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地理信息是国家基础信息资源,其获取方式与服务方式与相关学科技术的发展水平相适应。研究地理信息获取和服务方式的发展变化过程和互联网大数据时代地理信息获取和服务的新方式,为地理信息发展和服务提供有益的参考。大数据时代,用户使用地理信息的行为会成为地理信息服务依赖的重要数据,可以从中分析获取大至人类群体活动规律、小至用户行为习惯偏好等信息。此外,在这个阶段,大众不仅是地理信息服务的使用者,同时也是地理信息的采集者、提供者。 相似文献
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志愿者地理信息数据大都依靠志愿者上传,数据质量未知,阻碍了志愿者地理信息的广泛应用,因此是志愿者地理信息首要解决的问题。本文分析了影响志愿者地理信息质量的相关因素和基于参考数据评价方法的相关研究成果,在此基础上提出了一种基于参考数据的志愿者地理信息质量评价方法,以最常见的数据完整性和数据精度作为质量评价的质量元素,详细论述了这两种质量元素的内涵。针对数据完整性评价,提出了与匹配相结合的几何数据完整性度量方法和基于属性项饱和度的属性数据完整性度量方法;针对几何数据精度评价,提出了基于变缓冲区的度量方法。然后给出了该评价方法的一般流程。最后,以深圳市Open Street Map数据为例,选取最新导航数据作为参考数据进行试验验证。实验结果表明,深圳市Open Street Map数据点要素完整性较差,但是线要素完整性与精度都非常高,可以作为基础地理信息的更新数据源。 相似文献
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大比例尺地理信息数据由于详尽的数据内容和精准的位置信息,在城市经济社会发展中发挥着重要作用。然而由于传统的服务方式的限制,数据的使用效率并不高。地理空间框架数据结合GIS技术和网络技术,将大比例尺地理信息数据使用方式从线下转到线上,提高了数据使用效率。而本文提出的主动式地理信息服务模式是一种全新的地理信息服务模式,将大比例尺地理信息服务数据与用户业务数据深度融合,最大限度地满足用户的业务需求,将是地理信息服务模式未来的发展方向。 相似文献
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基础地理信息数据库的数据质量控制探讨 总被引:2,自引:0,他引:2
基础地理信息数据对基础地理信息数据库来说至关重要。数据质量的好坏是基础地理信息数据库建设成败的关键。本文结合新疆1∶10000基础地理信息数据库、国家1∶50000地形要素数据缩编更新项目——新疆区域的实施实践,对省级基础地理信息数据库建库过程中数据质量控制进行了探讨。 相似文献
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地理信息志愿者信誉度评估的版本相似度模型——以面目标为例 总被引:1,自引:0,他引:1
针对自发地理信息中存在大量恶意、虚假、低质量数据,提出了一种基于版本相似度的VGI志愿者信誉度计算模型。该模型将每个志愿者对某个地理空间目标的一次编辑结果定义为一个版本,当其他用户编辑该目标版本时,通过计算版本相似度来获得其他用户对该志愿者这个目标版本的支持度;然后通过计算其他贡献者对某志愿者所贡献的每个目标的支持度,对所有目标的支持度进行加权平均获得该志愿者的综合信誉度。其中版本相似度综合目标空间和属性相似性的主要因素进行加权计算。然后以面目标为例阐述了本文志愿者信誉度计算过程。为了验证本文信誉度计算模型的合理性,笔者采用德国柏林OpenStreetMap数据进行试验,试验表明通过本文模型计算获得的用户信誉度与其贡献的要素质量总体上正相关。 相似文献
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通过分析地理信息数据生产中的数据质量和空间数据基础设施的数据质量内容和特性,基于数字南极地理信息公共服务平台建设中的数据内容,讨论了在地理信息数据生产和地理信息公共服务平台建设中质量控制和元数据制作工作的重要性,并以保证数字南极地理信息公共服务平台建设的数据质量为目标提出了数据质量元素和评价方法,最后就进一步提高平台数据质量提出了建议。 相似文献
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针对GIS数据与计算机辅助设计(CAD)数据之间的差异性,以及现有转换方法存在的问题,该文提出了一种计算机辅助设计数据处理方法——采用空间数据操作引擎(FME)和Arc Map联合使用的方法。该方法能够较好地解决计算机辅助设计数据向GIS数据转换的难题,实现了对计算机辅助设计数据的批量转换和处理。以某市的地形图为数据源进行实例论证,实验结果显示运用该文所提方法能够更好地处理计算机辅助设计数据,为计算机辅助设计地形图的转换提供了可行的方案;特别是对转换出来的数据进行了拓扑重建、附属性值以及多边形数据分类处理,能够更好地保持数据的精度和完整性,更有利于数据的入库。 相似文献
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3D GISs were developed simultaneously in the late 1980s in a number of different disciplines.The development of these 3D GISs can not yet meet all needs for new representations and analytical tools in 3D envir onments.In this paper,the data structures,especially solid-based data representa tions are introduced.Then,a typical object-oriented data model is put forth to show a new data model.And at last,two data access methods are proposed to make the data model clear. 相似文献
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Aggregation may be used as a means of enhancing remotely sensed data accuracy, but there is a tradeoff between loss of information and gain in accuracy. Thus, the choice of the proper cell size for aggregation is important. This letter explores the change in data accuracy that accompanies aggregation and finds an increase in image thematic accuracy with increasing cell size, resulting from 1) reduction in the impact of misregistration on thematic error and 2) mutual cancelation of inverse classification errors occurring within the same cell. A model is developed to quantify these phenomena. The model is exemplified using a vegetation map derived from an aerial photo. The model revealed a major reduction in effective location error for cell sizes in the range of 3-10 times the size of mean location error; reduction in effective classification error was minor. 相似文献
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WUXiaofang CAIZhongliang WUGuofeng DUQingyun 《地球空间信息科学学报》2003,6(4):27-31
Through analyzing the principle of data sharing in the database system, this paper discusses the principle and method for integrating and sharing GIS data by data engine, introduces a way to achieve the high integration and sharing of GIS data on the basis of VCT in VC , and provides the method for uniting VCT into RDBMS in order to implement a spatial database with object-oriented data model. 相似文献
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T. Ch. Malleswara Rao L. Venkataratnam K. R. Rao 《Journal of the Indian Society of Remote Sensing》1980,8(2):27-32
Contrast enhancement, one of the image processing techiques, is developed on the Multispectral Data Analysis System (MDAS) for enhancing the LANDSAT data. The purpose of image processing for enhancement is to improve the obscure objects data in the image to stand out more readily for good sensing to the human eye. It is observed on MDAS that some of the LANDSAT scenes when examined on the color display, give inadequate information for the required objective of interpretation. This is due to poor tonal contrast in the scene because of prevailing climatological conditions at the time of satellite pass over that area. Also, the LANDSAT data usually occupy a small subset of the total brightness range 0–127. To provide optimal contrast and variation for color compositing, contrast enhancement may by performed on the data before going to trie information processing (categolization) on the landsat scene. This paper describes the algorithms of parametric linear and non linear contrast enhancement techniques. A typical example to differentiate the degree of salinity in the soils was tested with the suggested algorithms and the results are tabulated in the form of photographs. The test area is selected from Haryana (frame no. 158-040 dated 2nd May, 1977) for testing the algorithms. The enhancement software developed on the MDAS stretches all the four Landsat bands and generates an output tape with the format similar to LANDSAT computer compatible tape (CCT). The stretched results of 5 and 7 bands are displayed in this paper. A false color composite which appears as on the color displya could also be generated from 4, 5 and 7 bands. The enhanced output was found to be useful for easily categorizing the data into various categories on MDAS. 相似文献
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Parametric least squares collocation was used in order to study the detection of systematic errors of satellite gradiometer
data. For this purpose, simulated data sets with a priori known systematic errors were produced using ground gravity data
in the very smooth gravity field of the Canadian plains. Experiments carried out at different satellite altitudes showed that
the recovery of bias parameters from the gradiometer “measurements” is possible with high accuracy, especially in the case
of crossing tracks. The mean value of the differences (original minus estimated bias parameters) was relatively large compared
to the standard deviation of the corresponding second-order derivative component at the corresponding height. This mean value
almost vanished when gravity data at ground level were combined with the second-order derivative data set at satellite altitude.
In the case of simultaneous estimation of bias and tilt parameters from ∂2
T/∂z
2“measurements”, the recovery of both parameters agreed very well with the collocation error estimation.
Received: 10 October 1996 / Accepted 25 May 1998 相似文献