测绘工程专业认证标准的实践教学探索     

何立恒  陈动  史玉峰 《测绘科学》2017,42(4)

针对测绘工程专业实践教学不足的问题,该文构建了新的实践教学体系。以测绘工程专业认证标准为导向,结合测绘工程专业应用性和实践性强的特点,构建基础型实践、工程型实习、创新型拓展和设计型提高的测绘工程本科专业实践教学体系。从完善实验中心管理模式、建立校内外实践基地、改革实践教学方式、创新实践教学考核方法4个方面全面改革和创新实践教学模式,从优化师资结构、鼓励学生拓展训练、健全实践保障体系3个方面搭建实践教学平台。该实践教学体系使学生的实践能力得到全面提高,培养的人才符合测绘工程专业认证标准。  相似文献   

GGOS对流层延迟产品精度分析及在PPP中的应用     

姚宜斌  徐星宇  胡羽丰 《测绘学报》2017,46(3):278-287

对流层延迟是卫星导航定位的主要误差源,GNSS广域增强需要高精度的对流层延迟产品进行误差修正。对流层延迟可通过GNSS进行实时估计,也可通过融合多源数据的数值气象预报模型获取。IGS发布的全球对流层天顶延迟产品由GNSS解算,其精度可达4mm,时间分辨率为5min,但其分布不均匀,在广袤的海洋区域无数据覆盖。GGOS Atmosphere基于ECMWF 40年再分析资料,可提供1979年以来时间分辨率为6h、空间分辨率为2.5°×2°的全球天顶对流层总延迟格网数据。本文通过2015年全球IGS测站的ZTD资料对GGOS的ZTD产品进行了评估,研究了GGOS Atmosphere对流层延迟产品与IGS发布ZTD资料之间的系统差,通过线性拟合估计出每个测站GGOS-ZTD与IGSZTD系统差系数(包括比例误差a和固定误差b),然后对比例误差a、固定误差b进行球谐展开,建立了两种ZTD数据源之间的系统差模型。选取IGS测站和陆态网测站,对附加系统偏差改正后的GGOSZTD产品对PPP的收敛速度的影响进行研究。本文研究结果表明:GGOS-ZTD与IGS-ZTD间存在系统偏差,其bias平均为-0.54cm;两者之间较差的RMS平均为1.31cm,说明GGOS-ZTD产品足以满足广大GNSS导航定位用户对对流层延迟改正的需要。将改正了系统差后的GGOS-ZTD产品用于ALBH、DEAR、ISPA测站、PALM测站、ADIS测站、YNMH测站、WUHN测站进行PPP试验,发现可明显提高定位收敛速度,尤其是在U方向上,收敛速度分别提高10.58%、31.68%、15.96%、43.89%、51.46%、14.69%、18.40%。  相似文献   

Chalcophile element geochemistry of the Baima layered intrusion, Emeishan Large Igneous Province, SW China: implications for sulfur saturation history and genetic relationship with high-Ti basalts   总被引：1，自引：0，他引：1  

Xiao-Qi Zhang  Xie-Yan Song  Lie-Meng Chen  Song-Yue Yu  Wei Xie  Yufeng Deng  Jia-Fei Zhang  Shu-Guang Gui 《Contributions to Mineralogy and Petrology》2013,166(1):193-209

The Permian Baima mafic layered intrusion, believed to be related to the S-undersaturated Emeishan high-Ti basalts, hosts a giant Fe–Ti-V oxide deposit in the lower part of the intrusion. Uniformly high Cu/Pd (1.9 × 10⁶–6.1 × 10⁴) and low Pd/Zr (<0.1) indicate that the Baima parental magma experienced prior sulfide segregation. Mantle-liked δ³⁴S values and low S/Se values indicate negligible external sulfur addition. Primitive mantle-normalized PGE patterns and MELTS calculations indicate that extensive fractional crystallization (~59 %) of chromite, olivine and pyroxene at depth drove the primitive picritic magma to S saturation. Strong positive correlation between IPGE and PPGE and between PGE and V, Cr and S suggest that magmatic sulfide is the dominant mineral controlling the distribution of PGE in the Baima intrusion. A positive correlation between S and Cr, FeO_T + TiO₂ and V content, together with MELTS calculations, indicate that the parental magma of the Baima intrusion reached a second stage of S saturation in the shallower Baima magma chamber, which was likely triggered by decreasing Fe²⁺ accompanying magnetite precipitation. Primitive mantle-normalized PGE patterns for Baima intrusion rocks display similar trends to high-Ti basalts inside the Panxi area, suggesting that they are comagmatic, and following a similar differentiation trend. However, the lavas erupted before they reached sulfide saturation. The more evolved nature of high-Ti basalts outside the Panxi area indicate that they experienced more extensive pre-eruption fractional crystallization. Further fractional crystallization process led these lavas show more PGE fractionated feature.  相似文献   

1994年8月亚洲季风区水汽的源汇分布和输送   总被引：8，自引：0，他引：8  

周军  薛宇峰  刘宣飞 《热带气象学报》1998,14(1):91-96

用正压原始方程模式,对热带气旋穿越副热带高压的异常路径进行了数值试验,揭示出热带气旋自身特征及其与副高中心的经向距离、副高的位置和强度变化是直接影响热带气旋移动路径的敏感因子。也反映出热带气旋与其邻近的天气尺度的副热带高压以及β效应三者之间非线性相互作用的复杂机制。  相似文献   

General entropy model of line segments uncertainty in GIS     

Yufeng Shi  Wenzhong Shi 《地球空间信息科学学报》2013,16(1):61-66

Spatial data uncertainty can directly affect the quality of digital products and GIS-based decision making. On the basis of the characteristics of randomicity of positional data and fuzziness of attribute data, taking entropy as a measure, the stochastic entropy model of positional data uncertainty and fuzzy entropy model of attribute data uncertainty are proposed. As both randomicity and fuzziness usually simultaneously exist in linear segments, their omnibus effects are also investigated and quantified. A novel uncertainty measure, general entropy, is presented. The general entropy can be used as a uniform measure to quantify the total uncertainty caused by stochastic uncertainty and fuzzy uncertainty in GIS.  相似文献   

ArcGIS与MapGIS在耕地质量等级成果补充完善中的应用比较     

赵红强  张裕凤 《西部资源》2013,(5)

研究目的:探讨ArcGIS与MapGIS在耕地质量等级成果补充完善应用中的功能和特点,以期发挥各自的优势,提高工作效率,增强数据的准确性和结果的科学性.研究方法:在耕地质量等级成果补充完善的实践基础上,从因素图的影像校正、因素图的矢量化、属性赋值及数据管理等方面比较,分析ArcGIS与MapGIS的优势与不足.研究结果:ArcGIS在因素图的影像校正、因素图的矢量化及数据管理上具有比较大的优势;而在耕地分等单元属性赋值上,MapGIS更加方便快捷.研究结论:在耕地质量等级成果补充完善工作中,合理利用ArcGIS与MapGIS的优势功能模块,可以减少工作量,提高工作效率,增强数据的准确性与结果的科学性.  相似文献   

http://www.sciencedirect.com/science/article/pii/S1674987113001370     

Yufeng Deng  Feng Yuan  Taofa Zhou  Chao Xu  Dayu Zhang  Xuji Guo 《地学前缘(英文版)》2015,6(2):141-152

Mineral chemistry,whole-rock major oxide,and trace element compositions have been determined for the Tuerkubantao mafic-ultramafic intrusion,in order to understand the early Paleozoic tectonic evolution of the West Junggar orogenic belt at the southern margin of the Central Asian orogenic belt.The Tuerkubantao mafic-ultramafic intrusion is a well-differentiated complex comprising peridotite,olivine pyroxenite,gabbro,and diorite.The ultramafic rocks are mostly seen in the central part of the intrusion and surrounded by mafic rocks.The Tuerkubantao intrusive rocks are characterized by enrichment of large ion lithophile elements and depleted high field strength elements relative to N-MORB.In addition,the Tuerkubantao intrusion displays relatively low Th/U and Nb/U(1.13—2.98 and 2.53—7.02,respectively) and high La/Nb and Ba/Nb(1.15—4.19 and 37.7—79.82,respectively).These features indicate that the primary magma of the intrusion was derived from partial melting of a previously metasomatized mantle source in a subduction setting.The trace element patterns of peridotites,gabbros,and diorite in the Tuerkubantao intrusion have sub-parallel trends,suggesting that the different rock types are related to each other by differentiation of the same primary magma.The intrusive contact between peridotite and gabbro clearly suggest that the Tuerkubantao is not a fragment of an ophiolite.However,the Tuerkubantao intrusion displays many similarities with Alaskan-type mafic-ultramafic intrusions along major sutures of Phanerozoic orogenic belts.Common features include their geodynamic setting,internal lithological zoning,and geochemistry.The striking similarities indicate that the middle Devonian Tuerkubantao intrusion likely formed in a subduction-related setting similar to that of the Alaskan-type intrusions.In combination with the Devonian magmatism and porphyry mineralization,we propose that subduction of the oceanic slab has widely existed in the expansive oceans during the Devonian around the Junggar block.  相似文献   

The Origin of the Black Shale Series and Bentonites from the Wufeng Formation in the Southwestern Upper Yangtze: Implications for the Convergence of the Yangtze and Cathaysia Blocks in the Late Ordovician     

MIAO Yu  ZHOU Ye  ZHOU Jiaxi  TIAN Yufeng  WU Liang  LI Shizhong  ZHANG Yaotang  WANG Wanneng 《《地质学报》英文版》2022,96(6):1897-1916

Early Paleozoic black organic sediments and bentonites occur widely in the craton basin within the Yangtze block and are generally believed to be genetically related to a specific tectonic setting on the cratonic boundary. However, the intimate relationship between their origins and the dynamic mechanisms are unclear, as exemplified by the genesis of the black shale series and bentonites from the Wufeng Formation during the Ordovician–Silurian transition (OST). In order to reveal the relationship between the Wufeng Formation and the convergence of the Yangtze and Cathaysia blocks (i.e., the intracontinental Kwangsian Orogeny), two stratigraphic sections respectively in Zhaotong area (Northeast Yunnan) and Puyi area (Northwestern Guizhou) that were located in the semi-restricted inner Yangtze Sea during the OST were systematically studied, on the basis of whole-rock geochemical composition, pyrite δ34S (δ34Spy), total organic carbon (TOC), stable Sr isotope, pyrite framboid size distribution and zircon U-Pb age, trace elements. The evidence shows that the paleo-oceanic environment changed significantly at the turn of the early–late Katian and formed the black shale series in the Wufeng Formation. These acritarch assemblages were formed in the transition process of the Upper Yangtze Basin from passive continental margin basin to foreland basin during this interval. Based on previous research on the genetic relationship between black shale series and plate tectonic movement, a basin-mountain evolution model suitable for South China in the Late Ordovician is presented. The two bentonites in the Wufeng Formation with U-Pb ages of 445.5 ± 0.8 Ma and 441.9 ± 2.4 Ma primarily originated from the intermediate–acid volcanic eruption during the collision and convergence between the Yangtze and Cathaysia blocks in the Late Ordovician, the provenance region probably being located in the Jiangnan orogenic belt. Thus, we believe that the appearance of the black shale series and bentonite in the Wufeng Formation at the turn of the early–late Katian may represent the initiation of basin-mountain transformation and the Kwangsian Orogeny in South China, which provides important evidence for the collision and convergence of the Yangtze and Cathaysia blocks in the Late Ordovician.  相似文献   

基于物理模型试验的碎屑流流态化运动特征分析          下载免费PDF全文

龙艳梅  宋章  王玉峰  程谦恭  李坤  吴越 《水文地质工程地质》2022,49(1):126-136

流态化运动是高速远程滑坡的主要运动形式,是揭示高速远程滑坡运动机理的重要基础。基于粒子图像测速（PIV）分析方法,采用物理模型试验对不同粒径组成条件下的颗粒流内部的速度分布、剪切变形及流态特征进行了研究,并对高速远程滑坡流态化运动特征进行了讨论分析。结果表明:碎屑流流态化运动特征与颗粒粒径呈显著的相关性,随着粒径的减小或细颗粒含量的增加,颗粒流底部相对于边界的滑动速度以及整体的运动速度均呈逐渐减小的趋势,颗粒流内部剪切变形程度增加,颗粒的运动形式由“滑动”向“流动”转变;当颗粒粒径较小或细颗粒含量较高时,颗粒流内部剪切速率增大的趋势在颗粒流底部更加显著,反映了粒径减小有助于促进颗粒流内部剪切向底部的集中;在同一颗粒流的不同运动阶段及不同纵向深度,其流态特征具有显著差别,颗粒流前缘及尾部主要呈惯性态,颗粒间以碰撞作用为主,而主体部分则主要呈密集态,颗粒间以摩擦接触作用为主;在颗粒流表面及底部,颗粒间相互作用方式主要是碰撞作用,中间部分则以摩擦作用为主;对于不同粒径的颗粒流,随着粒径的增大或粗颗粒含量的增加,颗粒流内部颗粒的碰撞作用加强,颗粒流整体趋于向惯性态转变。  相似文献   

一种改进的全球对流层天顶延迟模型   总被引：1，自引：1，他引：0  

姚宜斌  胡羽丰  余琛 《测绘学报》2015,44(3):242-249

顾及文献[16]所建立的全球对流层天顶延迟模型GZTD的时间分辨率为24h,为进一步提高GZTD模型的时间分辨率,利用GGOS atmosphere的2002—2009年全球天顶对流层延迟格网时间序列按照其6h的时间分辨率分别建模,再采用三次样条插值计算任意时刻的天顶对流层延迟估值,由此构建了一种时间分辨率更高(6h)的改进的GZTD模型(GZTD-6h)。经过两种模型内符合检验对比分析表明,GZTD-6h模型内符合精度(bias:0.17cm,RMS:3.9cm)优于GZTD(bias:0.17cm,RMS:4.4cm)。使用全球IGS站进行外符合检验,统计结果表明GZTD-6h模型(bias:-0.22cm,RMS:4.05cm)相比GZTD(bias:-0.45cm,RMS:4.51cm)改善明显。  相似文献