City Block Index Expression Method Research Base On Facade Outline

The city’s "two-dimensional index" and "three-dimensional shape" exist a close relationship, and the urban spatial form shaping is one of the main tasks of urban design. Therefore, the shaping of city’s three-dimensional needs the urban index, so that the intrinsic relationship between the city’s "two-dimensional metrics" and "three-dimensional shape" is very important to architect.Nowadays, regulatory plan is the main theoretical basis for guiding the management of urban construction, it mainly with control by index system on two aspects:the land use and urban space. However, the current regulatory plan mainly focus on the land use. It causes the neglect of control and guidance in the urban space environment, which leads to the city’s public space in appearance of chaos. In contrast to it’s reasons, regulatory plan indicators and urban spatial form are not the one to one relationship, but one to many relationship, that is an indicator system can correspond to a variety of spatial forms.Therefore, in the essay, block facade outline of urban public space is the start point, though the block facade outline to analysis the relationship of regulatory plan index and block facade morphological parameters. Through the construction and research of the ideal model for different types of block (homogeneous block, level block, holes block), the essay put forward the method for calculating the block index through the block facade outline and verified by actual blocks.But due to the impact of that simplified models, in dealing with the reality of blocks, there are some limitations based on research models deduced calculated. The essay has been amended in accordance with the actual situation of the reality blocks so that it can accommodate more blocks.The result show that the calculation method has been improved can be better applied to homogeneous blocks, parts of level blocks and parts of holes blocks. However there are some blocks still can not use this method to calculate the block index. In addition, experiment with different scale blocks, we found that the perimeter of blocks between 600-1200M has the smallest error between actual and calculate.