共查询到20条相似文献，搜索用时 46 毫秒
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数字高程模型（DEM）精度评估 总被引：5，自引：0，他引：5
虽然许多研究者对DEM误差有着不同的观点，但是DEM的质量控制和精度评估已经是当前GIS工作者非常关注的问题。本文在总结前人研究成果的基础上，论述了精度评估的主要研究内容；影响DEM精度的主要因素；误差的不同分类体系；精度评估的理论和方法；精度评估的模型。提出了基于分形分析的DEM精度评估的新思路。 相似文献
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Landsat7 ETM＋影像的融合和自动分类研究 总被引：25，自引：0，他引：25
利用SFIM、MLT、HPF和修改的Brovey(MB)等遥感影像融合算法对Landsat 7 ETM 影像进行融合和自动分类研究，并就融合影像的光谱保真度、高频空间信息融人度和分类精度对这些方法进行评价。结果表明SFIM变换几乎完全保持了原始影像的光谱特点，并具有最高的平均分类精度；MB变换具有最高的高频空间信息融人度；MLT变换也具有较高的分类精度；只有HPF变换的各项指标都不突出。所有4种融合影像的分类精度都较原始影像的分类精度有明显的提高。这表明，源于同一传感器系统的不同分辨率影像的融合可以避免异源传感器融合影像所常见的各种参数、时相和配准误差，所以能够明显地提高影像的自动分类精度。 相似文献
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高维遥感图像的快速分类算法 总被引：1，自引：0，他引：1
为了实现对高维遥感图像的快速准确分类,提出了一种基于k均值二叉树支持向量机(SVM)的分类方法。该方法通过对选取的训练样本进行k均值聚类,生成支持向量机分类二叉树,作为确定最佳分类顺序的依据,以降低分类过程中的误差累积并提高整体分类精度,而且可缓解由样本数量不均衡导致的分类误差。该方法可在不进行降维处理的情况下,对高维遥感图像进行快速准确分类。测试结果表明,其分类速度和分类精度都优于传统的支持向量机分类结果。 相似文献
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填挖方量计算的精度评定 总被引：2，自引：0，他引：2
指出填挖方量计算的主要误差来源是DEM误差，分析了DEM的产生过程，对DEM误差来源作了分类讨论，最后提出一种比较合理，快速的精度评定方法。 相似文献
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硬分类对低空间分辨率图像分类效果的影响 总被引：1，自引：0，他引：1
针对图像分类效果与图像的空间分辨率之间的关系尚未得到定量分析的问题,该文以中巴卫星CCD图像对冬小麦的分类结果为参考数据,对空间分辨率与制图精度之间的关系进行理论分析。通过在不同空间分辨率状态下分别计算随着硬分类阈值的取值变化而得到的由漏分误差和错分误差所形成的"帕累托边界",来分析硬分类器所能达到的分类精度的极限。结果表明,在空间分辨率相对较低的前提下,图像整体分类效果取决于被分类像元的纯度在图像中的数量分布状况。研究结论可为制作遥感专题图时如何选取合适的空间分辨率图像提供参考。 相似文献
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红柳林矿三井贯通测量 总被引：1，自引：0，他引：1
通过全站仪和陀螺仪等测量仪器在贯通测量中的广泛应用,对各项误差指标进行分析,可以发现在现代矿山测量中广泛使用先进仪器设备,对于保证成果的精度及降低矿山测量人员劳动强度起着非常重要的作用。通过贯通实际误差和理论预计误差对比得出结论并具有一定的参考价值。 相似文献
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对改善城市GIS空间数据几何精度方法的探讨 总被引：2，自引：0，他引：2
用数字化仪对已测地图进行数字化时，产生的误差必将降低城市ＧＩＳ空间数据的几何精度。作者结合自己的工作实践，分析了数字化误差的类型和来源，并根据广义平差理论推导出一组适宜的平差模型，从而对改善其精度的方法进行探讨。 相似文献
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在港口工程测量中，目前对斜桩定位的精度分析与估算方法论述较少，本文就控制斜桩平面扭角、竖角误差对桩位影响以及就位对桩位精度的影响等进行了理论的探讨和估算。 相似文献
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黎建平 《测绘与空间地理信息》2018,(9)
通过对原始点云数据精度和点云数据分类误差的研究,抽检不同地表、不同植被覆盖密度、不同植被高度点云分类的数据,分析其对LiDAR的DEM成果精度的影响,对LiDAR数据DEM成果的质量检验与精度评定具有参考价值。 相似文献
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《测量评论》2013,45(18):241-242
AbstractIn working out vertical heights on the Akuse-Kete Krachi chain of triangulation in the Gold Coast a fairly considerable difference was found between values of the coefficient of refraction obtained from observations taken during the day and those taken at night, the mean values being 0.069 for daylight observations to heliographs and 0.087 for night observations to lamps. This difference no doubt is due mainly to the condition of the atmosphere during the day differing from its condition during the night rather than to any effect due to different sources of light. A new chain has recently been observed in Western Ashanti, and the index of refraction for the daylight observations again gave a lower value than that obtained from the night observations, the figures being 0.073 and 0.099 respectively. For the night work three different sources of light were used, hurricane lamps for short lines, Tilley vapour-pressure lamps for lines of intermediate length, and McCaw acetylene signalling lamps by Watts for long lines. It occurred, therefore, to the writer to examine the results to see if the mean values of the index of refraction showed any variations for the different light sources, since it seemed reasonable to suppose that the constitution of the light emitted from each source would be different and hence that the coefficient of refraction might vary. 相似文献
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A. A. Lyutyy 《地理信息系统科学与遥感》2013,50(2):127-139
The author continues development of his concept of cartography as the “language of the map,” an earlier paper of this subject appearing in translation in M.S.R.S., 1985, No. 1. Although the term language has been widely used to describe cartographic communication, current theory fails to incorporate aspects of the language which provide for a comprehensive understanding of its structure and function. In particular, the language of the map and its symbolic elements cannot be explained reflexively by methods and rules of symbol and map design, since these elements were developed not before but after the existence of the language. The language of the map thus is proposed as the mechanism which provides for replicability or duplication in the way a system of mapmaking-map use functions (under diverse conditions, purposes, historical periods, and levels of training of users) through its different methods, models, and norms. Translated from: Geografiya i prirodnyye resursy, 1985, No. 3, pp. 142-151. 相似文献
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M. J. Miles 《The Photogrammetric Record》1968,6(32):196-201
The theory of the solution of the stereogram is developed from the condition that the vector triangle, formed by the base-line and the two rays from the perspective centre to a common model point, shall be in equilibrium. Using this approach the unique definition of a point in the model follows naturally from the solution of the relative orientation problem. 相似文献
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《测量评论》2013,45(91):206-210
AbstractThe observations to height Kilimanjaro were made from two ground stations, Domberg (5,081·6 ft.) and Lelatema (5,323.1 ft.) and from a point called Kibo near Kaiser Wilhelm Spitze which is regarded as the highest point on the crater rim. It was originally intended to include a third ground station, Kifaru, but it was discovered that the ice cap obstructed observations between this point and the top. 相似文献
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利用卫星测高资料推求西北太平洋海域的海洋大地水准面 总被引：3，自引：0，他引：3
本文根据卫星测高数据和海面动力地形资料，绘制了不相上下北太平洋海域局部大地水准面的精细结构图，对解决卫星测高技术中大地水准面积和海面地形的可分性问题作了初步尝试。 相似文献
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《测量评论》2013,45(37):429-436
AbstractGauss's method of collimation is usually given scant attention in survey text-books. The following notes are based on experiments carried out at Accra in making a collimation base, the collimator being a Watts 2I-inch self-adjusting level fitted with a parallelplate micrometer. 相似文献
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《测量评论》2013,45(3):131-133
AbstractUp to 31st March 1922, the work in Ireland with regard to the revision and supply of Ordnance Survey Maps was governed by similar rules to those existing at the Ordnance Survey of Great Britain. No changes were made in the Irish Free State until the revision of Co. Waterford was completed on the 25-inch scale in 1923. It was then decided to depart from the usual procedure of taking up the work of the revision of Counties according to a cycle of years, and to revise those particular portions of the country in which extensive alterations had been carried out by reason of the division of properties by the Congested Districts Board and the Irish Land Commission. Accordingly, those portions of Counties Galway, Mayo and Roscommon which had undergone the greatest development were taken up for revision. In all eighty-nine sheets were specially revised and completed by 1928. 相似文献
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《测量评论》2013,45(23):16-20
AbstractThis paper is written primarily with the object of ascertaining how other Colonies and Dominions deal. with the adjustment of their trigonometricallevels; further, since the greater part of Nigeria is now covered by a framework of levels of primary accuracy it is of interest to examine the results. Moreover, the evaluation of the coefficient of refraction, and from it the temperature lapse-rate, is of some importance in view of the recent publication of the War Office Aneroid Tables. These tables are based on a standard lapse-rate of temperature. 相似文献