Research On Extraction Of Urban Spatial Pattern Elements And Structure Model Based On Land-Use Data

The urban spatial pattern is the skeleton of urban development,which guides the function construction of the city,and therefore affects the comprehensive sustainable development of the city.With the accelerating development of urbanization in China,many cities are faced with the historic opportunity of spatial reconstruction andadjustment.For a city in upheaval,its urban spatial pattern must be at dynamic change and migration,and the main trend and future direction of urban development can be learned when we observe the evolution of urban pattern from a macro perspective.Urban spatial pattern tends to have periodicity in planning and design,reflected in a blueprint for the future development.Although unorthodox,the status structure(i.e.,urban spatial patterns at a certain time during the planning period)are significantly important to policymakers and urban planning.Status structure not only provide the methodological foundation of urban spatial pattern evolution for comparative and quantitative analysis between existing and planned conditions,but also lay a theoretical basis for failure in scientific decision making during the planning phase.Then,can an urban spatial pattern be analysed in the context of the status of a city to understand the status and trend of urban development?Urban spatial pattern is the skeleton of urban development,which reflects spatial layouts based on the different composition of certain features through the synthesis and abstraction.Many works have been proposed for identifying the elements of urban spatial pattern.We divide these studies into two main approaches,namely,empirical and model-based method.However,the first has difficulties in obtaining data,and the second is not sufficiently convincing in various dimensions,such as identification rules and applicability of the methods.Thus,how can we effectively and accurately extract these elements?The layout models that elements form in the urban space are regular,then what are the pattern models?The traditional studies on the pattern models only focus on the reaserch of qualitative induction,lack the methodological foundation of pattern model recognition and expression.The research of these issues can hopefully establish a new methodology for urban spatial pattern.To adreess the above issues,this reaserch analyzes the urban spatial pattern by excavating the urban spatial pattern rules hiding in the land use data fully,takes“Feature Analysis”-“Element Extraction”-“Pattern Study”as the main clue of the research,uses spatial data mining to identify and extract the element of urban spatial pattern,and explores the pattern model formed by empirical and model methods.This research is conduted from the following four aspectes:(1)Urban spatial pattern and its element featuresFirstly,this paper proposes the concept and basic characteristics of urban spatial pattern by discriminating related conceptions and considering the research data.Secondly,this paper defines the urban center,urban axis,urban group,urban contour and urban road skeleton as the typical depiction elements of urban spatial pattern from the perspectives of the element property and scale characteristic.Finally,this paper studies the characteristics of the concept,geometry and attributes of pattern elements and analyzes the correlation characteristics among elements and between elments and urban land use.The reaserch of urban spatial pattern and its element features not only provides a useful exploration for the spatial pattern of urban scale,but also establishes theoretical base for the identification and extraction of pattern elements.(2)Identification and extraction of urban spatial pattern elements based on urban land useBy analyzing the existed methods for extracting pattern elements,and taking element characteristics into account,this paper respectively proposes the method for the extraction of based on graph theory and information entropy,method for the extraction of urban group based on field theory's spatial cluster algorithm,method for the extraction of urban contour based on the shape reconstruction from planar point set,method for the extraction of urban axis based on the main skeleton line of area features,method for the extraction of urban road skeleton based on Stroke model and complex network analysis.The effectiveness and validity of our algorithms are verified using simulated or real spatial datasets.(3)Research method for urban spatial pattern models combined with empirical law and modellingFirstly,this paper establishes several typical models of urban spatial pattern in China,including ribbon-like,group-like,radial form,ring-like and skip form,and analyes the characteristics of elements in each model.Secondly,taking pattern elements as unit,this paper respectively proposes the measurement method for urban centre based on automatic classification,measurement method for urban group and axis based on spatial relationship,measurement method for urban contour and road skeleton based on geometrical structure.These measurement methods can constitute as the recognition rules for pattern models.Finally,this paper adopts symbolic operationa and map generalization algorithms to achieve the visualization for intention map of urban spatial pattern.(4)Research on the extraction of features of urban spatial pattern and its structure modelThe research on extraction of urban spatial pattern elements and pattern model is experimented based on urban land use data in different cities,and the comparison between experimental results and the comprehensive plan achievements of corresponding cities is conduted.The experimental results verify the accuracy of our extraction methods for pattern elments and measurement methods for pattern models,on the other hand,validate the practicality of our research,which is indicated by providing the comparative and quantitative analysis between existing conditions and planning.