基于距离测度方法的犯罪活动与城市功能分布关系研究

Exploring distribution relationship between criminal activities and urban functions using distance-based methods

基于面域汇总数据的犯罪地理分析不仅存在MAUP局限,还会制约理论发展。本文将基于距离测度方法的DO指数用于犯罪地理研究,在连续空间上揭示2013—2018年北京盗窃、抢夺抢劫、暴力犯罪与32类城市功能的分布关系。研究表明:①98%的"犯罪-功能"组合呈共聚分布,单一尺度分析极易低估犯罪发生地的种类数;②由于罪犯在中等尺度上选择收益、风险、成本适中的概率最高,"犯罪-功能"组合的共聚尺度与程度多为倒U型关系,该规律有助补足日常活动理论和理性选择理论的空间视角;③随着监管加强,三种犯罪与所有功能的总体共聚程度渐趋下降,暴力犯罪的共聚尺度大于"两抢一盗";④较之犯罪模式理论中的单一共聚类型,共聚组合可细分成大、中、小尺度强共聚型以及弱共聚型等小类。本研究将犯罪空间形成机制简化为犯罪点与功能点的几何关系,未来需克服混淆因素干扰、功能点均质化假设等。

Existing criminal geographical research mainly relies on cluster-based methods and aggregated data according to pre-defined geographic limits, which not only causes modifiable areal unit problem, but also restricts the development of classical criminal geography theory.Consequently, this paper pioneered the use of DO index, a new distance-based method, to Chinese criminal geographical research, in order to reveal the spatial distribution relationship between theft, robbery, violent crime and 32 main urban functions in continuous space of Beijing from 2013 to 2018. Firstly, the research demonstrated that even distribution of economic and social activities was controlled, 98% of the"crime-function"combinations were significantly colocalized. The traditional method judging merely on a single spatial scale would probably underestimate the number of types of crime generators. Secondly, most pairs of"crime-function"combinations inverted U-shaped relationships between the scale and degree of colocalization, because criminals were more likely to choose medium returns, risks, and costs in the medium spatial scale. This finding made up the spatial perspective blind spot of routine activity theory and rational choice theory. Thirdly, with improvement of supervision intensity, the degree of colocalization between crimes and all urban functions were gradually decreasing. Owing to obvious ways of committing crimes and higher capture probability, the colocalization spatial scale of violent crime was greater than that of theft or robbery. Fourthly,compared with single colocalization type in existing criminal pattern theory, there were many sub-types such as strong colocalization in large, medium, small spatial scales and weak colocalization, which showed the necessity of subdivisions of crime generators. All in all,nearly half of the"crime-function"combinations have always belonged to the same subgroup,which proves that the crime prevention and control work is evidence-based. Limited resources should be given priority to bus stations, arterial road junctions, foreign-related sites, high-end communities, and factories. Additionally, for the crime prevention work, it is important to formulate specific measures according to the type of crime generators, and break through traditional control concepts of fixed points and fixed jurisdictions. All in all, this study simplified the complex crime space formation mechanism into the geometric relationship between crime points and function points. It should be pointed out that the distance-based method was difficult to control the interference of confounding factors and needed to be addressed in future research.