的立体测图模型精度提高了2 cm。     

信息时代地图技术美的研究与实践

通过分析现代地图表现形式及存在的问题，探讨了信息时代地图制图技术美的含义和地图技术美的表现形式。并在技术美创新理念指导下，对利用计算机技术和图形图像处理技术来改进地图符号设计，提高地图表现力进行了一些理论探讨和技术尝试．同时也得到了一些有益的启示。     

视频立体观察与数字视频立体测图

详细地介绍了时分制视频立体观察的原理及其在摄影测量领域的具体应用,同时对“基于微机的数字视频立体测图系统”从原理到实践做了初步探讨。     

GRASS数据结构分析

详细分析了ＧＲＡＳＳ的三种数据结构，为设计ＧＲＡＳＳ与其它系统数据格式转换接口提供了基础。     

Heterogeneous characteristics of streambed saturated hydraulic conductivity of the Touchet River,south eastern Washington,USA

Traditionally a streambed is treated as a layer of uniform thickness and low saturated hydraulic conductivity (K) in surface‐ and ground‐water studies. Recent findings have shown a high level of spatial heterogeneity within a streambed and such heterogeneity directly affects surface‐ and ground‐water exchange and can have ecological implications for biogeochemical transformations, nutrient cycling, organic matter decomposition, and reproduction of gravel spawning fish. In this study a detailed field investigation of K was conducted in two selected sites in Touchet River, a typical salmon spawning stream in arid south eastern Washington, USA. In‐stream slug tests were conducted to determine K following the Bouwer and Rice method. For the upper and lower sites, each 50 m long and 9 m wide and roughly 20 m apart, a sampling grid of 5 m longitudinally and 3 m transversely was used. The slug tests were performed for each horizontal coordinate at 0·3–0·45, 0·6–0·75, 0·9–1·05 and 1·2–1·35 m depth intervals unless a shallower impenetrable obstruction was encountered. Additionally, water levels were measured to obtain vertical hydraulic gradient (VHG) between each two adjacent depth intervals. Results indicated that K ranged over three orders of magnitude at both the upper and lower sites and differed between the two sites. At the upper site, K did not differ significantly among different depth intervals based on nonparametric statistical tests for mean, median, and empirical cumulative distribution, but the spatial pattern of K varied among different depth intervals. At the lower site, K for the 0·3–0·45 m depth interval differed statistically from those at other depth intervals, and no similar spatial pattern was found among different depth intervals. Zones of upward and downward water flow based on VHG also varied among different depth intervals, reflecting the complexities of the water flow regime. Detailed characterization of the streambed as attempted in this study should be helpful in providing information on spatial variations of streambed hydraulic properties as well as surface‐ and ground‐water interaction. Copyright © 2009 John Wiley & Sons, Ltd.     

Cosmic‐ray rejection for single spectroscopic CCD images by means of template matching

This article describes a novel algorithm for cosmic‐ray rejection in single spectroscopic CCD images. This algorithm is based on a variation of template matching. It focuses on identifying those pixels belong to spectra, while other conventional algorithms tried to locate the cosmic‐ray hits directly. The main principle is applying template matching to find suspicious blocks, which is followed by surface patching to locate the legitimate pixels accurately. Therefore, the rest pixels are the ones corrupted by cosmic‐ray hits. Meanwhile, almost all the parameters are automatically extracted from the images. Examples of its performance are given for both simulated and observed images. It shows an advantage of significantly low false alarm rate with relatively high detection rate (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

The potential of contribution of mangrove-derived organic matter in intertidal sediments as a proxy of mangrove development in the northern Beibu Gulf

University of Maryland, College Park     

Mid-Late Neoproterozoic rift-related volcanic rocks in China: Geological records of rifting and break-up of Rodinia

Early Cambrian and Mid-Late Neoproterozoic volcanic rocks in China are widespread on several Precambrian continental blocks,which had aggregated to form part of the Rodinia supercontinent by ca.900 Ma....