CGA Seminar Series:GIS Applications in China Studies 2013.9.27 Xin LAO 劳昕 Doctoral candidate of Regional Economics Peking University, China (1) 人口迁移已成为中国城市化研究中的重要问题 Migration:An important issue in China’s urbanization research 中国的城市化首先表现为人口城市化,而中国目前的城镇人口增长除了自然增长 以外,主要来源于农村人口向城镇的迁移,“候鸟型”流动人口与“定居型” 流动人口将长期并存。 (2) 城市网络研究已成为城市体系研究的新范式 Urban network research:New paradigm of the research on urban system (3)社会网络分析方法已成为研究区域与城市问题的新方法 Network analysis method:New Method of researching regional and urban issues 随着城市空间的网络化发展,城市之间的联系日益密切,社会网络分析 方法可作为城市之间关系的分析工具,且此方法也适用于国家层次 或者区域层次城市之间的关系研究。 研究问题的提出 The research question 城市化将成为主导中国未来经济发展的最主要的趋势,而城市化最 直接、最明显的表现就是人口在不同空间区位上的重新聚集和分布, 即人口迁移,导致了城市体系的演化。 Migration leads to the changes of urban system 人口迁移与城市的关系和网络流量与节点的关系具有很大的相似性, 人口迁移与城市之间构成了复杂的网络关系。 The relationship between migration and cities is similar to the relationship between network flow and nodes 目前国内外用网络分析方法来研究城市体系演化多从经济网络和基 础设施网络(含交通网络和互联网)角度入手,未能抓住中国城市 网络体系演化的本质,而中国的人口迁移研究也多停留在省级层面 上。本研究将从城市化的本质——人口迁移网络出发,基于中国各 城市间人口迁移来预测中国未来城市体系的演化,用网络研究方法 分析城市人口迁移的空间特性,探讨中国城市体系演化机理,从而 推进中国城市化研究。 It is possible to predict the urban system evolution based on inter-city migration 1 城市体系研究 Urban system research 传统的城市体系研究(规模结构、等级结构、空间结构)静态和属性 的研究范式——基于网络的城市体系研究:动态和关联的新研究范式 Traditional urban system research(size, rank and spatial structures):static and attribute-based——New urban system research based on network: dynamic and interrelated (1)中国城市规模分布实证研究 City size distribution (Traditional) (2)中国城市体系的空间网络结构 Spatial network structure (New) 2 人口空间分布与迁移研究 Population distribution and migration research (1)中国人口分布变化特征 Population distribution change (2)中国人口迁移特征分析 Migration characteristics 1 城市体系研究 Urban system research (1)中国城市规模分布实证研究 City size distribution Abstract: Zipf’s Law is an important principle to determine city agglomeration and urban system rationality, which reflects the simple and accurate relationship between city size and its rank. Since the definition of cities in Zipf’s Law have roused much controversy due to the too macro spatial scale that cannot exactly reflect the actual city size, scholars have moved on to the functional city cluster at the micro level, which breaks the traditional administrative boundaries. Based on the second national census data at the micro level (townships and streets) , this article creatively uses functional city clusters processed with City Clustering Algorithm (Rozenfeld et al., 2011) as research objects, and then analyzes China’s city size distribution according to Zipf’s Law. The results indicate that China’s city size distribution basically obeys Zipf’s Law. Furthermore, by comparing the city size distribution results based on City Clustering Algorithm and the results at the spatial levels of prefectures, counties, townships and streets, it has been proved that City Clustering Algorithm, as a new method to research the city size distribution, has a good prospect of application, that is, building a bridge between research at the macro and micro level. Zipf’s Law: 1 城市体系研究 Urban system research (1)中国城市规模分布实证研究 City size distribution 主要研究方法 Main research method 城 市 聚 类 算 法 中国的城市聚类算法结果图 不同距离阈值ℓ下的 城市组团人口概率分布图 1 城市体系研究 Urban system research (2)中国城市体系的空间网络结构 Spatial network structure Abstract: The research on the urban system has been a traditional issue in the fields of urban geography and regional economics. The relationship among cities in the urban system not only exists in the form of rank, but also in a more general form of network. Based on the research on the spatial structure of China’s urban system in terms of transportation network and economic network, this article analyzed and revealed the spatial structure features of China’s urban system by comparing these two kinds of urban network, thus providing new ideas for the research on China’s urban network. The results indicated that China had formed a basic triangle framework of urban network with Beijing, Shanghai and Guangzhou as cores, and there existed a layer structure decreasing outward from national centers in the spatial connections among cities. More importantly, it is found out that the transportation network contributes to the balanced regional development, while the economic network promotes the agglomeration economy. By combining both together, we can provide abundant theoretical foundation for promoting China’s balanced economic development under the condition of agglomeration. 1 城市体系研究 Urban system research (2)中国城市体系的空间网络结构 Spatial network structure 主要研究方法 Main research method Transportation Network: Aviation flow Economic Network: Urban flow and Gravity & Potential model The aviation network among China’s 15 major cities in 2010 The structure of urban flows of China’s major cities in 2010 2人口空间分布与迁移研究 Population distribution and migration research (Based on the six national census data(2010)) (1)中国人口分布变化特征 Population distribution change 人口规模变化 Population size change 人口密度变化 Population density change 人口重心与展布范围变化 Population gravity center and distribution range change 人口分布空间自相关性变化 population spatial autocorrelation change 2人口空间分布与迁移研究 Population distribution and migration research (Based on the six national census data(2010)) (1)中国人口分布变化特征 Population distribution change size Gravity center Standard Deviation Ellipse density Moran’s I 2 人口空间分布与迁移研究 Population distribution and migration research (Based on the six national census data(2010)) (1)中国人口分布变化特征 Population distribution change 基本结论 Basic Results ①我国人口分布模式:瑷珲-腾冲一线从提出到现在基本未变,总体来看东南地区人口密集, 西北地区人口稀疏,并呈现出东南地区密中有疏、西北地区疏中有密的特点。 Dense in southeast and sparse in northwest ②2000-2010年我国的人口变动模式:在省间人口迁移明显,主要从中西部省份流向东部 省份;在市间也存在一定程度人口迁移,但不如在省间流动显著。 Significant Migration from middle and west to east ③人口迁移对我国人口分布影响在加大,影响方向向东移动。 Migration impacts the population distribution to the east ④我国人口分布存在一定的空间自相关性。随着时间的推移,在省间和县间,这种自相关 性在增强。在市间,这种自相关性在减弱。说明我国人口分布在省间和县间的集 聚性在增强,在市间人口集聚性在减弱。There exists spatial autocorrelation in population distribution 2 人口空间分布与迁移研究 Population distribution change (Based on the six national census data(2010)) (2)中国人口迁移特征分析 Migration characteristics 主要研究方法 Main research method Inter-province migration Typical destination: Shanghai Typical origin: Sichuan Migration network 2 人口空间分布与迁移研究 Population distribution change (2)中国人口迁移特征分析 Migration characteristics 省际人口迁移特征 Overall migration characteristics 主要迁入地分析 Main area of destination 主要迁出地分析 Main area of origin 人口迁移网络分析 Migration network analysis (Based on the six national census data(2010)) 基本结论:我国省际人口迁移活跃(迁入量、迁出量较高)的区域分布在南方 和沿海地区。主要人口迁入地分布在沿海地区,具体为上海、北京、广东、浙 江、江苏;主要人口迁出地分布在秦岭-淮河以南的中部省份,具体为四川、 河南、安徽、湖北、湖南;主要迁入地和迁出地网络度中心性最高 Basic results: active migration regions——southern and coastal China; main areas of destination——coastal China; main areas of origin——central China south of Qinling Mountain and Huaihe River; areas of high network degree centrality: main areas of destination and origin 传统人口预测模型:以单个封闭区域为研究对象,忽略城市间的人口 迁移流对各城市人口规模变化的影响,忽略了各城市是处于一个动态 的、相互联系的城市网络中的,没有预测整个城市体系中相互联系的 各个城市的人口是如何变化的 Combine the above two researches (urban system and migration) together and establish a new population prediction model: predict the population change in each city within the dynamic, interrelated urban network, regarding the urban system as a whole——predict the urban system evolution based on the inter-city migration network 本研究将构建新的人口预测模型,基于各城市间人口迁移来预测整个 城市体系中各个城市人口的变化 (1)分析人口迁移网络特征,通过经验数据(普查和调查数据)及国家未来政策趋 势总结出人口迁移分布规律 Sum up migration laws based on empirical data (2)在人口迁移分布规律基础上构建不同的城市化情景(不同城市化速度、大城市导 向、小城市导向等),将城市间的迁移率分成特定的几类,构建迁移模型(迁移矩 阵):关于出生率、死亡率、迁移率等变量的各城市人口函数,若干约束条件(人口 承载力、总和生育率、人口总数、迁移人口总数等)Establish migration model assuming different scenarios and different migration rates (3)在构建的城市人口迁移网络基础上求解、探索中国未来城市人口空间分布 Predict China’s future population distribution (4)进一步分析中国城市体系演化机理 Analyze the mechanism of urban system evolution 需要解决的问题 Problems to solve 人口迁移数据的获取:人口普查数据、统计年鉴、社会调查数据、研究报 告——城市间人口迁移数据? The difficulty in obtaining micro-level migration data (i.e., intercity migration): A model must be built based on empirical data and several assumptions 如何将多区域人口模型拓展到复杂的空间层面(287*287矩阵)? Andrei Rogers(1979): Multiregional Methods for Subnational Population Projections(mainly two regions: urban and rural area)— —How to spatialize (287*287 matrix)? 如何构建不同的城市化情景,设定几类不同的迁移率?(大城市 、中等城 市、小城市间) How to assume several types of urbanization scenarios and migration rate (Among big cities, middle cities and small cities)?