共查询到20条相似文献，搜索用时 93 毫秒
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地图投影作为地图学的重要组成部分和建立地图的数学基础,其投影的选择至关重要,本文通过研究和探讨地图投影理论,并结合本人工作实际中曾遇到的有关投影问题,浅析地图投影的数学基础和地图投影的选择与应用中应注意的技术问题,以求为国民经济建设提供更为准确、优质的测绘服务保障。 相似文献
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《中国地理与资源文摘》2006,(1)
P2082006010873一种新的球面三角投影:等角比投影(EARP)=A new pro-jection for spherical triangle:equal angle ratio projection(EARP)/袁文,马蔼乃…∥测绘学报.—2005,34(1).—78~84设计一种面向球面三角形的新投影———等角比投影(Equal Angle Ratio Projection,EARP),该投影包括平行以及同轴两种模式,支持正六面体、正八面体、正二十面体等柏拉图立体(Plato Polyhedron)以及任意Voronoi球面三角剖分.可以选择任意形状的投影平面三角,投影坐标由球面弧角度与特征球面弧角度之比决定,弧线族上的均分点与2维投影面上均匀分布… 相似文献
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科右中旗电厂测量工程作业的技术设计应用全球定位系统（简称GPS）,选择坐标系统、投影带、投影面,合理地利用和配置已知点,使控制网的精度满足了多种比例尺测量图的需要。 相似文献
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自然地理界线判别的投影寻踪技术 总被引：1，自引：0，他引：1
改进投影寻踪技术是一种基于改进单纯形法直接优化投影寻踪技术的投影函数和投影方向的一种新方法,提出应用改进投影寻踪技术建立自然地理界限划分的判别模型,利用该模型可把自然地理上各气象站点的多维分类指标综合成一维投影值,根据投影值的大小可对气象站点样本集进行合理判别,从而科学确定自然地理的气候带.以福建省南亚、中亚热带自然地理划分为例,探讨了应用改进投影寻踪技术在自然地理划分中的具体应用,福建中、南亚热带自然地理划分结果表明,直接由样本数据驱动的改进的投影寻踪自然地理界线判别模型用于中、南亚热带自然地理的划分简单可行,具有较强的适用性和应用性,可操作性强,可广泛应用于各气候带及地域界线的划分. 相似文献
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Bojan Šavrič Bernhard Jenny 《International journal of geographical information science》2014,28(12):2373-2389
The recently introduced adaptive composite map projection technique changes the projection to the geographic area shown on a map. It is meant as a replacement for the commonly used web Mercator projection, which grossly distorts areas when representing the entire world. The original equal-area version of the adaptive composite map projection technique uses the Lambert azimuthal projection for regional maps and three alternative projections for world maps. Adaptive composite map projections can include a variety of other equal-area projections when the transformation between the Lambert azimuthal and the world projections uses Wagner’s method. To select the most suitable pseudocylindrical projection, the distortion characteristics of a pseudocylindrical projection family are analyzed, and a user study among experts in the area of map projections is carried out. Based on the results of the distortion analysis and the user study, a new pseudocylindrical projection is recommended for extending adaptive composite map projections. The new projection is equal-area throughout the transformation to the Lambert azimuthal projection and has better distortion characteristics then small-scale projections currently included in the adaptive composite map projection technique. 相似文献
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针对多种地图投影间自由变换的需求 ,综合对比地图投影变换的主要方法及其特点 ,该文认为反解变换是解决多种投影间投影变换的最佳途径。以此为基础 ,具体探讨了地图投影变换计算机实现的主要过程 ,讨论了地图投影体系、投影参数、算法优化和误差控制等投影变换计算机实现中的关键问题 相似文献
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地缘政治理论的提出和发展深刻烙印了地图的影响。在地缘政治发展史中,不同地图投影既服务于各思想家的理论提出,也深入到各思想家在不同时期对自身理论的动态修正。地图投影到底是如何参与到地缘政治理论构建过程中的?本文在既有地缘政治地图研究的基础上,从空间性和文本性两大地图基本属性出发,通过阐释并沟通地图的空间分析与话语分析功能,探讨地图投影与地缘政治理论构建间的关系。一方面,地图投影变形抽象后的心象地图框架为构建地缘政治理论提供了空间依托;另一方面,地图投影通过地图变形在复杂情境中聚集了丰富的文本性含义。在地图投影各层次文本性的互文（互补性叙事）下,新的地图话语得以产生并渗透进心象地图,具象式推动了地缘政治理论核心概念的生成和逻辑关系的构建。综合考虑麦金德的地图观影响,本文对麦金德“心脏地带”地缘政治思想变迁各阶段（1904年、1919年、1943年）地图投影透视的分析验证了该关系框架的解释力。这启示该分析框架在其他地缘政治理论研究中的潜在适用性,更期待在百年变局和复兴全局等交织下的复杂情境中,基于地图投影创新互文下的中国地缘政治理论构建。 相似文献
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Bojan Šavrič Tom Patterson 《International journal of geographical information science》2019,33(3):454-465
The Equal Earth map projection is a new equal-area pseudocylindrical projection for world maps. It is inspired by the widely used Robinson projection, but unlike the Robinson projection, retains the relative size of areas. The projection equations are simple to implement and fast to evaluate. Continental outlines are shown in a visually pleasing and balanced way. 相似文献
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Bernhard Jenny Bojan Šavrič Tom Patterson 《International journal of geographical information science》2013,27(6):935-952
There are two problems with current cylindrical projections for world maps. First, existing cylindrical map projections have a static height-to-width aspect ratio and do not automatically adjust their aspect ratio in order to optimally use available canvas space. Second, many of the commonly used cylindrical compromise projections show areas and shapes at higher latitudes with considerable distortion. This article introduces a new compromise cylindrical map projection that adjusts the distribution of parallels to the aspect ratio of a canvas. The goal of designing this projection was to show land masses at central latitudes with a visually balanced appearance similar to how they appear on a globe. The projection was constructed using a visual design procedure where a series of graphically optimized projections was defined for a select number of aspect ratios. The visually designed projections were approximated by polynomial expressions that define a cylindrical projection for any height-to-width ratio between 0.3:1 and 1:1. The resulting equations for converting spherical to Cartesian coordinates require a small number of coefficients and are fast to execute. The presented aspect-adaptive cylindrical projection is well suited for digital maps embedded in web pages with responsive web design, as well as GIS applications where the size of the map canvas is unknown a priori. We highlight the projection with a height-to-width ratio of 0.6:1, which we call the Compact Miller projection because it is inspired by the Miller Cylindrical projection. Unlike the Miller Cylindrical projection, the Compact Miller projection has a smaller height-to-width ratio and shows the world with less areal distortion at higher latitudes. A user study with 448 participants verified that the Compact Miller – together with the Plate Carrée projection – is the most preferred cylindrical compromise projection. 相似文献
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Bernhard Jenny Tom Patterson Lorenz Hurni 《International journal of geographical information science》2013,27(11):1687-1702
The design of new map projections has up until now required mathematical and cartographic expertise that has limited this activity to a small group of specialists. This article introduces the background mathematics for a software-based method that enables cartographers to easily design new small-scale world map projections. The software is usable even by those without mathematical expertise. A new projection is designed interactively in an iterative process that allows the designer to graphically and numerically assess the graticule, the representation of the continents, and the distortion properties of the new projection. The method has been implemented in Flex Projector, a free and open-source application enabling users to quickly create new map projections and modify existing projections. We also introduce new tools that help evaluate the distortion properties of projections, namely a configurable acceptance index to assess areal and angular distortion, a derived acceptance visualization, and interactive profiles through the distortion space of a projection. To illustrate the proposed method, a new projection, the Cropped Ginzburg VIII projection, is presented. 相似文献
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Ibrahim Oztug Bildirici 《International journal of geographical information science》2013,27(12):2295-2309
Tissot’s indicatrix or ellipse of distortion is a diagram that is the projection of an infinitesimal circle on the original surface. It is normally an ellipse of which elongation depends on the amount of distortion caused by map projection. It provides a medium for analyzing existing projections and developing new ones. The ellipse can be scaled and depicted on the map for visualization purposes. This paper presents an alternative approach, in which the projection of a finite small circle on the sphere is used. Its projection is normally an ellipse that can be very close to Tissot’s indicatrix, and is called quasi indicatrix, here. Its parameters can be derived from the forward projection equations without using partial derivatives. Therefore, it is a useful and practical approach from a programmer’s point of view. The quasi indicatrix approach is also numerically tested on Aitoff–Hammer projection with a set of points. The indicatrix parameters obtained by using this approach deviate 0.5% from the ground truths at most, being the average less than 0.2%. 相似文献
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南大洋海冰分布是南极考察过程中影响破冰船航行的重要因素,也是南极研究的重要内容之一。目前国际上不同机构发布的南大洋海冰分布图,大多是球面投影,不能直接用于主流的瓦片地图发布。将极方位立体投影海冰图转换为目前主流的网络墨卡托投影地图,并利用合适的图像重采样方法,按照不同级别比例尺进行瓦片切割和编号存储,最终实现海冰影像地图的发布共享是本文的主要研究内容。笔者对不同的图像重采样方法进行了比较,分析了最邻近点采样方法、双线性内插和双三次卷积重采样方法的优劣,针对本文的研究优选双线性内插方法进行影像地图瓦片的切割,并最终叠加融合在Google地图上,实现了Google底图、准实时海冰影像图与破冰船走航位置的集成显示,为雪龙船的冰区航行提供了重要的数据支撑。 相似文献
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Despite incontrovertible scientific evidence to support a round Earth, GIS software implementation typically models the Earth with flat map projections. This choice has consequences that vary from mild to severe. This paper explores solutions that range from moderate measures to correct for map projection errors to radical revisions of standard practice that place all calculations on the ellipsoid. On examination, the best practice requires a distinct projection choice for each geometric operation. Multiple reasons, from the technical to ethical, justify revised practices and increased vigilance for the errors induced by inappropriate projections. 相似文献