DLG空间要素网格综合法研究     

白建荣  于洪伟 《测绘与空间地理信息》2008,31(1):74-78

通过将网格法用于DLG空间要素综合的数学计算过程的研究,提出DLG要素综合的一种新方法——网格综合法。通过对点、线、面要素网格综合法的系统分析,重点论述线、面典型空间要素的网格综合法的理论和方法,并提出数学模型,为空间要素自动地综合提出一种有效的技术途径,这在各级地理信息空间数据采集和建库中具有重要意义。  相似文献   

Global Landscapes: Teaching Globalization through Responsive Mobile Map Design     

Robert Roth  Stephen Young  Chelsea Nestel  Carl Sack  Brian Davidson  Julia Janicki 《The Professional geographer》2018,70(3):395-411

This article reports on the design and evaluation of Global Madison, a mobile map designed to support teaching and learning about globalization using Madison, Wisconsin, as a situated classroom. Our experience of place increasingly is mediated by mobile devices, opening new opportunities and challenges for research, industry, and education. Despite this rising popularity, few guidelines exist for creating and using mobile maps. Following tenets of user-centered design studies, we conducted two mixed-method evaluations of Global Madison to improve the tool and generate design insights that are potentially transferable to similar mobile mapping contexts: 244 students participated in an online survey after completing the tour and eighteen students were observed in the field. The evaluations generated new design considerations for mobile maps supporting situated learning, include: focus on critical issues that might leave students stranded, append location-based services with traditional mapping, enforce cognitive association between map and landscape, supply a consistent feed of information for new learners, encourage collaborative learning in the landscape, and promote student safety above all else.  相似文献   

Big Data from the Ground Up: Mobile Maps and Geographic Knowledge     

Craig M. Dalton 《The Professional geographer》2018,70(1):157-164

Consumer users of maps on mobile devices are producing noteworthy geographic knowledges in the contexts of their own lives that are distinct from those of professional data scientists. By leveraging the streaming nature of big data in mobile maps and zooming multiscalar views, consumer users' mobile map practices produce a popular, multiscalar form of visual geographic knowledge that is both enabled and limited by its big data assemblage and associated technologies. The first half of this article outlines the role of consumer user practices amidst spatial big data assemblages, not for volunteered geographic information or aggregate analysis but for contextual, everyday use. Consumer users and their knowledges are coconstituted through mobile map viewing and as materially limited technological practices. This article focuses specifically on the consumer users' concept of scale in this context, for Web-based maps' multiscalar views differentiate them from older maps. The second half analyzes mobile map consumer users' concepts of scale in a series of focus groups that involved both questions and observing participants' actions with maps on their own phones. Instead of passively accepting maps at predetermined optimized scales from the map application, consumer users actively viewed the map across scales while searching but not while navigating.  相似文献   

DEM起伏纹理的视觉认知内涵与多变量消隐方法     

扈常钰  徐月雪  宋词  朱红春 《地球信息科学学报》2022,24(11):2115-2127

地形是在内外营力的共同作用之下综合形成的,不同类型的地形具有不同的起伏形态特征,从全局或宏观的观测视角,可以视觉感知到这种地形起伏及其特征规律。纹理是众多物体表面呈现的有规律的线条组合,DEM作为地形的数据表达,不同地形类型区域的起伏形态具有纹理的显著表征。目前,对于DEM纹理研究主要是从DEM影像认知的角度出发,利用图像纹理的计算方法进行地形纹理对象描述和指标的提取,并基于获取的纹理对象进行区域地形特征分析和地貌类型的分类,在视觉上的反映存在不足。DEM起伏纹理作为一种基于某种观测视角和尺度的地形要素组合对象,首先需要对其进行系统的视觉认知,明确基于视觉认知的DEM起伏纹理构成要素和不同视觉变量控制的纹理要素组合结构,通过实现DEM起伏纹理的多维可视化建模,达到DEM数字地形建模的抽象与简化。基于此,本文以DEM地形起伏纹理为研究对象,对DEM起伏纹理进行视觉认知,明确DEM起伏纹理的涵义并建立提取方法,使用建立的方法实现了DEM起伏纹理的提取,取得了较好的提取效果。从视觉感知的机制出发,确定了决定视觉感知结果的视觉变量组合。确定了包含景深、长度和邻域等用于视觉综合的参数,设计建立了多变量的DEM起伏纹理消隐方法。最后设置视觉变量并使用该方法实现了DEM起伏纹理的消隐,消隐后DEM起伏纹理的数量分别降低了45.2%和53.2%,视觉上也取得了较理想的结果,具有一定的应用价值。  相似文献   

等距离纬度等量纬度和等面积纬度展开式   总被引：1，自引：1，他引：0  

边少锋  纪兵 《测绘学报》2007,36(2):218-223

对数学制图学中经常遇到的等距离纬度、等量纬度和等面积纬度展开式进行新的研究。借助计算机代数系统强大的数学分析功能,给出这些纬度用偏心率幂级数形式表示的正解公式,并且以此为基础,给出纬度用偏心率幂级数形式表示的反解展开式,与以往数值形式表示的反解公式不同,这些反解展开式是以符号形式给出,研究表明计算机代数系统的应用不但极大地提高公式推演的效率和准确度,而且反解系数可以表示为更简单和更便于记忆的符号形式。  相似文献   

采用斜拉式弯曲划分的曲线化简方法   总被引：1，自引：1，他引：0  

钱海忠  武芳  陈波  张景辉  王家耀 《测绘学报》2007,36(4):443-449,456

线要素化简一直是自动制图综合中的重要研究内容。分析已有线化简算法在线弯曲形态保持和单调弧段划分时只考虑一侧等不足,提出线要素的斜拉式弯曲划分和化简新方法。该方法对线要素采用斜剖方式划分弧段,兼顾线要素两侧的弯曲形态;识别出每个划分的单调弧段是U型弧段还是V型弧段,是大弧段还是小弧段,从而分别对其进行不同的处理;在处理过程中,每化简完一个单调弧段,重新对线要素进行弧段划分,然后再次对每个单调弧段进行化简,以此类推,因此该算法是一种动态化简过程。实例显示,本算法在线要素特征点保持、u型弧段和V型弧段保持、大弯曲的保持、整体形态保持等方面非常有效,且化简率非常高,充分证明本算法的科学性和优越性。  相似文献   

中国现代地图学发展的成功经验     

廖克 《测绘科学》2007,32(5):5-8

系统分析和阐明了中国现代地图学发展的成功经验,主要包括:地图事业的发展必须适应国家经济建设和社会发展的需要;重视和积极培养各层次的地图学专业人才;重视地图学的理论研究,不断提高地图编制技术水平,实现由传统工艺向数字化与自动化的根本变革。  相似文献   

线状要素化简算法的分析与评估   总被引：1，自引：0，他引：1  

陈波  朱鲲鹏  薛本新 《测绘科学技术学报》2007,24(2):121-124

线状要素是地图中量最大、形式最多样的要素,它们的化简在自动制图综合中非常重要.目前对线状要素化简的算法研究较多,但其化简质量却少有研究.针对化简算法的基本要求,提出了易于操作的评估化简算法质量的6个方面:面积差、弯曲度、最大拐角比率、化简变化趋势、化简结果一致性和自相交性.通过大量实验,比较了Douglas-Peucker等算法的化简效果,最后对化简中的自相交问题提出了相应的改正措施.  相似文献   

Vario-scale data structures supporting smooth zoom and progressive transfer of 2D and 3D data     

Peter van Oosterom  Martijn Meijers 《International journal of geographical information science》2014,28(3):455-478

This paper introduces the concept of the smooth topological Generalized Area Partitioning (tGAP) structure represented by a space-scale partition, which we term the space-scale cube. We take the view of ‘map generalization as extrusion of data into an additional dimension’. For 2D objects the resulting vario-scale representation is a 3D structure, while for 3D objects the result is a 4D structure.

This paper provides insights in: (1) creating valid data for the cube and proof that this is always possible for the implemented 2D tGAP generalization operators (line simplification, merge and split/collapse), (2) obtaining a valid 2D polygonal map representation at arbitrary scale from the cube, (3) using the vario-scale structure to provide smooth zoom and progressive transfer between server and client, (4) exploring which other possibilities the cube brings for obtaining maps having non-homogenous scales over their domain (which we term mixed-scale maps), and (5) using the same principles also for higher dimensional data; illustrated with 3D input data represented in a 4D hypercube.

The proposed new structure has very significant advantages over existing multi-scale/multi-representation solutions (in addition to being truly vario-scale): (1) due to tight integration of space and scale, there is guaranteed consistency between scales, (2) it is relatively easy to implement smooth zoom, and (3) compact, object-oriented encoding is provided for a complete scale range.  相似文献   

The Bulger Case: A Spatial Story     

Les Roberts 《The Cartographic journal》2014,51(2):141-151

Abstract

This paper contributes to debates in the emerging field of cinematic cartography () by exploring the ways in which strategies of digital cinemapping can function as tools of critical spatial practice and urban wayfinding. More specifically, the paper considers the scope for digital video technologies to reshape, contest and ‘ground’ spaces of urban representation and the ‘spatial stories’ these bring into play. Basing my analysis on the mediation of the events surrounding the abduction and murder of the 2-year-old boy James Bulger in 1993, I examine the case as a constellation of spatial narratives within which I weave my own spatial story in the form of a video mapping of the abduction route (in Bootle near Liverpool) and the responses and issues this further mediation has provoked. Methodological reflections on the map-making process are discussed alongside narratives generated by the video on YouTube. The paper argues that, by adopting practices of wayfinding, and by being critically attentive to the ways in which film and video-making practices are also spatial practices, moving image cartographies can provide insights into lived and embedded spaces of memory, and the hidden or muted spatial stories to which they play host.  相似文献