An Electronic Chart Display and Information System     

Xiaoxia Wan  Chaohua Gan  Chun Huang 《Marine Geodesy》2005,28(2):175-189

This article introduces the most advanced form of electronic chart display and information systems (ECDIS) which complies with the performance standards for ECDIS established by the International Maritime Organization (IMO) and International Hydrographic Organization (IHO). It also describes the key features and the important functions of ECDIS, which we developed. This system is different from the productions developed by C-map, Seven-cs, offshore, and others. It is more suitable for China Marine Safety Administration Bureau to manage the navigation marks real-time. Using this system charts were located and accessed rapidly, and displayed smoothly. This article also discusses in ECDIS application system how to dynamically access and desert charts data in a limited memory (limited computer memory and resource). We constructed a tridimensional structure to manage a large amount of charts data. Vertically, according to the scale range, all charts were divided into eight levels, and a data structure called as “Multiple Scale Quad-tree” was constructed. And horizontally, a grid (every unit has a fixed size) was given to a certain scale level. We call this data structure a “Regular Page.” We explore the implementation of such a structure on the worldwide charts management utilizing quad-trees. Then we discuss the future development of ECDIS and its application system in marine agencies in China.  相似文献   

土地复垦地籍调绘及数据处理中的MATLAB方法   总被引：1，自引：0，他引：1  

付江缺  段春燕  吴春 《测绘工程》2008,17(6)

以江苏省徐州市贾汪区为研究对象,详述矿区土地复垦中地籍测量的全过程;以JSCORS技术和全站仪相结合的野外作业方式大大提高数据采集的速度,深入讨论全站仪野外作业记录格式与CASS6.0不一致时数据的转换问题,详细分析MATLAB与其他传统的编程方式比较所体现出来的优越性。  相似文献   

GPS虚拟参考站RTCM传输电文的分析与解码   总被引：1，自引：0，他引：1  

孙良育  刘春  吴杭彬 《全球定位系统》2008,33(5):52-57

网络RTK中流动站和数据处理中心间的数据传输是通过RTCMSC-104标准进行的,新的数据版本RTCM3.X是一种高效、简洁的格式。分析了RTCMSC-104版本3的数据结构和类型,提出了一种解码和校验的方法。通过编写C#程序进行解码,对校园虚拟参考站的数据进行了解码测试,表明本解码方法精确可靠。  相似文献   

江苏新沂市露采矿山地质环境现状及恢复治理措施          下载免费PDF全文

杨小川  张春 《江苏地质》2008,32(2):144-147

新沂市的矿产资源开发利用程度低,潜力大,矿山开采规模小、资源浪费严重,采矿毁坏土地和植被,破坏生态环境,对自然地貌景观破坏严重;采矿掘进面高差大,边坡陡立,埋下诱发山体崩塌、滑坡等地质灾害隐患,易造成人员伤亡事故;露采矿山地质环境整治滞后,绝大多数露采矿山地质环境没有得到有效整治。根据露采矿山开采中存在的问题,提出了包括管理措施、工程技术措施和经济政策措施等地质环境恢复治理措施。  相似文献   

The Potential of Maps APIs for Internet GIS Applications   总被引：2，自引：0，他引：2  

T Edwin Chow 《Transactions in GIS》2008,12(2):179-191

Since the launching of Maps Application Programming Interfaces (APIs) in 2005, many web developers, including geographers and non‐geographers, applauded the freely adaptable tools and used them to spawn numerous Internet applications. The success of the Maps APIs is largely attributable to its no‐cost policy, the availability of global data coverage, dynamic navigation, query capability, and ease of implementation. Despite its versatility in dynamic exploration of geographic data online, the existing Maps APIs lack Geographic Information System (GIS) functionalities compared to other Internet Mapping Services. The goal of this research was to review the potential of the Maps APIs for Internet GIS applications. This research employed the Google Maps API and developed a web prototype that disseminates spatial information of urban sprawl in Mundy Township, Michigan. The results revealed that both vector and raster data could be effectively represented by using the Maps API. Moreover, the Geographic Markup Language (GML) approach illustrated great potential for developing Internet GIS solutions around open specifications. This research suggested several potential solutions to expand the spectrum of GIS operations of the Maps APIs by incorporating the XML‐related technology and extending the JavaScript library.  相似文献   

Surface complexation modeling of Cu(II) adsorption on mixtures of hydrous ferric oxide and kaolinite     

Tracy J Lund  Carla M Koretsky  Christopher J Landry  Melinda S Schaller  Soumya Das 《Geochemical transactions》2008,9(1):9

Background  

The application of surface complexation models (SCMs) to natural sediments and soils is hindered by a lack of consistent models and data for large suites of metals and minerals of interest. Furthermore, the surface complexation approach has mostly been developed and tested for single solid systems. Few studies have extended the SCM approach to systems containing multiple solids.  相似文献   

江西长江河道演变及其对水患灾害形成的影响   总被引：1，自引：0，他引：1  

马逸麟  张然  诸葛春  王志强 《地质灾害与环境保护》2008,19(2):24-28

对江西长江河道的演变特征进行了详细研究,基本查清了近代江西长江河道的发展演变历程。自清代以来未发生重大的变迁事件,但其也处于不断演变中,其演变主要表现在河道的冲淤作用,即岸线的冲刷侧蚀后退和边滩的淤胀,江心洲、心滩、浅滩的增生淤胀、消亡和移动,河道的淤塞等。为研究洪涝灾害成生背景、致灾作用,以及防灾治灾提供科学依据。  相似文献   

电子政务空间信息服务应用模型的适用性评价     

周娜  刘纪平  董春  王勇 《测绘通报》2008,(12):64-67

在总结国内外相关模型评价方法和分析电子政务空间信息服务应用模型的基础上,提出一种基于多层次、可扩展评价指标体系的适用度评价模型,并给出适用度计算的方法和流程。最后,以三种地震灾害评估模型在震灾评估中的应用为例对其进行基于适用度的模型适用性评价。  相似文献   

Height dependence of the amplitudes of solar oscillations viewed with a potassium resonance scattering spectrometer     

Christopher J. Underhill  Clive C. Speake 《Solar physics》1996,163(2):231-240

Over the course of the year, the variation in the solar line-of-sight velocity causes a change in the heights in the photosphere which are analysed by the red and blue passbands of a resonance scattering spectrometer. This in turn would be expected to produce a variation in the ratio of acoustic amplitudes measured in each passband. Using data from the Tenerife spectrometer of the Birmingham Solar Oscillations Network (BiSON), we demonstrate such a seasonal change. We then use the Eddington-Barbier approximation and an atmospheric model to convert the magnitude of this trend in velocity ratio with line-of-sight velocity into an approximate value of 580 km for the velocity-amplitude scale height. However, a simple argument suggests that Doppler imaging causes this to be an overestimate of the true value.  相似文献   

Micromechanics of the velocity and normal stress dependence of rock friction   总被引：1，自引：0，他引：1  

Weibin Wang  Christopher H. Scholz 《Pure and Applied Geophysics》1994,143(1-3):303-315

Among the second-order effects on friction the most important are those of variable normal stress and of slip velocity. Velocity weakening, which is usually considered the source of the stick-slip instability in rock friction, has been observed in velocity stepping experiments with Westerly granite. The friction change, , was –0.01 to –0.008 for a tenfold velocity increase. Using normal closure measurements, we observed dilation upon each increase in sliding rate. We also observed, for the first time, time-dependent closure between surfaces during static loading. The dilation that occurred during the velocity stepping experiment was found to be that expected from the static time-dependent closure phenomenon. This change in closure was used to predict friction change with an elastic contact model. The calculated friction change which results from a change in contact area and asperity interlocking, is in good agreement with the observed velocity dependence of steady-state friction. Variable normal stress during sliding has two effects, first in creating new partial slip contacts and locking some existing fully sliding contacts and second in increasing interlocking, for instance when normal load is suddenly increased. As a result, a transient change in friction occurs upon a sudden change in normal load.  相似文献