This study proposes a refined methodology for controlling building heights in heritage areas.In order to protect the visual integrity of the heritage area,buildings should not obstruct the view from important site poi...This study proposes a refined methodology for controlling building heights in heritage areas.In order to protect the visual integrity of the heritage area,buildings should not obstruct the view from important site points and viewpoints to the periphery.By calculating the building height thresholds that buildings should not obscure the view from each viewpoint,the results of which are weighted and superimposed,and the values are extracted to each building unit as a refined building height control guideline.This study takes the Zhoukoudian area as a case study,applies the refined building height control criterion to the Zhoukoudian Site,and relies on this refined criterion to assess the visual integrity of the Zhoukoudian area,so as to realize the scientific planning and monitoring of the Zhoukoudian area.The refined building height control method can be applied to building height planning and visual landscape protection in large heritage areas.展开更多
Understanding the spatiotemporal patterns of three-dimensional urban forms,especially building height,can have important implications for improving urban air quality and mitigating the urban heat island effect by opti...Understanding the spatiotemporal patterns of three-dimensional urban forms,especially building height,can have important implications for improving urban air quality and mitigating the urban heat island effect by optimizing urban planning and management policies.This study investigated building height evolution and its influencing factors over approximately half a century(1960–2017)in Guangzhou,China.The results indicated that the logarithmic declines in height,quantity,and area of urban buildings followed Zapf’s law,which restricts the three-dimensional shape of the urban form.The urban building height decreased from the center to the periphery of the city and decreased with decreasing altitude and increasing distance from main roads.These characteristics constituted the three main spatial differentiation rules of building height in the central district of Guangzhou,and all exhibited a logarithmic decrease,which gradually strengthened over time.The development of a double-layered height structure of low-rise and high-rise buildings between 1990 and 2017 was a notable manifestation of the increase in vertical urban height over time.The three factors of city center,altitude,and accessibility,which represent centrality,low relief,proximity to water,and proximity to road networks,highlighted the roles of traffic accessibility and commercial attraction in building height evolution.The importance of location macroscopically depends on the combined effect of the geographical pattern,urban planning,and market forces of cities located on a plain near hill or by a river.The principle of profit orientation restricted spatiotemporal building height patterns.展开更多
Building geometry data is crucial for detailed, spatially-explicit analyses of the building stock in energy systems analysis and beyond. Despite the existence of diverse datasets and methods, a standardized and valida...Building geometry data is crucial for detailed, spatially-explicit analyses of the building stock in energy systems analysis and beyond. Despite the existence of diverse datasets and methods, a standardized and validated approach for creating a nation-wide unified and complete dataset of German building heights is not yet available. This study develops and validates such a methodology, combining different data sources for building footprints and heights and filling gaps in height data using an XGBoost machine learning algorithm. The XGBoost model achieves a mean absolute error of 1.78 m at the national level and between 1.52 m and 3.47 m at the federal state level. The goal is proving the applicability of the methodology at a large scale and creating a useful dataset. The resulting dataset is thoroughly evaluated on a building-by-building level and spatially resolved statistics on the quality of the dataset are reported. This detailed validation found that the building number and footprint area of German building stock is 90.31 % and 94.84 % correct, respectively, and the building height accuracy is 0.59 m at the national level. However, errors are not homogeneous across Germany and further research is needed into the impact of including additional datasets, especially for regions and building types with lower accuracies. This study proves that the chosen methodology is useful for generating a building height dataset and the workflow, with some modifications for regional data availability, can be transferred to other countries. The generated building dataset for Germany constitutes a valuable data basis for the research community in fields such as energy research, urban planning and building decarbonization policy development.展开更多
Rational urban design helps to build sustainable cities with high ventilation capacity and pollutant removal ca-pacity,but the effect of building height on ventilation and pollutant dispersion inside asymmetric canyon...Rational urban design helps to build sustainable cities with high ventilation capacity and pollutant removal ca-pacity,but the effect of building height on ventilation and pollutant dispersion inside asymmetric canyons has not been fully studied.In this paper,we studied the effect of increasing the degree of building height asym-metry(DBHA)on canyon ventilation and pollutant diffusion in shallow and deep asymmetric street canyons by considering six different building height ratios(BHR=3/4,1/2,1/3,4/3,2/1 and 3/1).The results show that increasing the DBHA in asymmetric canyons can improve the ventilation and pollutant removal capacity.For step-up canyons,increasing the downwind building height is very useful to improve ventilation and pollutant re-moval.For shallow/deep step-up canyons with BHR=1/3,the air exchange rate(ACH)increased to 211.2%and 380.1%of the flat canyons,respectively.The spatially-average pollutant concentration in the pedestrian zones(leeward Kavg∗ang windward Kavg∗)decreases significantly with the increase of DBHA,especially for the deep step-up canyon with BHR=1/3,the leeward Kavg∗and windward Kavg∗decrease to 15.3%and 3%,respectively.Also,increasing the upwind building height can also improve the ventilation capacity in the step-down canyons.For the deep step-down canyon with BHR=3/1,the leeward Kavg∗and windward Kavg∗decreased to 40.6%and 24.1%of the deep flat canyon,respectively.Notably,the ventilation capacity is very low for step-down canyons with BHR=4/3,and for step-down canyons with BHR≥2/1,the ventilation capacity and pollutant removal capacity increase significantly with the increase of DBHA.Therefore,in urban planning,step-down canyons with BHR=4/3 should be avoided and designed to satisfy the condition of BHR≥2/1.These findings will be a valuable reference for urban designers to build sustainable cities with high ventilation capacity.展开更多
As part of a broad strategy to reach net-zero greenhouse gas emissions and limit global warming,many countries are requiring all new buildings to have net-zero energy use.This requires that on-site energy use not exce...As part of a broad strategy to reach net-zero greenhouse gas emissions and limit global warming,many countries are requiring all new buildings to have net-zero energy use.This requires that on-site energy use not exceed on-site generation of renewable energy(taken here to be solar energy),or equivalently,that the building Energy Use Intensity(EUI,kWh/m^(2)a)not exceed the supply of on-site solar energy(electricity and heat)per m^(2)of floor area per year.On this basis,we find that achieving net-zero energy performance in an archetype 40-story square building in 16 different cities of North America requires EUI of 17–24 kWh/m^(2)a using PV panels,and 19–28 kWh/m^(2)a using PVT collectors.Changing building orientation to a non-square floor shape can improve maximum permitted EUI by up to 50%in PV and 60%in PVT case.Conversely,the best-performing residential and commercial buildings have EUIs of 50–75 kWh/m^(2)a.Only if building heights are limited to 5–10 floors does the available solar energy,and thus the permitted EUI,reach 50–75 kWh/m^(2)a.Therefore,we recommend that policymakers not require high-rise buildings to be net-zero energy,unless they are prepared to limit building heights to 5–10 floors.展开更多
文摘This study proposes a refined methodology for controlling building heights in heritage areas.In order to protect the visual integrity of the heritage area,buildings should not obstruct the view from important site points and viewpoints to the periphery.By calculating the building height thresholds that buildings should not obscure the view from each viewpoint,the results of which are weighted and superimposed,and the values are extracted to each building unit as a refined building height control guideline.This study takes the Zhoukoudian area as a case study,applies the refined building height control criterion to the Zhoukoudian Site,and relies on this refined criterion to assess the visual integrity of the Zhoukoudian area,so as to realize the scientific planning and monitoring of the Zhoukoudian area.The refined building height control method can be applied to building height planning and visual landscape protection in large heritage areas.
基金Under the auspices of National Natural Science Foundation of China(No.41771001)Science and Technology Planning Project Funds of Guangzhou(No.201704020136)。
文摘Understanding the spatiotemporal patterns of three-dimensional urban forms,especially building height,can have important implications for improving urban air quality and mitigating the urban heat island effect by optimizing urban planning and management policies.This study investigated building height evolution and its influencing factors over approximately half a century(1960–2017)in Guangzhou,China.The results indicated that the logarithmic declines in height,quantity,and area of urban buildings followed Zapf’s law,which restricts the three-dimensional shape of the urban form.The urban building height decreased from the center to the periphery of the city and decreased with decreasing altitude and increasing distance from main roads.These characteristics constituted the three main spatial differentiation rules of building height in the central district of Guangzhou,and all exhibited a logarithmic decrease,which gradually strengthened over time.The development of a double-layered height structure of low-rise and high-rise buildings between 1990 and 2017 was a notable manifestation of the increase in vertical urban height over time.The three factors of city center,altitude,and accessibility,which represent centrality,low relief,proximity to water,and proximity to road networks,highlighted the roles of traffic accessibility and commercial attraction in building height evolution.The importance of location macroscopically depends on the combined effect of the geographical pattern,urban planning,and market forces of cities located on a plain near hill or by a river.The principle of profit orientation restricted spatiotemporal building height patterns.
文摘Building geometry data is crucial for detailed, spatially-explicit analyses of the building stock in energy systems analysis and beyond. Despite the existence of diverse datasets and methods, a standardized and validated approach for creating a nation-wide unified and complete dataset of German building heights is not yet available. This study develops and validates such a methodology, combining different data sources for building footprints and heights and filling gaps in height data using an XGBoost machine learning algorithm. The XGBoost model achieves a mean absolute error of 1.78 m at the national level and between 1.52 m and 3.47 m at the federal state level. The goal is proving the applicability of the methodology at a large scale and creating a useful dataset. The resulting dataset is thoroughly evaluated on a building-by-building level and spatially resolved statistics on the quality of the dataset are reported. This detailed validation found that the building number and footprint area of German building stock is 90.31 % and 94.84 % correct, respectively, and the building height accuracy is 0.59 m at the national level. However, errors are not homogeneous across Germany and further research is needed into the impact of including additional datasets, especially for regions and building types with lower accuracies. This study proves that the chosen methodology is useful for generating a building height dataset and the workflow, with some modifications for regional data availability, can be transferred to other countries. The generated building dataset for Germany constitutes a valuable data basis for the research community in fields such as energy research, urban planning and building decarbonization policy development.
文摘Rational urban design helps to build sustainable cities with high ventilation capacity and pollutant removal ca-pacity,but the effect of building height on ventilation and pollutant dispersion inside asymmetric canyons has not been fully studied.In this paper,we studied the effect of increasing the degree of building height asym-metry(DBHA)on canyon ventilation and pollutant diffusion in shallow and deep asymmetric street canyons by considering six different building height ratios(BHR=3/4,1/2,1/3,4/3,2/1 and 3/1).The results show that increasing the DBHA in asymmetric canyons can improve the ventilation and pollutant removal capacity.For step-up canyons,increasing the downwind building height is very useful to improve ventilation and pollutant re-moval.For shallow/deep step-up canyons with BHR=1/3,the air exchange rate(ACH)increased to 211.2%and 380.1%of the flat canyons,respectively.The spatially-average pollutant concentration in the pedestrian zones(leeward Kavg∗ang windward Kavg∗)decreases significantly with the increase of DBHA,especially for the deep step-up canyon with BHR=1/3,the leeward Kavg∗and windward Kavg∗decrease to 15.3%and 3%,respectively.Also,increasing the upwind building height can also improve the ventilation capacity in the step-down canyons.For the deep step-down canyon with BHR=3/1,the leeward Kavg∗and windward Kavg∗decreased to 40.6%and 24.1%of the deep flat canyon,respectively.Notably,the ventilation capacity is very low for step-down canyons with BHR=4/3,and for step-down canyons with BHR≥2/1,the ventilation capacity and pollutant removal capacity increase significantly with the increase of DBHA.Therefore,in urban planning,step-down canyons with BHR=4/3 should be avoided and designed to satisfy the condition of BHR≥2/1.These findings will be a valuable reference for urban designers to build sustainable cities with high ventilation capacity.
文摘As part of a broad strategy to reach net-zero greenhouse gas emissions and limit global warming,many countries are requiring all new buildings to have net-zero energy use.This requires that on-site energy use not exceed on-site generation of renewable energy(taken here to be solar energy),or equivalently,that the building Energy Use Intensity(EUI,kWh/m^(2)a)not exceed the supply of on-site solar energy(electricity and heat)per m^(2)of floor area per year.On this basis,we find that achieving net-zero energy performance in an archetype 40-story square building in 16 different cities of North America requires EUI of 17–24 kWh/m^(2)a using PV panels,and 19–28 kWh/m^(2)a using PVT collectors.Changing building orientation to a non-square floor shape can improve maximum permitted EUI by up to 50%in PV and 60%in PVT case.Conversely,the best-performing residential and commercial buildings have EUIs of 50–75 kWh/m^(2)a.Only if building heights are limited to 5–10 floors does the available solar energy,and thus the permitted EUI,reach 50–75 kWh/m^(2)a.Therefore,we recommend that policymakers not require high-rise buildings to be net-zero energy,unless they are prepared to limit building heights to 5–10 floors.
