| Human settlements refer to the space where human beings congregate on the surface of the earth,including climate environment,ecological environment,urban construction environment and so on.In the urbanization era,the human settlements are greatly affected.The construction of infrastructure improves the liveability of human settlements,but at the same time causes problems such as aggravated urban heat island phenomenon and reducing the visibility of urban green space,which threatens the health of urban residents and reduces the liveability of the city.How to keep protecting ecological environment as well as the quality of residents' life in the process of urban development remains a huge challenge for urban planning.Building a livable city with high-standard human settlements environment is the primary goal of all countries in the world,and one of the main goals of sustainable development proposed by the United Nations.Current researchers mainly do research in two-dimensional space.The information in three-dimensional information is rarely considered.However,as economic develops with population growth,the urbanization process has been rapid.Urban form has been expanded both horizontally and vertically,which influences the human settlements directly or indirectly.Thus,this research takes the region enclosed by the outmost belt road in Shanghai as the study area and anlalyzes the urban human settlements in three-dimensional space,mainly,a)the impact of three-dimensional urban morphology on thermal environment;and b)the three-dimensional evaluation of human settlement environment.The main research contents and achievements of this paper can be summarized as follows:(1)The effect of three-dimensional landscape pattern on urban thermal environment is analyzed.Firstly,a set of two-dimensional and three-dimensional landscape pattern metrics were calculated to quantitatively describe the urban landscape pattern.Then,several eXtreme Gradient Boosting(XGBoost)models were established in the study area within the outer ring of Shanghai City using landscape pattern metrics as variables,land surface temperature(LST)being the target.The fine-scale relationship between 3D landscape pattern and LST was then explored.Furthermore,the Shapley Additive exPlanations(SHAP)method is used to interpret the influence of three-dimensional landscape metrics on LST.The results show that three-dimensional urban landscape metrics can explain up to 75.7% of the LST variations,which is 12.1% higher than the traditional 2D model.Based on the analysis of different urban functional zones,the different effects of three-dimensional landscape pattern on LST were revealed.The thermal environment in built-up areas is greatly influenced by the roughness of the ground surface due to the existence of large amount of man-made landscapes.The elevation of buildings greatly affects the thermal environment in industrial area,while residential and public management and service lands are more influenced by the volume of vegetation.As for the two major landscape elements that have three-dimensional properties,buildings above 30 m or below 10 m can alleviate the urban heat island effect while the middle-rise buildings show obvious warming effect.The UHI mitigation role of vegetation is still valid in a 3D metrics system-a larger proportion of vegetation in 3D space showed a greater cooling effect on LST.3D landscape design of vegetation could have major contribution to reducing UHI.(2)The visual amenity of green space in 3D space is evaluated via a newly proposed indicator called Floor Green View Index(FGVI),which is designed for quantifying visual amenity of urban vegetation on different floor heights.The method is proposed and tested via a case study of the Lujiazui region using airborne Light Detection and Ranging(LiDAR)data and aerial photographs.The results show that the FGVI effectively represents 6-story residential buildings' poor view of public greenery,while the white-collar workers in commercial built-ups and people living in upper floors visually enjoy a higher amount of visible greenery out of their windows.Besides,in the simulated urban renewal program of constructing a new high-rise commercial structure near residential buildings,FGVI successfully monitored its impact on the visual amenity of the neighborhood.Therefore,the new indicator and methods can be used as powerful quantitative tools for urban design,landscape architecture,urban green planning and management,with social benefits and economic value.(3)The liveability of human settlements is evaluated in 3D space.A three-dimensional evaluation system is proposed considering both physical and mental environment of human settlements.Based on the multi-source data,all the evaluation metrics are extracted via remote sensing and GIS methods.The region enclosed by the outmost belt road in Shanghai was selected as the study area,upon which residential parcel-level and floor-level evaluations were carried out respectively.The results show that the most livable residential lots are concentrated in the southwest to northwest part between the inner and outer ring,which has a good urban development system and ecological environment.The least livable areas are mainly old residential areas within the inner ring and the natural villages along the outer ring--the former restricted by poor ecological environment,the latter by the urban development system.As for floor-level results in Lujiazui region,several rules can be concluded: the liveability of top floors is better than that of lower floors;the liveability of residential buildings along the river is higher;and the liveability of the street residential buildings is worse than the central ones in the same residential lot.The low-cost,multilevel,multi-dimension and high-efficiency liveability evaluation system can provide insights for urban designers and decision makers when improving public facilities,medical and health care,basic education and residents' living comfort. |
PDF Full Text Request