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1.
G. R. Hoffman 《The Photogrammetric Record》1995,15(86):205-216
The use of digital imagery, acquired through charge-coupled devices (CCDs) either by the scanning of hard copy film or direct capture through the use of a CCD camera, has fundamentally changed the photogrammetric environment. In order to fully exploit these digital image data, the photogrammetrist must employ system design, implementation philosophies and processing methodologies different from those of traditional film based photogrammetry. It is now possible for these new photogrammetric systems to be operated from low cost, high performance PC and Macintosh class commercial hardware, using vendor supplied software for user developed applications. This paper explores lessons learned and experiences gained from low cost, digital photogrammetric system development and CCD image exploitation. Examples and discussion presented in this paper include: (1) integration of user developed applications with commercial hardware and software; (2) user interface design; (3) validation of processing algorithms within the digital image domain; (4) system calibration; (5) digital image data handling, management and storage; and (6) image data compression. The film based photogrammetric system provides the point of departure to digital photogrammetry. Technical knowledge, system design and implementation and CCD image exploitation provide the experience. 相似文献
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Modelling and representation issues in automated feature extraction from aerial and satellite images
《ISPRS Journal of Photogrammetry and Remote Sensing》2000,55(1):34-47
New digital systems for the processing of photogrammetric and remote sensing images have led to new approaches to information extraction for mapping and Geographic Information System (GIS) applications, with the expectation that data can become more readily available at a lower cost and with greater currency. Demands for mapping and GIS data are increasing as well for environmental assessment and monitoring. Hence, researchers from the fields of photogrammetry and remote sensing, as well as computer vision and artificial intelligence, are bringing together their particular skills for automating these tasks of information extraction. The paper will review some of the approaches used in knowledge representation and modelling for machine vision, and give examples of their applications in research for image understanding of aerial and satellite imagery. 相似文献
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以武汉市为研究对象,基于武汉多时相航摄影像数据,借助GIS技术和空间分析方法,以城市用地扩展速度和强度指数、分形维数、紧凑度为城市形态指标,实证分析1986～2008年间武汉城市建成区外部形状的变化过程,期望为武汉规划决策的制定以及相关调控措施的研究等提供依据。 相似文献
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《制图学和地理信息科学》2013,40(3):261-282
A great convergence of cartography, secrecy, and power occurred during the Cold War. In the American case, a complex series of interactions between secret and classified programs and institutions and their publicly accessible counterparts accomplished both traditional and novel objectives of military geographic intelligence. This process also yielded the World Geodetic System, a mass-centered "figure of the earth" at accuracies adequate for warfare with intercontinental ballistic missiles. A structural and institutional separation developed between enterprises charged with overhead data acquisition systems, which were classified at increasingly high levels of secrecy, and those responsible for data reduction, analysis, and mapping systems, which remained largely unclassified and publicly accessible, in part to conceal the classified data acquisition systems. This structural separation destabilized photogrammetric mapping by displacing systems that privileged dimensional stability with systems that privileged novel sensor types more appropriate to Cold War geo-political objectives and constraints. Eventually, photogrammetric mapping systems were re-stabilized by successfully implementing analytical solutions imposed in digital mapping and data management systems. This achievement re-privileged dimensional stability, now redefined to the new media of geo-referenced digital data. In the early 1970s these developments culminated in advanced research projects of Military Geographic Intelligence Systems (MGIS). Their deployment in the Vietnam War was both their apex and their undoing. In the aftermath, classified mapping and database systems diverged from civilian versions of MGIS, which became known as Geographic Information Systems (GIS). 相似文献
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O. Altan G. Toz S. Kulur D. Seker S. Volz D. Fritsch M. Sester 《ISPRS Journal of Photogrammetry and Remote Sensing》2001,55(5-6)
After a catastrophe like an earthquake, one on the most important problems is to provide shelter and housing for the homeless. To this end, it is necessary to decide if a building is still habitable, or if it is has to be renovated or even torn down. A prerequisite for such decisions is the detailed knowledge about the status of the building. Earlier earthquakes revealed problems in the processes of documenting and analysing the building damage, as they demanded much effort in terms of time and manpower. The main difficulties appeared to be because of the analogue damage assessments which created a great variety of unstructured information that had to be put in a line to allow further analysis. Apart from that, documentation of damage effects was not detailed and could only be carried out on the spot of a disaster. The aim of this study is to make an improvement, using combination of Geographic Information Systems (GIS) as a management and data analysis tool and photogrammetry as a documentation method. Photogrammetric data acquisition is achieved using a CCD camera and the digital photogrammetric software package PICTRAN by Technet. The information system part is the GIS package ArcView by ESRI. The combination of rapid data acquisition and GIS offers a quick assessment of the situation and the possibility of its objective and holistic analysis. This is the prerequisite for a quick initiation of appropriate measures to help people. 相似文献
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地理信息系统在资源环境评价与管理中的应用 总被引：1，自引：0，他引：1
介绍了地理信息系统在资源环境评价与管理中的具体功能,讨论了GIS,RS,GPS在资源环境特别是水资源和精准农业管理上的应用,并指出地理信息系统作为一种信息处理工具能满足数字信息获取的三个阶段:数据的收集、数据的分析、数据的转换和信息处理。 相似文献
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Stephen Wise 《Transactions in GIS》2002,6(3):327-337
Data capture from paper maps remain a slow and costly part of many Geographic Information System projects. In this paper a simple method is described which makes use of the facilities of desktop graphics software to capture raster data from scanned thematic maps. The first stage is to use the flood fill tool to identify the regions of the map that represent the data values and set them to a separate colour for each thematic category. This edited image is then imported into a GIS, where a specially written majority filter is used to classify any remaining pixels to produce a raster GIS layer. The technique is tested on samples from three maps, giving accuracy levels of over 90% in all cases when compared with digitising the same maps by hand. The technique could be useful for situations where a rapid and simple means of data capture is needed and could be developed further by drawing on techniques for contextual classification rather than relying on a general purpose flood fill algorithm. 相似文献
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航测大比例尺数字化测图中的若干问题 总被引：1，自引：1，他引：1
在航测全数字化测图软件还比较昂贵的情况下，立足现有高备，运用测绘新技术，进行大比例尺航测数字化成因，获取数字地图，为城市地理信息系统提供基础信息，对中小城市的测绘工作是一种较好的选择。 相似文献
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结合地图数字化为ＧＩＳ采集空间数据的工作实际，对直角、直线数字化的数据处理的平差模型以及相应的精度评定方法进行了研究。作者认为，通过平差和评定精度，可以提高数字化的精度，并有助于实现对ＧＩＳ数据采集的质量控制 相似文献
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应用Arc/Info建立湖北省区域稳定性评价空间数据库 总被引：1，自引：0，他引：1
以Arc/Info为基本工具,以遥感信息为获取、更新数据库数据的主要信息源,结合前人地学资料,建立了湖北省区域稳定性评价空间数据库,阐述了该空间数据库的内容、功能、应用和意义. 相似文献
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地理信息系统是智慧城市建设中的重点项目。地理信息是大部分智慧城市应用系统的基础信息。倾斜摄影测量技术的发展,使得获取三维地理信息的成本大大降低,数据应用更加广泛。地理信息实时共享是开拓智慧城市应用领域的关键。因此,如何部署数据、计算、软件和软件模块资源,如何建设地理信息服务平台,对各种应用开发会产生重大影响。各种资源在网络中的部署、信息服务"供给侧"设计、网络业务的高效无缝集成,是对智慧城市设计者的新挑战。 相似文献
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Hard and Soft Skills in Preparing GIS Professionals: Comparing Perceptions of Employers and Educators 
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下载免费PDF全文 Organizations that hire GIS professionals look for entry‐level employees with specialized technical skills but also other competencies such as effective communication and a capacity to think critically and creatively. Indeed, the success of GIS projects and initiatives often depends on individuals who possess a combination of specialized GIS skills and more general competencies that influence their ability to collaborate and manage resources. This article presents findings from a survey of GIS employers and educators concerning the importance of hard and soft skills among entry‐level GIS professionals. A key finding is the high level of consistency in ratings assigned by employers and educators concerning hard skills such as data editing and GIS analysis and soft skills including problem solving and adaptability. However, the groups were less similar in ratings assigned to data capture skills, project management, and written/verbal skills. GIS qualifications were also compared, revealing a greater emphasis on internships among educators and higher ratings assigned to academic GIS certificates among employers. 相似文献
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Matt Duckham 《Transactions in GIS》2002,6(2):179-193
The current lack of error-sensitive functionality found in commercial GIS is at odds with the research focus error-sensitive GIS development has enjoyed over recent years. In an attempt to address this undesirable situation, this paper explores the development of error handling capabilities within GIS from the perspective of GIS users. Increasingly, GIS users need to fulfil a variety of different roles, from database designers and data capture personnel through to decision makers, each of which may require an awareness of data quality issues. The user-oriented approach taken here contrasts with the predominately developer-oriented perspective in the literature. The paper concludes that from a user's perspective it is possible to identify a number of simple reformulations of current research that would help bring about the desired increase in availability and use of error-sensitive functionality within commercial GIS technology and applications. 相似文献
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随着无人机航空摄影的不断发展和成熟,利用无人机航摄制作高分辨率数字正射影像图在测绘生产中应用日益广泛。但在城市区域制作大比例尺正射影像图时存在建筑物倾斜、遮挡严重、不能和GIS矢量数据进行很好套合等问题,而数字真正射影像图能很好地解决这些问题。本文基于INPHO软件对城市无人机航摄影像进行真正射影像制作,总结出无人机航摄影像制作真正射影像的作业流程和需要注意的关键问题。 相似文献
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对三维地理场景真实还原是数字孪生的核心技术要求之一,地理信息系统与游戏引擎的结合为城市实景三维建设提供了新思路。倾斜摄影数据是实景三维建设中重要的数字底板要素,针对游戏引擎加载倾斜摄影数据问题,以Unreal Engine 4渲染为例提出一种倾斜摄影三维模型数据转换方法。该方法利用原始数据的文件组织,通过数据解析获取转换信息构建数据读取树;迭代树节点时分别对几何数据与纹理数据进行转换,转换过程兼顾游戏引擎渲染资源所需物理属性,最终完成几何和纹理重组。将该方法应用于深圳市福田区倾斜摄影数据,实验结果表明,所提方法能准确实现倾斜摄影三维模型数据至Unreal Engine 4渲染资源的转换,可为类似三维模型数据转换问题提供理论与技术参考。 相似文献
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基于三级客户机／服务器模式的GIS软件平台设计与实现 总被引：13，自引：0，他引：13
Internet/Intranet的快速发展、数据仓库技术的应用，使得GIS空间数据管理与应用呈现多用户、分布式和网络化的特点。面对这一发展趋势，传统GIS软件平台普遍采取的单机或二级客户机／服务器模式存在难以克服的缺陷，开发基于三级客户机／服务器模式的GIS软件平台成为当前研究的重要课题。本文详细介绍了基于三级客户机／服务器模式GIS软件平台的基本设计思路和体系结构，并且在此基础上，运用socket技术构造中间件，建立了一个试验性平台－VirtualWorld，同时介绍了此体系上解决GIS互操作方案，最后对试验进行了简单分析。 相似文献
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Johannes F. Kruiger Vedran Kasalica Rogier Meerlo Anna‐Lena Lamprecht Enkhbold Nyamsuren Simon Scheider 《Transactions in GIS》2021,25(1):424-449
Loose programming enables analysts to program with concepts instead of procedural code. Data transformations are left underspecified, leaving out procedural details and exploiting knowledge about the applicability of functions to data types. To synthesize workflows of high quality for a geo‐analytical task, the semantic type system needs to reflect knowledge of geographic information systems (GIS) at a level that is deep enough to capture geo‐analytical concepts and intentions, yet shallow enough to generalize over GIS implementations. Recently, core concepts of spatial information and related geo‐analytical concepts were proposed as a way to add the required abstraction level to current geodata models. The core concept data types (CCD) ontology is a semantic type system that can be used to constrain GIS functions for workflow synthesis. However, to date, it is unknown what gain in precision and workflow quality can be expected. In this article we synthesize workflows by annotating GIS tools with these types, specifying a range of common analytical tasks taken from an urban livability scenario. We measure the quality of automatically synthesized workflows against a benchmark generated from common data types. Results show that CCD concepts significantly improve the precision of workflow synthesis. 相似文献
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This paper discusses the use of near vertical aerial photographs archived onto Kodak Photo CD in the production of a digital elevation model of the Isle of May, Scotland. Control for the survey was obtained using differential GPS receivers and the photogrammetric processing was carried out using low cost PC hardware and software. The elevation model is being used in a GIS to enable the spatial analysis of the island's seal population. 相似文献