面向精细化的尺度选择——城市形态微观要素界定中的非定值缓冲法

Toward Delicate Scale Selection:Non-fixed Value Buffer Method in the Definition of Micro Morphological Elements of Urban Form

在城市形态量化研究中,对所研究的形态要素进行界定是研究的第一步。就城市形态微观要素而言,既有像街区和地块这样有较为清晰边界线的要素,其对象能够被直接定义;也有诸如街道和街口等要素,对其三维形态的界定则相对模糊——对于后者的精细化界定是本文所关注的问题。本文首先对既有研究中定值缓冲法进行回顾与反思;再从理论层面对诸如街道、街口等特定微观要素的三维形态进行解构与辨析,将其拆解成由核心开敞空间与建成实体空间所构成的整体;同时,提出一套数字化的技术流程,先后对形态要素的核心开敞空间与建成实体空间进行尺度测度,以完成整体形态要素的对象界定,即“非定值缓冲法”。面向精细化的尺度选择是城市形态量化研究走向精细化的前置性步骤,具有牵一发而动全身的全局效应。本文结合具体城市案例的实证研究进行了阐述。

The first step in quantitative studies of urban form is to define the morphological elements.As far as the micro elements of urban form are concerned,there are elements with clear boundaries,such as blocks and plots,which can be defined directly.At the same time,there are also elements,such as streets and intersections,with relatively vague boundaries and definitions.How to define these elements is the focus of this paper.Based on the review of the fixed value buffer method in the existing research,this paper deconstructs and discriminates the threedimensional form of specific micro elements such as streets and intersections from the theoretical level,thus disassembling it into an entity of void and mass.At the same time,a set of digital technical process is proposed to measure the void and mass,in order to provide a delicate object definition.The proposed method is named non-fixed value buffer method.A delicate scale selection of morphological elements is a pre step for the refinement of quantitative research on urban form,which plays a crucial role in the analytical process.This paper further elaborates it through the empirical study of specific urban cases.