Exploring the Hidden Potential of Common Spatial Data Models to Visualize Uncertainty

Common Spatial Data Models (SDMs) such the vector, raster, and quadtree have well understood and widely practiced conventions of storage and visualization. This paper explores what happens when the conventions of visualization are not strictly adhered to, and the SDMs are used in an atypical fashion. A framework based on a quasi similarity measure is presented, which quantifies (in terms of "distance") the relationship between the storage format and the visualization output, following an accepted protocol. This research used a transformation process (Tp) to define this distance. Then, the atypical use of the quadtree SDM to represent choropleth spatial boundary uncertainty and attribute uncertainty was quantified using the same framework. This research shows that if a SDM is used outside of its original context, then the distance between the storage format and its visual output can alter; in our case, the distance decreased. This result was interpreted as evidence for the creation of a new spatial data structure. The formalization of the relationship between an SDM and its visual output will be valuable for future exploration of the non-conventional visualization of common SDMs.     

Opportunities for Use of the Spatial Data Transfer Standard at the State and Local Level

Dramatic changes in the way that spatial data have been collected and processed over that last 20 years is leading to a rethinking and restructuring on the most efficient ways to handle geographical information. These changes are taking place at the federal, state, and local governmental levels with great potential for the private sector as well. The formal adoption of the Spatial Data Transfer Standard (SDTS) as the federal database transfer standard for spatial databases signals a new era in this long chain of developments. It offers more flexible and efficient database transfers than earlier tools, and will become the workhorse for implementing the new National Spatial Data Infrastructure. It offers organizations a standard that will make possible and practical a much wider sharing of databases than is currently being done today. Use of the SDTS presents an opportunity to many organizations to share data more easily and reduce the duplication of expensive spatial database resources.     

浅论哈尔滨市基础空间地理信息系统建设--谈组件式GIS的现状与未来

立足于组件式GIS技术,结合哈尔滨市基础空间地理信息系统的建设与实施,阐述了利用组件式GIS平台进行GIS建设的方式、方法以及采用该方法的优势、现状和未来的发展趋势等内容。     

东南沿海地理国情普查影像解译应用分析

影像解译是地理国情普查过程中一项重要的基础性工作,影像解译的结果直接影响作业质量、效率.本文选择东南沿海地区具有典型特征的影像,结合我省正在开展的地理国情普查实践,分别采用目视解译、自动解译和人机交互解译三种方法进行解译,从解译精度、效率、应用条件等方面,对比分析了三种方法的优缺点,结果表明:三种解译方法各具优势和不足,解译结果与影像质量、辅助数据质量、地形复杂程度、地物种类等有密切关系,在实际地理国情普查过程中须综合考虑使用.     

On the Uncertainty of Local Shape of Lines and Surfaces

Modeling line or surface phenomena digitally involves two tasks: discretization of the phenomenon, which yields a finite set of data, and subsequent interpolation, which reconstructs the continuum. Many mathematical techniques exist for the latter task, and most methods require a number of parameters to be specified. The shape of digital line or surface models between the data points (that is, the local shape) and the information derived from these models both depend on the selected method and, possibly, on the specification of parameters. The reconstruction of the continuum thus introduces uncertainty. This paper examines the sources and effects of this type of uncertainty. For this purpose, the modeling of lines and surfaces is separated into an abstraction, an implementation, and measurement. The individual factors affecting uncertainty of local shape in each step are identified and discussed. The paper concludes that local shape uncertainty, unlike positional uncertainty of given data, cannot be numerically assessed. Instead, measures of plausibility have to be used to denote the quality of digital models of lines and surfaces. Finally, the concept and potential problems of future empirical investigations are discussed.     

网格技术研发情况综述

网格是继互联网的前两个浪潮Internet和Web之后的第三次浪潮,迅速受到全世界的瞩目。美国、欧洲、日本、韩国、中国等都启动了大型网格研究计划,并得到了产业界的支持。综述了各国网格技术研发情况。     

铁路测量中坐标系的建立与转换

在铁路测量中,长度投影变形要求小于2．5cm／km。但是由于铁路为典型的线性工程,通常横跨多个投影带,因此采用国家标准3。带难以满足铁路测量精度要求,本文通过分析高斯投影长度变形,提出分段建立独立坐标系的方法,控制长度投影变形,满足精度要求,最后介绍利用GlobalMapper软件实现两个独立坐标系的转换。     

农村集体土地地籍调查的实践与探索

农村集体土地确权登记发证工作,应以满足国家基本要求为前提,本着最大限度地利用已有成果资料,减轻外业劳动强度,提高工作效率,减少资金投入的原则,创新集体土地所有权、集体建设用地和宅基地使用权地籍调查方法。为此,在武汉市农村集体土地地籍调查试点中进行了实践与探索。     

RTK技术在送变电线路测量中的应用

在简介RTK技术的基础上,分析和研究了RTK技术在送变电工程测量中各阶段的主要应用,提出了具体的应用方法,指出了应用中应注意的主要问题与解决的技术措施,对工程应用具有一定的指导意义。     

地理国情普查工作报表的特性与作用研究

地理国情普查工作报表是地理国情普查项目管理的基本措施和途径,本文对地理国情普查工作报表的特性和作用进行了论述,以期对从事地理国情普查的生产单位和管理单位起到指导作用。     

“工程测量”实践教学体系的研究与构建

工程测量是港口航道与海岸工程专业技术人员必须掌握的基本技能之一。为解决应用型本科院校工程测量课程的实践教学体系与应用型人才培养目标要求不相适应的问题,从剖析实践教学过程中存在的现实问题出发,结合学校及专业实际情况,以大连海洋大学港口航道与海岸工程专业为例,提出了一套完整的、操作性强、专业特色鲜明的实践教学体系,并取得了一定的教学成果,对于普通高等学校应用型人才的培养具有重要的借鉴意义。     

Assessment of satellite ocean color products of MERIS,MODIS and SeaWiFS along the East China Coast (in the Yellow Sea and East China Sea)

The validation of satellite ocean-color products is an important task of ocean-color missions. The uncertainties of these products are poorly quantified in the Yellow Sea (YS) and East China Sea (ECS), which are well known for their optical complexity and turbidity in terms of both oceanic and atmospheric optical properties. The objective of this paper is to evaluate the primary ocean-color products from three major ocean-color satellites, namely the Moderate Resolution Imaging Spectroradiometer (MODIS), Medium Resolution Imaging Spectrometer (MERIS), and Sea-viewing Wide Field-of-view Sensor (SeaWiFS). Through match-up analysis with in situ data, it is found that satellite retrievals of the spectral remote sensing reflectance R_rs(λ) at the blue-green and green bands from MERIS, MODIS and SeaWiFS have the lowest uncertainties with a median of the absolute percentage of difference (APD_m) of 15–27% and root-mean-square-error (RMS) of 0.0021–0.0039 sr⁻¹, whereas the R_rs(λ) uncertainty at 412 nm is the highest (APD_m 47–62%, RMS 0.0027–0.0041 sr⁻¹). The uncertainties of the aerosol optical thickness (AOT) τ_a, diffuse attenuation coefficient for downward irradiance at 490 nm K_d(490), concentrations of suspended particulate sediment concentration (SPM) and Chlorophyll a (Chl-a) were also quantified. It is demonstrated that with appropriate in-water algorithms specifically developed for turbid waters rather than the standard ones adopted in the operational satellite data processing chain, the uncertainties of satellite-derived properties of K_d(490), SPM, and Chl-a may decrease significantly to the level of 20–30%, which is true for the majority of the study area. This validation activity advocates for (1) the improvement of the atmosphere correction algorithms with the regional aerosol optical model, (2) switching to regional in-water algorithms over turbid coastal waters, and (3) continuous support of the dedicated in situ data collection effort for the validation task.     

地理国情普查外业调绘系统关键技术及实现

介绍了基于Android的地理国情普查外业调绘系统实现数据采集、离线存储的开发技术和实现方法;实现了影像数据和内业解译数据的浏览、查询、核查及GPS定位以及与数据库同步更新等功能。转变传统纸质调绘方式,起到提高效率,降低成本和有效控制信息获取质量的重要作用。     

LIDAR测量技术在公路测设中的应用分析

公路是线性工程,适于航测与LIDAR技术进行测设,以提供DLG,DEM,DOM产品。航空摄影后处理周期较长,需要几个月甚至更长时间,影响测设任务进程,而LIDAR技术能够弥补这些缺陷,提高工程效率的同时提高工程质量。本文采用LIDAR技术进行分析,并且与以往的航测摄影进行比较,得出一些有益的成果。     

我国城市测量技术发展现状与成就

介绍我国城市测量技术发展的现状,着重介绍测绘新技术在城市测量中的应用与实际效果,阐述测量技术基础建设的成就。     

第二次土地调查数据库成果在土地勘测定界中的应用

介绍了第二次土地调查数据库成果在勘测定界中的应用,进一步规范了土地勘测定界成果资料,确保了成果质量,真正做到了图、数与实地一致,并通过生产实际探讨了县级土地勘测定界内外业工作方法.     

浅谈辽宁省地理国情普查成果应用及服务方向展望

地理国情主要是指地表自然和人文地理要素的空间分布、特征及其相互关系,是基本国情的重要组成部分。目前,辽宁省已完成第一次全国地理国情普查工作,其成果应满足辽宁省经济社会发展和生态文明建设的需要,提高地理国情信息对政府、企业和公众的服务能力。本文从普查成果体系入手,阐述了辽宁省地理国情普查的成果应用,展望了服务方向。     

关于制作像控电子点之记方法与流程的探讨

主要介绍电子点之记的制作流程及方法,以及所涉及的一些计算机软件和工序中可以自动化处理的程序,对于实现难点也进行了分析及说明,使像片控制测量点之记制作的流程更为简便,成果更为可靠。     

双鸭山市连续运行卫星定位服务系统(SYS-CORS)暨南方NRS系统的建设及应用

论述了双鸭山市测绘行业对双鸭山市连续运行卫星定位服务系统(SYS-CORS)暨南方NRS系统的需求,介绍了系统建设过程,同时介绍了系统测试状况,最后叙述系统的功能、本系统的创新点及系统为社会提供信息服务的前景。