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).     

Contextual neural gas for spatial clustering and analysis

This study aims to introduce contextual Neural Gas (CNG), a variant of the Neural Gas algorithm, which explicitly accounts for spatial dependencies within spatial data. The main idea of the CNG is to map spatially close observations to neurons, which are close with respect to their rank distance. Thus, spatial dependency is incorporated independently from the attribute values of the data. To discuss and compare the performance of the CNG and GeoSOM, this study draws from a series of experiments, which are based on two artificial and one real-world dataset. The experimental results of the artificial datasets show that the CNG produces more homogenous clusters, a better ratio of positional accuracy, and a lower quantization error than the GeoSOM. The results of the real-world dataset illustrate that the resulting patterns of the CNG are theoretically more sound and coherent than that of the GeoSOM, which emphasizes its applicability for geographic analysis tasks.     

量化地图图形符号透视化的展现研究

量化地图是传递数量信息的载体 ,是量化信息可视化的图形表达方式之一。量化符号透视化是按照透视原理来设计符号 ,在对透视符号分析的基础上 ,从数学基础的角度将透视符号分为比率符号透视化、透视坐标系量化图形与透视立体地图 3类。量化符号透视化有助于某些数量指标的表达 ,提高量化地图的展现力。     

在3D光栅地图中对高度的符号化表示

分析了三维图传输特点,以直观性、一览性、精确性为目标,尝试在用3D光栅图传输三维度地理空间数据的过程中,采用符号化方法,有效、准确地传输第三维度数据。     

大连金普新区建设变化监测项目的探讨

通过大连金普新区建设变化监测项目的工作实践,系统地阐述了该项目的内容、方法、生产工艺和质量控制,对保证项目的顺利进行、保障数据的真实可靠具有重要意义。     

地形图脚本文件自动生成的研究与应用

AutoCAD脚本文件编写简单,可将不同的命令组合起来并按照一定的顺序连续地执行,可用于对分幅地形图数据的批量处理。本文利用程序开发了脚本文件自动生成程序,较大地提高了图形编辑处理的效率。     

分省普通地理图数据建库与编研——以新世纪版《国家普通地图集》为例

新世纪版《中华人民共和国国家大地图集》编研项目的重要成果之一是《国家普通地图集》,而《国家普通地图集》的主要内容是分省地理图。新版分省地理图的编研,本着"先建库、后制图"的设计理念,充分利用国家1:1000 000基础地理信息数据库成果,并采用基于数据库的自动配图技术。本文主要介绍分省地理图的成果形态、编制技术路线、工艺流程和关键技术等。     

The Use of Maps in Turkish Newspapers

This study analyzes the use of maps in Turkish newspapers in order to evaluate their potential to contribute to the enhancement of geographic knowledge in society. This study reviewed the content of three Turkish newspapers published between January 2008 and August 2012. Only 835 maps were used in the newspapers during the study period, or an average of 278 maps per newspaper. During the study period, about 15,720 news articles were published per month in the three newspapers; however, only five of these were illustrated with a map. The study reveals the potential for Turkish newspapers to increase society's geographic awareness with additional published maps.     

A fitted B-spline method to derive a representative 3D axis from a set of multiple road traces

Collecting data to make an accurate representation for roads is an expensive process. Nevertheless, there is a collaborative alternative for this endeavour. Many drivers, bicyclists and even pedestrians have consumer-grade GPS (low precision) on their smartphones or electronic devices. Those users could transfer their road or track itineraries to a large database in order to compute the accurate geometry of any route. For each road or track, the large database would have many traces from which to infer an accurate representative 3D axis. Several inference methods have been proposed but most of them to fit the 2D trace data set. We propose to create a set of ordered points from the 3D trace data set and then using the least-squares method, to fit a B-spline curve to those points. The resulting parameterized curve will be a good representative 3D axis of the traces. Our method considers the nodes to be evenly separated and allows the system to recommend the number limit of nodes necessary to reach the convergence.     

美丽绘于笔下 幸福感在心中——浅析“美丽江城 幸福武汉”系列专题地图的设计及特点

地图是城市面貌最直观的反映,通过它不仅能够微观表示城市规划、建设、发展、变化,而且能够反映历史、人文、风土、人情。本文以"美丽江城幸福武汉"为主题,充分挖掘地理信息资源,按照系列化的设计思路,从不同的角度设计专题,将武汉全方位呈现在读者面前。