'To define the indefinable': population classification and the census in South Africa

The population of many countries, including South Africa, has been classified into discrete groups from colonial times until the present day, for purposes of census enumeration. A reading of the census results requires an understanding of the subtleties and shifts of the classification system, which were frequently related to a definition of legal and political rights, including place of residence. The national census has tended to reinforce the groups it was initially meant only to observe.     

The viability of the genetic algorithm geodemographic modelling in the case of Korean DIF zoning

Development impact fees (DIF) are used for the provision of public infrastructure services to adequately serve new developments. Korean Ministry of Land, Transport, and Maritime Affairs introduced the DIF zoning in 2008 and, like its US counterpart, it requires Korean localities to designate specific districts called ‘DIF zones’ based on the local population growth rate. This study examines the genetic algorithms as a method for DIF zoning-related geodemographic modelling using the Korean National Geographic Information Systems as property-level ancillary data. A borough of Hwasung City is taken as the case area since the city internally collected population data by ward-level enumeration areas for DIF zoning in 2008. The gridded population map is built from this source enumeration area population data to select the training dataset. The functional form of the genetic algorithm model has been formulated to have a hierarchical weighting system in which categorical weights of variable groups and individual weights of subordinate variables are sought bilaterally. The model is run by a carefully pretested set of reproductive plan parameters and the consequences are compared with the conventional regression models. It is found that the genetic algorithm solutions are quite comparable to the ones obtained by the regression methods, and it seemed, in this regard, worth adopting the two approaches simultaneously in a complementary manner to take unique advantages of each other either in facilitating the analysis processes or in obtaining more promising outputs for the DIF zoning as well as other geodemographic applications.     

Cities On the Plains: The Evolution of Urban Kansas

The process of congressional redistricting, delineating boundaries for districts in which voters elect members to the U.S. House of Representatives, has always been an expensive and controversial process. Congressional districts (CDs) are redrawn due to changes in population reflected by the decennial census to ensure equal representation. Laws and regulations literature identifies eight criteria that may be considered when determining the boundaries of CDs and this article focuses on one of those criteria, maintaining communities of interest (COIs). This criterion requires states to preserve these boundaries when delineating CDs but fails to define a COI. This research proposes and evaluates two approaches to define a COI and examines the extent to which this criterion has been adhered to. One definition uses Thiessen polygons and census designated places to delineate COIs based on known cultural places, whereas the other definition uses cluster analysis to group together people with similar sociodemographic characteristics. The results show that the two definitions are feasible for defining a COI. Furthermore, the states largely maintain the COI boundaries within their CDs by only splitting, at most, 17.1 percent of the COIs defined. Existing literature shows that maintaining COIs within CDs leads to higher voter participation and engagement, as well as better representation. The results show that if either definition was adopted, states could comply with this criterion with relative ease. Furthermore, a standard definition could help reduce the cost and controversy surrounding the redistricting process.     

The quality and qualities of population statistics, and the place of the census

Population counts are a key anchor for much of the official statistical system and the benchmark for many commercial and research surveys and analysis. Statistical offices around the world face a wide range of challenges in counting their population, most particularly in the years between censuses, as population flows become much freer and family structures continue to evolve. This paper considers these issues, reviewing how population counts have evolved over time in the UK and other countries. The paper also looks to the future, considering ways in which population count methodology might develop.     

The turnaround in Australia: some first observations from the 1991 census

"The aim of this paper is to utilise recently released census results to examine patterns of population change in non-metropolitan Australia during the 1986-91 period, focusing particularly upon the net migration component of that change. The paper presents an overview of recent trends in population change in non-metropolitan areas and then moves to an analysis of net migration patterns in non-metropolitan local government areas during the late 1980s using a Life Table Survival Ratio technique to estimate net migration. It appears that the trends observed in the early 1980s have continued into the late 1980s and early 1990s, and that overall the 'turnaround' is slowing down and becoming more diversified, more complex, and much less predictable in the 1990s."     

Housing submarket classification: The role of spatial contiguity

Understanding housing submarket structure is of crucial importance to both public and private agencies. It can also help current and future homeowners make informed decisions on their residential choices. Current research on submarket focuses on comparative analyses of different classification techniques. Few studies, however, have examined the function of spatial contiguity on housing submarket classification. To address this issue, this paper developed a spatially constrained data-driven submarket classification methodology to obtain spatially integrated housing market segments. Specifically, a data-driven model based on principal component analysis and cluster analysis was developed for delineating housing submarkets. Within the model, a number of location attributes were used for principal component analysis, and the geographic locations of houses were also incorporated in the cluster analysis. The performance of this method was compared with other unconstrained data-driven techniques and a priori classifications using three measurements: substitutability, spatial integrity, and similarity. Results indicate that spatially contiguous submarkets can be obtained without compromising housing hedonic model accuracy and attribute homogeneity.     

Simulating trends in poverty and income inequality on the basis of 1991 and 2001 census data: a tale of two cities

How much does the 2001 census tell us about the changes in people's life in British cities and regions since 1991? This paper attempts to answer this question by telling the stories of two British northern cities: Leeds and Sheffield. In particular, the paper investigates and compares socio-economic change in these cities on the basis of actual 1991 and 2001 census data as well as estimated non-census data. A static spatial microsimulation model is used to combine the outputs of the 1991 and 2001 censuses of UK population with data from the British Household Panel Survey (BHPS) data. In particular, selected Small Area Statistics (SAS) tables from the 1991 and 2001 censuses are used as constraints in the spatial microsimulation modelling exercise, which aims to reweight BHPS household records so that they satisfy these constraints. The paper briefly discusses the change in these census variables across different localities of the two cities. It is then shown how the changes in these variables affect the simulation of non-census variables. Further, the microsimulation model is used to estimate the trends in income inequalities and child poverty between and within the two cities. Finally, the paper discusses the implication of the research findings for policy formulation.     

MARC: a robust method for multiple-aspect trajectory classification via space,time, and semantic embeddings

ABSTRACT

The increasing popularity of Location-Based Social Networks (LBSNs) and the semantic enrichment of mobility data in several contexts in the last years has led to the generation of large volumes of trajectory data. In contrast to GPS-based trajectories, LBSN and context-aware trajectories are more complex data, having several semantic textual dimensions besides space and time, which may reveal interesting mobility patterns. For instance, people may visit different places or perform different activities depending on the weather conditions. These new semantically rich data, known as multiple-aspect trajectories, pose new challenges in trajectory classification, which is the problem that we address in this paper. Existing methods for trajectory classification cannot deal with the complexity of heterogeneous data dimensions or the sequential aspect that characterizes movement. In this paper we propose MARC, an approach based on attribute embedding and Recurrent Neural Networks (RNNs) for classifying multiple-aspect trajectories, that tackles all trajectory properties: space, time, semantics, and sequence. We highlight that MARC exhibits good performance especially when trajectories are described by several textual/categorical attributes. Experiments performed over four publicly available datasets considering the Trajectory-User Linking (TUL) problem show that MARC outperformed all competitors, with respect to accuracy, precision, recall, and F1-score.     

西藏冻融侵蚀的分级和评价

Freeze-thaw erosion is the third largest soil erosion type after water erosion and wind erosion. Restricted by many factors, few researches on freeze-thaw erosion have so far been done at home and abroad, especially those on the assessment method of freeze-thaw erosion. Based on the comprehensive analysis of impact factors of free-thaw erosion, this paper chooses six indexes, including the annual temperature range, annual precipitation, slope, aspect, vegetation and soil, to build the model for relative classification of freeze-thaw erosion using weighted and additive methods, and realizes the relative classification of the freeze-thaw erosion in Tibet with the support of GIS software. Then a synthetic assessment of freeze-thaw erosion in Tibet has been carried out according to the relative classification result. The result shows that the distribution of freeze-thaw eroded area is very extensive in Tibet, accounting for 55.3% of the total local land area; the spatial differentiation of freeze-thaw erosion with different intensities is obvious; and the difference in distribution among different regions is also obvious.     

The classification and assessment of freeze-thaw erosion in Tibet

Freeze-thaw erosion is the third largest soil erosion type after water erosion and wind erosion. Restricted by many factors, few researches on freeze-thaw erosion have so far been done at home and abroad, especially those on the assessment method of freeze-thaw erosion. Based on the comprehensive analysis of impact factors of free-thaw erosion, this paper chooses six indexes, including the annual temperature range, annual precipitation, slope, aspect, vegetation and soil, to build the model for relative classification of freeze-thaw erosion using weighted and additive methods, and realizes the relative classification of the freeze-thaw erosion in Tibet with the support of GIS software. Then a synthetic assessment of freeze-thaw erosion in Tibet has been carried out according to the relative classification result. The result shows that the distribution of freeze-thaw eroded area is very extensive in Tibet, accounting for 55.3% of the total local land area; the spatial differentiation of freeze-thaw erosion with different intensities is obvious; and the difference in distribution among different regions is also obvious.     

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).     

生态旅游资源分类与评价体系构建

生态旅游是不同于大众化旅游的一种保护环境的持续发展模式。生态旅游资源是以生态旅游的新视角去认识旅游资源而形成的一种新类型。在生态旅游资源构成中,生态环境不再只作为旅游资源的背景,甚至成为生态旅游的主要吸引因素。本文通过对构成生态旅游资源的生态旅游景观资源、生态旅游环境资源进行分析界定,尝试性地提出了景观和环境并重的旅游资源分类评价思想,初步创立了生态旅游资源的景观—环境分类方案;探索性地采用AHP方法构建了生态旅游景观资源与生态旅游环境资源相结合的定性与定量综合评价基本框架。     

The role of population change in widening the mortality gap in Scotland

The social gradient in health and mortality has been acknowledged for some time and, more recently, there is some evidence that the gap between the richer and poorer is widening in Britain. Other studies have also shown that health and mortality outcomes are worse in places that are experiencing population decline and better in places that are growing. This analysis examines, first, whether there is a mortality gap between the least and most deprived people in Scotland, second, whether this gap has widened since the 1980s and, third, whether the gap can be explained by patterns of population change. Our results demonstrate that the widening mortality gap in Scotland cannot be explained simply as an artefact of population change, even though it is widening most in those places that are experiencing population decline. This type of research is made possible by the reliable denominator population information provided in the 1981 and 2001 censuses.     

基于生态功能的河流等级划分及应用——以浙江省河流为例

河流等级划分是认识河流规律的一项基础性工作,对河流的治理和保护管理具有现实意义。现有的河流等级划分难以反映河流的时空特性,有的人为影响较大,有的不具备河流地貌特征,有的仅具备物理特征,有的仅方便行政管理。本研究基于河流连续体概念,综合了河流的物理、生物特征,引用北美新近提出的"基于生态功能的河流等级划分",阐明了对浙江省河流进行基于生态功能的等级划分意义。从流域尺度上构建了浙江省河流的等级层次结构,分析了浙江省河流各等级层次的物理特征和生态特征的共性和差异,明确了河流各等级层次的生态保护目标和相关对策。以钱塘江流域为例,对其进行了详细的等级划分,探讨了基于生态功能的河流等级划分在确定浙江省河流生态需水的作用及应用前景,并明确了在人类活动影响下,浙江省水行政管理机构在河流等级层次的相关管理范围和内容。     

基于六普数据的中国流动人口住房状况的空间格局

住房是流动人口融入城市、实现市民化过程中必须解决的关键问题。基于2010 年第六次人口普查数据,采用住房拥有率、租住房率、住房面积指数、住房不受干扰指数、住房质量指数和住房费用指数6 个指标考察流动人口的住房状况,并综合运用数理统计、空间自相关和系统聚类法揭示流动人口住房状况的属性特征、空间分布与集聚类型。研究发现,与城镇常住人口相比,流动人口的住房状况较差。从空间分布看,流动人口住房状况的各项指标具有显著的空间正相关,在空间分布上不仅存在集聚现象,而且有明显的集聚中心。研究结果还表明,流动人口住房条件综合状况可划分为较好、中等、中等偏下、较差4 级类型区,在全国尺度上的空间分布除个别类型外具有团块聚合的结构特征。在考虑社会公平的前提下,应分类解决不同类型区域流动人口的住房问题。     

基于“七普”的“胡焕庸线”两侧人口集疏新态势及影响因素

随着新型城镇化建设的推进,“胡焕庸线”两侧人口发展出现了新态势。本文基于第七次人口普查数据,依据地级尺度划定的“准胡焕庸线”,分析2010—2020年“胡焕庸线”两侧人口集疏模式的新特征,并探讨影响因素。研究表明：① “胡焕庸线”依然稳定,2020年东南半壁与西北半壁的人口比为93.5∶6.5;② 西北半壁人口份额仍然微增,但是增幅较之前明显下降; ③ 2010—2020年西北半壁人口集中化指数由降转增,西北半壁和东南半壁的人口分布集中化程度均有所提升;④ 东南半壁人口集疏分化不断强化,2010—2020年人口负增长区的面积占比已达54.22%,超过人口正增长区;西北半壁人口集疏的马太效应特征愈发明显,人口负增长区占比也已升至26.15%;⑤ 省会首府人口增长优势愈发突出,且西北半壁比东南半壁更为明显;⑥ 经济发展水平、城区人口规模等级、行政区划等级等因素与区域人口变动显著相关;西北半壁行政区划等级对人口增长的影响效应尤为突出。综合来看,西北半壁已经出现与东南半壁相似的人口集疏过程,人口集疏模式已突破了“胡焕庸线”。中国即将迎来人口总量拐点,人口城镇化进程逐步减速,密切关注“胡焕庸线”两侧人口发展的新特征,对推动全国各区域协调发展具有重要的战略意义。     

基于城乡人口变动视角的中国城镇化地域类型时空演变

城镇化是城镇和乡村人口变动共同作用的结果。本文从城乡人口变动的视角提出了城镇化地域类型的划分方法,基于历次全国人口普查数据,考察了中国城镇化地域类型的时空演变及其影响因素。研究发现中国的城镇化于1990年后进入快速阶段且当前仍在加速,但城镇化的实现路径存在较强的时空动态性：① 随着人口自然增长减缓和乡城迁移扩张,全国城镇化地域类型由城乡扩张型转变为城镇吸引型,乡村人口减少对城镇化的贡献持续增强;② 城镇吸引型是各地最主要的城镇化地域类型,但2010年以来大量地区因乡村人口加速外流而转变为乡村流失型,城乡扩张型地域的空间范围大幅收缩至西藏、上海等地,而城乡收缩型地域在东北地区的非省会城市大范围扩张;③ 经济性因素仍是当前中国城镇化的核心驱动因素,经济增长带动乡村人口外迁,工业化长期有利于城乡协调共进,而公共服务等社会性因素的作用仍然有限;④ 新型城镇化和乡村振兴的政策效应还有待发掘,西部城市群、中小城市的吸引力以及乡村地区的人口发展等问题仍需更多的研究关注。本文最后对中国城镇化的趋势性、动力机制和未来研究重点展开了讨论。     

The allocation of rights to public forests in Tasmania: a geographical critique

Change in spatial economies, industrial technologies and societal attitudes can make long-established systems of resource allocation inefficient. Through a detailed examination of the procedures by which publicly owned forest has been allocated in Tasmania, this paper illustrates spatial, economic and other inefficiencies that have become embedded in the concession system. Analysis shows that the long-term costs of transporting timber to processing sites could be significantly reduced by rationalization of concession boundaries. Recommendations are also made that would produce more efficient use of forest resources. Inter alia, the paper illustrates the vulnerability of peripheral economies to big business enterprises.