Population density and the accuracy of the land valuations in the 1798 federal direct tax

Abstract

The peculiar operation of the 1798 federal direct tax has led scholars to question whether tax officials reported the land valuations from their districts faithfully. Peter Lindert and Jeffrey Williamson argue that southern tax assessors systemically under reported the value of southern real estate, and they adjust their income estimates to account for the likelihood of corruption. This paper affirms the reliability of the tax returns by demonstrating that population density, rather than corruption or lax enforcement, can explain nearly all of the variation between the assessment districts. Accepting the tax valuations as accurate would lower Lindert and Williamson’s income estimates, imply slower growth rate between 1774 and 1800, and suggest a higher growth rate between 1800 and 1850.     

基于多源数据的兰州市主城区城市职住空间关系研究

随着中国经济转轨和社会转型，“职住分离”日趋严重，导致城市出现了一系列问题，急需对新的职住关系进行检视。职住关系研究的难点在于如何有效地锁定居住地、工作地，以及居民如何在居住地-工作地之间位移、居住-就业的空间匹配关系。论文以百度POI大数据和热力图为支撑，辅助问卷调查，结合兰州市土地利用现状图，综合应用职住比模型和最近距离等分析方法，多尺度刻画了兰州市主城区的职住关系。结果表明：在城区尺度上，兰州市职住关系总体处于平衡状态，职住平衡型占99.40%，居住倾向型和就业倾向型分别仅占0.12%和0.48%。从城市核心区到边缘区，职住失衡逐渐加重。职住平衡更多地体现在单位型社区上，失衡主要由商业型社区引致。在街道尺度上，职住关系差异明显，绝大多数街道处于职住平衡状态。城市核心区街道以“就业倾向型”为主；边缘区街道表现为“居住倾向型”。     

基于腾讯迁徙大数据的长三角城市群春运人口流动时空特征

开展城市群人口流动研究对促进区域人口有序流动和城市群协同发展具有重要的理论和实践指导意义。本文基于腾讯迁徙大数据，运用GIS空间统计和K-shell分解等方法，从人口流动总量、位序、时序和网络层级等方面，对我国长三角城市群2018年春运期间的人口流动特征进行系统研究。结果表明：①长三角城市群春运期间大规模的“返乡流”和“返城流”呈现明显的对称性，并分别于除夕和第一个工作日达到最高峰。②经济发展水平相对较高的上海、苏州、杭州等为劳动力输入型城市，而经济发展水平相对较低的盐城、安庆和滁州等为劳动力输出型城市。③长三角城市群内部人口流动网络具有明显的层级特征，其中上海和杭州是人口辐射核心城市，上海-合肥、上海-南京、上海-杭州等是人口流动的主体路径；空间上东部-西部横向人口流动最为频繁，大体呈现“Z”字形。     

RAPID REGIONAL ENLARGEMENT IN SWEDEN: A PHENOMENON MISSING AN EXPLANATION

According to Swedish register data, regional size and the extent of commuting have both increased rapidly in recent decades. From the perspective of policy-making authorities, this would indicate good prospects for regional development, as small regions could be integrated into larger ones resulting in increased economic growth. However, there are few concrete manifestations of such regional enlargement, and alternative datasets give other impressions of the effects of commuting. Here we argue that this apparent growth might stem from several problems inherent in a register-based way of measuring changes in commuting patterns. Thus, regional enlargement and the extent of commuting may be exaggerated when measured conventionally, and the high hopes of using such enlargement to lever regional development might be misplaced. More generally, this study considers the problems arising as census or other enquiry and interview based data are replaced by register data.     

Engaging children to voice their sense of place through location-based story making with photo-story maps

ABSTRACT

Sense of place is neither linear nor rooted in time. One way for children to voice their sense of place is through location-based stories with plots structured in space, rather than time. Since mobile devices are already ingrained in the everyday lives of many children in the U.S., a mobile application offers a familiar medium to engage children in location-based story making. Here, we present photo-story maps, our approach to leveraging an existing story-map mobile application as a research tool to collect and analyze children’s stories about sense of place. We found that photo-story maps facilitate the organization of nonlinear location-based stories, promote an inclusive story-making process through a mobile application, support triangulation of varied digital story elements, and provide dynamic interview material. We suggest photo-story maps demonstrate the value of location-based story making and the potential of familiar mobile applications for reducing the barriers to including children in research.     

Active use of panoramic mobile mapping systems for as built surveying and heritage documentation

Mobile mapping systems (MMS) are widely used technology nowadays for spatial data collection of large scale projects like for city and highway mapping. The systems are mainly equipped with laser scanning sensors and/or imaging sensors mounted on a moving vehicle during the scene capture. Imaging sensors are normally cameras which either capture perspective or panoramic images covering the whole horizon of the vehicle. The orientation of the captured panoramic images is accurate to centimeters’ level because of the precise positioning and navigation systems equipped with these mapping systems. However, the positioning accuracy of mobile mapping systems can be degraded in city centers or urban canyons because of the satellite signal disturbances.

In this article, we discuss the following objectives: (1) the possibility to use the mobile mapping images for cultural heritage documentation and as built surveying and how accurate the mapping can be; (2) the concept of using the mobile mapping images as a tool of georeferencing the crowdsource images; and (3) the efficiency of using the multi-temporal mobile mapping images for occluded free cultural heritage facade orthophotos. The mobile mapping systems of CycloMedia with two panoramic products of Cyclorama images (12 MP) and HD Cycloramas (100 MP) are used for the experimental tests in this research article.     

THE VIRTUALIZATION OF URBAN YOUNG PEOPLE'S MOBILITY PRACTICES: A TIME‐GEOGRAPHIC TYPOLOGY

A time‐geographic approach, including time–space diaries and in‐depth interviews, is used to investigate the daily use and implications of information and communication technologies (ICTs) among a group of Swedish urban youth. We identify individual variations and nuances in ICT‐based practices in our respondents' social and spatial contexts. Using individual cases and detailed time‐geographic trajectories, we demonstrate how daily communicative actions – physical and virtual – are combined and integrated. From this we identify four ideal types of mobility practices: (i) home‐oriented, heavy Internet users; (ii) physically mobile, heavy mobile phone users; (iii) physically mobile, heavy Internet and mobile phone users; and (iv) home‐oriented, rarely mobile people (virtually and physically).