Contrasting static versus dynamic-based typologies of land cover patterns in the Lisbon metropolitan area: Towards a better understanding of peri-urban areas

Peri-urban areas are usually a heterogeneous mosaic of rural, urban and natural systems which are quite dynamic across time. In this paper we contrast a static and a dynamic-based classification of local administrative units (LAU) in the Lisbon Metropolitan Area (LMA) to gain further insights onto the current land cover patterns and recent land cover changes in urban and peri-urban areas of the LMA. Using 16 landscape pattern indicators, we characterized the 211 LAU in the region contrasting a static (2006 data) and a dynamic-based (changes during the period 1990–2006) approach, and used cluster analyses to identify LAU typologies. Using the static approach we identified seven types of LAU, of which two were clearly urban, two could be considered rural, and three could be considered peri-urban. These latter could be distinguished among themselves by the landscape matrix type where urban areas were inserted. The dynamic-based approach yielded five types of LAU with specific trajectories in time, ranging from stable to highly dynamic. The frequency of the different dynamic typologies was not independent from the static ones, with typically urban areas being predominantly stable and rural areas having characteristic and exclusive trajectories of change. Peri-urban LAU were mostly moderately dynamic but shared a typology profile mixing highly dynamic LAU with moderately dynamic and stable ones. The combination of a static and dynamic view provides added value for the formulation of spatial planning policies in peri-urban areas.     

The residential segregation of San Antonio,Texas in 1910: an analysis of ethno-racial and occupational spatial patterns with the colocation quotient

The segregation of cities can be traced to a time when the compartmentalization of space and people was based on factors other than race. In segregation research, one of the limiting factors has always been the geographic scale of the data, and the limited knowledge that exists of segregation patterns when the household is the unit of analysis. Historical census data provides the opportunity to analyze the disaggregated information, and this paper does so with San Antonio during 1910. A spatial analysis of residential segregation based on race, ethnicity, and occupations is carried out with the colocation quotient to map and measure the attraction of residents. Results reveal the presence of residential segregation patterns on different sectors of the city based on households’ ethno-racial and occupational attributes; therefore, providing evidence of the existence of residential segregation prior to the commonly cited determinants of segregation of the 20th century.     

Zero graffiti for a beautiful city: the cultural politics of urban space in San Francisco

San Francisco, like many cities in the United States and across the world, has an official zero-tolerance policy on graffiti. In this article, we examine the academic literature concerned with graffiti and then present a case study of zero-tolerance abatement policies in San Francisco. Our analysis yields three main findings. First, zero-tolerance policy stimulates an anti-graffiti industry with vested interest in perpetuating an endless war for control of public space. Second, zero tolerance may generate an unintended result—the proliferation of tags and other forms of graffiti that people tend to dislike the most. Third, we find little evidence that the general public shares the same desire for zero tolerance as the San Francisco Government. Ultimately, we believe that more nuanced readings of graffiti allow greater numbers of people to make sensible, local, place-specific policies regarding graffiti.     

Volunteered geographic information research in the first decade: a narrative review of selected journal articles in GIScience

ABSTRACT

More than 10 years have passed since the coining of the term volunteered geographic information (VGI) in 2007. This article presents the results of a review of the literature concerning VGI. A total of 346 articles published in 24 international refereed journals in GIScience between 2007 and 2017 have been reviewed. The review has uncovered varying levels of popularity of VGI research over space and time, and varying interests in various sources of VGI (e.g. OpenStreetMap) and VGI-related terms (e.g. user-generated content) that point to the multi-perspective nature of VGI. Content-wise, using latent Dirichlet allocation (LDA), this study has extracted 50 specific research topics pertinent to VGI. The 50 topics have been subsequently clustered into 13 intermediate topics and three overarching themes to allow a hierarchical topic review. The overarching VGI research themes include (1) VGI contributions and contributors, (2) main fields applying VGI, and (3) conceptions and envisions. The review of the articles under the three themes has revealed the progress and the points that demand attention regarding the individual topics. This article also discusses the areas that the existing research has not yet adequately explored and proposes an agenda for potential future research endeavors.     

After the 1997 financial crisis in Bangkok: The behaviour and implications of a new cohort of street vendors

After the 1997 financial crisis, many retrenched workers preferred not to return to provincial homes but remained in Bangkok to establish informal retail businesses in branded and other consumer products. In contrast to traditional street vendors, who specialized in food items primarily catering for low‐income customers, and focused on high volume, these ‘new generation’ street vendors also adopted more formal business practices. Given their greater sophistication and better education, we hypothesized that they would be more organized advocates of vendors' rights and thus more prone to conflicts with municipal authorities. Based on interviews, however, we found that new generation vendors are adaptive to location and business strategy, and prefer a low profile in dealing with officialdom. By contrast, traditional vendors remained more tied to particular spaces, are more likely to stand up for their rights to use public space and, because they expect more from government, are more prone to conflicts with municipal authorities. Our findings relate to ongoing discussion on the rights and needs of street vendors to access urban public space and the responsibilities of authorities to meet and provide for these informal sector livelihoods that make up a significant share of the national economy in Thailand, as elsewhere in the global South.     

道路建设对秦岭山区社会—生态系统的影响——一个社区恢复力的视角

社会—生态系统具有不可预期、自组织和多稳态体制等特征。道路建设是区域发展重要的干扰驱动因素,对局域社会—生态系统产生多要素和跨尺度的影响。基于社会—生态系统恢复力的相关概念和分析框架,以道路建设为切入点,借鉴社会经济连通度概念,以商洛市为例,从区域（local）和社区（community）两个尺度,分析道路建设对欠发达山区社会—生态系统的综合影响。将社会—生态系统分解为经济增长、生态景观格局和乡村发展3个维度,选取商洛市统计年鉴、商州区遥感影像和典型农户调查3类数据,结合数理模型、遥感与GIS技术和问卷统计分析,对道路建设与经济发展,道路网络与景观破碎度变化以及高速公路（国道）建设对乡村社区恢复力的影响进行了研究。主要结论包括：① 道路扩张成为减贫的原因,却并非经济增长的动因,而经济增长却是道路网络扩展的原因;② 道路建设增加了当地生态景观的破碎度,却提高了社会连通度,并且景观破碎度与社会连通度之间呈正相关;③ 在乡村社区尺度上,道路建设与社区恢复力之间呈现复杂关系,乡村社区恢复力可以从集体记忆、生计多样性和适应能力3个准则层选取相应的替代指标,通过对农户调查来分析和解释,运用逐步回归分析,识别了乡村社区恢复力的影响因素。最后,对基础设施建设影响下的欠发达山区乡村恢复力的研究方向进行了探讨。     

黄土丘陵沟壑区乔灌草植物空间优化配置——以甘肃省定西地区为例

黄土丘陵沟壑区水土流失的影响因素有气候、植被、土壤、地形等,而乔灌草植物在空间上的不合理配置是造成该区水土流失严重的主要原因之一。本文选择研究区内限制植物生长与分布的4个关键环境因子 (高程、坡度、坡向和降雨量),利用多属性决策分析(MCDA)的方法,探讨乔灌草植物在空间上的优化配置,将整个研究区划分为5类乔灌草植物空间优化配置主模式和18类乔灌草植物空间优化配置子模式;同时,应用GIS聚类分析与统计分析方法,对所划分的乔灌草植物空间优化配置模式进行空间布局分析。结果显示:农民赖以生存的经济林/农林复合配置模式和农田/庭院经济配置模式是研究区的主要配置模式,占配置模式总面积的76.02％。