The Study Of Quantification Method On Urban Greenspace Configuration

The scientific configuration of urban greenspace has important theoretical and practical significance for intensive use of land and optimizing urban living environment. In order to improve the quality of urban environment and save land resources, the paper studies the scientific quantitative method of urban greenspace configuration. The research could be used as reference for the urban planning, as well as consultation for management and control of governors.Paper presents a new multi-levels quantification research system of urban greenspace. The new system abandons the shortage of traditional study of urban greenspace research that paid attention to the whole, as well as ignored the individuals. The new system will focus on the green block with the specific shape, size and location, and examine the greenspace in itself and the relationship between the greenspace and the surrounding environment with scientific method.In this perspective, the greenspace is no longer just an ecological concept, but a kind of landuse with different function according to different locations in the city. Urban Greenspace is affected by the nature of the surrounding land area, population, traffic conditions and other objective factors. Meanwhile, the Greenspace affects the surrounding area with the provision of open space, improving the micro climate and environmental quality. And different functions require the different structural layout of the greenspace, including the proportion and structure of grass, bushes, trees and the distribution of buildings. All of these construct a mixed urban environment with interactive systems. Studies of urban greenspace must be conducted in such a system to guarantee the scientificity of the research and the effectiveness of the results.Based on the new research system, paper presents some new concepts from three levels which include the relationship between the greenspace and the pattern of urban landuse, the distribution pattern of the greenspace, and the characteristics of the greenspace.1. Paper reclassifies the greenspace into two categories-"mandatory green" and "non-mandatory green" by the requirements of urban environmental quality, abandoning the traditional classification with function. The mandatory green is the basic security of the urban environment. It there was a shortage of the mandatory green, the quality of urban environment would be damaged. Mandatory green's location, size and shape are generally limited to specific requirements.2. Paper re-examines and quantifies the location difference of greenspace in order to directly reflect the scope of influence of greenspace. The location difference of greenspace gave rise to the dynamic of the percentage of use. The rationalized application of location difference and percentage of use could enhance the utilization efficiency of greenspace and avoid the waste of land resources.3. Paper sets up the quantitative indexes system to describe the quality of greensapce, including green rate, green coverage ratio and green area ratio. The quantitative indexes system not only can accurately describe the layout structure of greenspace, but also can reflect the structural features in three dimensions. The threshold of the index integrates the absorption capacity of carbon dioxide of vegetation in order to maintain the quality of its environment protection effect.4. Paper proposes the index of distribution of buildings in greenspace. The index can be used to describe the various distribution from disperse to cluster. Through the reasonable value of the index, urban governors can control the buildings layout in the greenspace.Based on GIS, paper built a database with data of regulatory plan of the city, and applied many kinds of spatial analysis technologies. On this basis, paper constructed a series of mathematical models and parametrical models to test and verify those new concepts. The models include:1. the generative model of mandatory green buffer, which is with the provision of the input data of landuse, transportation networks and infrastructure and the parametric value of relevant laws; 2. the computation model of dynamic percentage of use of greenspace, which is with the provision of the green area ratio in every calculation unit; 3. the generative model of the layout of greenspace based on the quantitative indexes system for describing the quality of greenspace; 4. the generative model of the layout of buildings based on the index of distribution of buildings in the greenspace.