Examining The Functional Density And Diversity Of Traditional Blocks Of Guangzhou In The View Of Urbanity

The city as an important place for people to gather has some features distinct from the country,referred to as urbanism.As Wirth put forward in his classical treatise,urbanity originates from population size,density and heterogeneity(Wirth,1938).Jacobs also made mention of the high density,diversity and functional combination of urbanity in his theory of urban diversity.It is well known that the city is full of vitality because of the existence of urbanity.However,continuous renewal and reconstruction of old cities in recent years has caused some certain negative impacts on the density and diversity of the old cities,which has damaged the urban features and urban vitality.Under the background of information age,how to study the diversity and density of the old city,and how to avoid the use of quantitative description to present the characteristics of the research object in previous urban studies,should be a concern that has to be paid much attention to at this stage.In this paper,old city blocks in Guangzhou are taken as the research object and an empirical research of the functional density and diversity of these blocks are carried out by using new data after reviewing relevant theories and research methods.Considering that the general elements of block are indispensable base in block research,it is included in this empirical study also.In the relevant theories and research sections,the search closely related to the general elements of block including urban morphology,traffic accessibility,and the function density and diversity from the urbanity perspective are comprehensively reviewed and analyzed.In empirical research section,based on the collected new data from Dianping.com,Gaode map vector data and others,old city blocks in Guangzhou are deeply studied as follow: 1)Based on the building outline,height data and actual traffic time consuming data of Gaode map and the POI data of Dianping.com,the characteristics of general block elements are studied from three aspects of urban form,traffic accessibility,historical and cultural value of blocks;2)Based on the POI data of Dianping.com,the function density and diversity of the blocks are measured by means of Shannon diversity index,spatial autocorrelation and other analytical methods;3)Starting from the general elements that constitute the block,this paper makes a preliminary exploration of the formation mechanism of the functional density and diversity of the block by using correlation analysis.According to the analysis results of data,it is found that the old city blocks with larger functional density in Guangzhou mainly focus on the trading areas of Beijing road,Shangxiajiu and Jiangnan west,reflecting the radiation effect of urban commercial center towards surrounding area,Moreover,more than 50% of the blocks show a feature that the external spatial function density is greater than the internal.In terms of functional diversity,the diversity index of blocks are high overall and largely distributed in government agencies,unit compounds,subway stations,main city roads(inner ring road,Zhongshan road,Jiangnan west road,etc.),as well as the areas with abundant landscape resources;In the analysis of block function and general elements,the function density and diversity of blocks are linearly positive with the average height and volume rate of block buildings,but the correlation degree is not strong.It is important to note that the diversity of most blocks with smaller scale or rich historical buildings is not high,contrary to some general peripheral blocks with larger scale which have higher diversity.This result is somewhat discrepant to Jacobs' opinion about the conditions to maintain the urban diversity.The reason may be that the block sizes are too small or the protection of historical style and features limits the setting of certain functional facilities,and further affect the diversity.At the same time,the classification is set mainly according to major categories,and the incomplete analysis of historical and cultural values will also bring errors to the diversity research results.In sum,using new data to quantitatively measure the functional density and diversity of the old city blocks in Guangzhou from the perspective of urbanism,can not only objectively reflect the urbanism of old city blocks,but also provides a new perspective for people to scientifically and accurately understand the characteristics of old city blocks.