用流形坐标差异图提取高光谱影像潜在特征

等距映射和局部切空间排列降维后,低维流形坐标能够保留原始高光谱影像中地物光谱信息,用于提取原始影像的潜在特征。然而这两种流形方法的理论差异导致其低维坐标继承光谱信息的能力不同,对比这两种流形坐标可凸显出原始影像内部的潜在特征。因此,本文基于等距映射和局部切空间排列非线性降维,提出两种流形坐标的差异图法来提取高光谱影像内部的潜在特征。首先,根据流形坐标的光谱解释确定两种坐标的每一维代表相同的光谱信息。其次,根据相同的光谱特征,归一化两种流形坐标并调整坐标轴方向,统一两种坐标到相同的坐标框架。最后,通过加权流形图相减得到坐标差异图,采用经典的图像处理方法提取潜在特征。采用两个实验并对比等距映射和局部切空间排列方法的降维结果来验证本文方法。结果表明,流形坐标差异图能够成功提取单一流形结果无法得到的潜在特征,如靠河岸的浅水区域和大场景沼泽地中的低分辨率道路。这为高光谱影像的潜在特征提取研究提供了一种新方法。     

Continuity markers as an aid for children in finding the peripheral continuity of world maps

ABSTRACT

Many map readers, including both children and adults, find it difficult to determine where they would be located along the edge of a world map after crossing that edge. Different types of markers have long been drawn close to the map’s edge – for example, in an atlas – to help map readers identify the map upon which they will find themselves if that edge is passed. In this study, a method similar to that used to show the continuity between maps in an atlas has been tested to determine whether continuity markers can also be used to help map readers find a world map’s actual peripheral continuity. The study involved children between the ages of 10 and 13 years and showed that continuity markers do help children determine the map’s actual peripheral continuity, in combination with a lesson that describes how to find the actual peripheral continuity of a world map. This article, therefore, concludes that continuity markers for world maps can be a useful part of map design that clarifies how the edges of a world map fit together for children who have learned to use this tool.     

Jacques Bertin,from classical training to systematic thinking of graphic signs

ABSTRACT

Nearly 50 years after the publication of the first French edition of Sémiologie Graphique, Jacques Bertin’s thought is more than ever alive, in cartography as well as in various other disciplines, such as graphic design or visual data analysis. This article recalls the main elements of Bertin’s career and puts forward the salient points of his reflection on graphics. Beyond many conceptual or technical innovations, Bertin’s essential originality appears to be his attempt to propose a general framework for graphical representations.     

基于Android的大学生兼职系统设计与实现

基于Android的面向大学生兼职系统具有分类检索、收藏订阅、GPS定位、空间查询、分享到新浪微博、信息对比等功能,方便用户随时查询适合自己的兼职信息;利用ArcGIS的空间查询功能,实现了在用户感兴趣区域内查询兼职信息的功能,并且与现在热门的微博联系起来,可分享给好友。     

Deconstructing Galbraith: A Geostatistical Analysis of Cartographic Intent

Abstract

This study uses cartometric techniques to reveal cartographic design considerations operative in Frank H. Galbraith’s 1897 railway mail service training maps. Galbraith’s maps make extensive use of humorous cartouches intended to serve as mnemonic devices for learning railway mail service routes. Poisson and quadrat point pattern analyses are performed on all eight maps in the series to determine whether the mimetic symbols are clustered along the railway mail routes or dispersed throughout the mapped spaces to achieve better graphic balance. Evidence overwhelmingly indicates that the placement of the mnemonic symbols was primarily driven by design considerations. The study therefore proves that it is possible to use cartometric techniques to deconstruct the map document to determine the cartographic design principles operative during the map's construction.     

基于Panorama Studio的街景网络快速发布关键技术研究

街景影像与电子地图、遥感影像结合提供给人们一种多尺度、多视角认识地球的新途径。本文探讨了移动测量车、手持相机全景影像的获取方法、基于Panorama Studio的全景影像拼接方法,以及网络环境下全景影像的发布,结合ArcGIS Server发布的地图,探讨了基于JavaScript的街景与地图交互等关键技术,形成一整套全景影像获取、拼接、发布技术流程。在此基础上实现了高速公路带状地形图街景网站的原型设计。     

Challenges related to interdisciplinary use of digital mapping technology in primary and lower secondary schools

The article reviews some learning objectives in the Norwegian core curriculum for four subjects in compulsory school education, namely science, social science, mathematics, and physical education. The subjects are examined with respect to maps, including map use, digital mapping tools, coordinate systems, and scales. Primary and lower secondary school pupils’ knowledge of maps was investigated before and after a group mapping project. Among three indicators, two showed statistically significant improvements in the pupils’ level of confidence when studying data with the aid of maps. The learning outcome is discussed in an inquiry-based and interdisciplinary pedagogical frame. In addition, the findings reveal that the four subjects have significantly different objectives and rates of progression regarding maps and map use. Based on the results of the group project, the author argues in favour of bringing the four curricula into more parallel learning curves. In order to facilitate interdisciplinary projects, he considers it would be interesting to coordinate the different subject curricula in the future, and recommends that attempts should be made to harmonise competence objectives that are part of several subjects in order to facilitate interdisciplinary projects in the next revision of the core curriculum in Norway.     

The Spatial Knowledge of Indigenous People in Mountainous Environments: A Case Study of Three Taiwanese Indigenous Tribes

This article recounts information gleaned from a case study of three indigenous tribes in Taiwan regarding the origin and nature of their spatial knowledge. Sketched mental maps and GIS 3D virtual environment (VE) are used by indigenous elders and hunters to delineate their traditional territories. Spatial components representing the predominant spatial elements are identified. Spatial structures used for locational positioning are analyzed, as are spatial reference systems for orientation and movement. The results show that spatial components are used for daily activities, as well as having historical and cultural meaning; a quadrant structure is used for spatial positioning; and instead of using the directional reference system of east, south, west, and north, these indigenous people rely on the orientation analogies of uphill, downhill, upstream, and downstream for direction.     

LETTERS TO THE PRESIDENT OF THE ASSOCIATION

Topographic shading curtails the period and complicates the geographic patterns of insolation in mountainous areas. Maps derived from oblique aerial photographs of shadow lines cast by the irregular, mountainous east horizon in Provo, Utah are used as a case study to illustrate an alternative to existing techniques of solar radiation data collection. For study areas of several hundred square kilometers, this method may be superior in resolution and at the same time more error free and economically feasible than other methods. Measurement of solar inputs received at sample stations scattered through the mapped area show that the phenomenon of topographically delayed sunrise has a distinct effect on daily totals of radiation in the manner suggested by the maps.     

Disaggregating population density of the European Union with CORINE land cover

This article describes and compares six disaggregation methods used to produce a dasymetric population density grid of the European Union at a 100 m resolution. Population data were initially available at commune level. The main ancillary information source was CORINE land cover, a land cover map distributed by the European Environment Agency. Information from the Eurostat point survey, land use/cover area frame survey, was also integrated in the parameter estimation of some of the approaches tested. Accurate population data for 1 km cell grids were provided by the Statistical Offices of Austria, Denmark, Finland, the Netherlands, Northern Ireland, Estonia and Sweden. These data provided the basic reference to quantify the accuracy of each method. The best results were obtained with a modified version of the limiting variable method (Eicher, C. and Brewer, C., 2001. Dasymetric mapping and areal interpolation: implementation and evaluation. Cartography and Geographic Information Science, 28, 125–138) that could be implemented, thanks to the national reference grids. For other methods the parameters could be estimated without using the reference grids; among them a method based on logit regression gave the best results. Compared with the traditional choropleth maps that represent a homogeneous density in each commune, the accuracy improvement of the disaggregated maps ranged between 20% and 67% (between 46% and 67% for the best method).