Minimum conformal mapping distortion according to Chebyshev’s principle: a case study over peninsular Spain     

M. Bermejo  J. Otero 《Journal of Geodesy》2005,79(1-3):124-134

Defining the distortion of a conformal map projection as the oscillation of the logarithm of its infinitesimal-scale σ, Chebyshev’s principle states that the best (minimum distortion) conformal map projection over a given region Ω of the ellipsoid is characterized by the property that σ is constant on the boundary of that region. Starting from a first map of Ω, we show how to compute the distortion δ₀(Ω) of this Chebyshev’s projection. We prove that this minimum possible conformal mapping distortion associated with Ω coincides with the absolute value of the minimum of the solution of a Dirichlet boundary-value problem for an elliptic partial differential equation in divergence form and with homogeneous boundary condition. If the first map is conformal, the partial differential equation becomes a Poisson equation for the Laplace operator. As an example, we compute the minimum conformal distortion associated with peninsular Spain. Using longitude and isometric latitude as coordinates, we solve the corresponding boundary-value problem with the finite element method, obtaining δ₀(Ω)=0.74869×10⁻³. We also quantify the distortions δ_l and δ_utm of the best conformal conic and UTM (zone 30) projections over peninsular Spain respectively. We get δ_l=2.30202×10⁻³ and δ_utm=3.33784×10⁻³.  相似文献   

地图出版系统中公路类符号绘制的解决方法     

邓术军陈四清  刘宏林 《测绘学院学报》2005,22(2):134-135,138

在地图符号中公路类符号的绘制具有其特殊性，必须进行特殊处理才能正确显示。文中首先介绍了常见的两种处理方法，并分析了其存在的问题；然后针对地图出皈的要求，在全数字地图出版系统中，利用STL标准模板库技术，对公路要素进行批处理绘制，很好地解决了公路类符号的绘制问题。  相似文献   

网络地图人性化界面设计   总被引：10，自引：0，他引：10  

郑束蕾  陈毓芬 《测绘学院学报》2005,22(4):300-303,306

目前网络地图发展迅猛,但界面设计缺少理论指导,仍存在着许多问题.文中首先研究了网络地图的特点和界面内容,对目前网络地图界面设计中存在的突出问题进行归纳.接着提出了基于认知心理学理论的一般性网络地图界面设计原则.最后,对网络地图的用户层次进行分类,举例说明上述设计原则在人性化网络地图界面设计中的应用.  相似文献   

Subsidence hazard avoidance based on geomorphological mapping in the Ebro River valley mantled evaporite karst terrain (NE Spain)   总被引：1，自引：6，他引：1  

F. Gutiérrez-Santolalla  M. Gutiérrez-Elorza  C. Marín  C. Maldonado  P. L. Younger 《Environmental Geology》2005,48(3):370-383

In the valley of the Ebro River to the southeast of the city of Zaragoza (NE Spain), the dissolution of evaporite sediments (gypsum, halite and Na-sulphates) which underlie alluvial deposits gives rise to numerous sinkholes. These sinkholes are a potential hazard to human safety, particularly where they develop in a catastrophic way. Even slow-developing sinkholes are problematic, as they damage urban and agricultural infrastructure, necessitating costly repairs and vigilant maintenance. To assist in developing avoidance strategies for these hazards, the factors controlling sinkhole occurrence have been assessed using geomorphological maps produced from aerial photographs for 1956 and 1981. Important controls on sinkhole development are found to include underlying geological structure (manifest in preferred orientations of sinkholes on the azimuths N130-150E and N30-40E), and the presence of glauberite in the groundwater flow path, which apparently promotes accelerated gypsum dissolution. Perhaps surprisingly, alluvium thickness does not appear to significantly correlate with the density of sinkholes on the floodplain in this area. The maps for 1956 and 1981 reveal that both human activity and natural processes can serve to obscure the true density of sinkhole development. For instance, a large number of sinkholes which were conspicuous in 1956 have since been back-filled by farmers. In the most fluvially active zone of the Ebro valley (the meander belt), the relatively low density of sinkholes compared with adjoining zones suggests that subsidence is being masked by morpho-sedimentary dynamic processes (aggradation and erosion). Careful geomorphological mapping for different time periods yields a much more accurate impression of the frequency of sinkhole development than would be gained from surveying currently visible sinkholes in the area of interest.  相似文献   

Rhumb Lines and Map Wars: A Social History of the Mercator Projection by Mark Monmonier     

Dennis Fitzsimons 《The Professional geographer》2006,58(4):497-499

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城市多媒体电子地图系统探讨   总被引：2，自引：0，他引：2  

武钦琳 《现代测绘》2006,29(3):45-46

为及时反映城市信息的多媒体电子地图融合了数字制图技术、GIS技术、多媒体技术等多种高科技手段,为政府部门、公司企业、社会公众构建了一套便捷的、可视化的空间信息服务平台。介绍了多媒体电子地图的一些特点和重要性,并对多媒体电子地图的制作方法和设计理念等方面进行了探讨。  相似文献   

Excel、Word与CASS(AutoCAD)在测量绘图中的应用     

张广伟 《北京测绘》2006,(2):8-12

将常用的办公软件:Excel、Word等与CASS绘图软件相结合,提供了解决绘图中常见的批量标注、插值和参数计算等问题的方法,改变了传统的纯手式输入的方式,较好的提高了数据处理的效率和准确性。  相似文献   

网络上分级统计地图制图软件的设计与开发   总被引：1，自引：0，他引：1  

章莉萍  郭庆胜 《测绘信息与工程》2006,31(3):47-49

分析了网络环境中分级统计图表达信息的特点,阐述了交互式分级统计图的设计方法和思路,运用JavaApplet设计并实现了网络上分级统计地图制图子系统。  相似文献   

基于ArcGIS Engine的地图符号制作工具的设计实现   总被引：3，自引：1，他引：3  

张俊岭  熊卫东  夏斌 《测绘信息与工程》2006,31(5):43-44

分析了ArcGIS Engine符号体系特点,设计了一套基于ArcGIS Engine的符号制作工具,采用C#语言开发实现。  相似文献   

网络环境下分区统计地图制图子系统的设计与实现   总被引：1，自引：0，他引：1  

姬星怡  郭庆胜 《测绘信息与工程》2006,31(5):47-49

分析了网络环境下分区统计地图表达信息的特点,根据其可视化地理统计信息的需要,运用Java Ap-plet技术,设计和开发了网络环境下交互式分区统计地图制图子系统。  相似文献