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Analysing the effects for different scenarios on surrounding environment in a high-density city
... It is necessary to explore how the various combinations of conditions lead to the sustainable development of urban renewal. Based on prior literature and on our observations, the antecedent conditions of this research contain the preservation of history and culture, differentiation, commercial publicity, project reformation and incremental innovation (Ye, 2019;Arbab et al., 2020;Guo et al., 2020;Che et al., 2021). ...
... Projects can be reconstructed through partial demolition, functional replacement and select repairs. Project reformation may optimize regional functions, improve the living environment, and stimulate the vitality of old buildings, which make these buildings enter the public's field of vision again (Wang et al., 2017;Guo et al., 2020). For instance, after reformation, many old streets and buildings can be reused and some related industries with similar cultural background are willing to utilize them at a lower cost compared with establishing new buildings. ...
Even though urban renewal has attracted much attention in recent years, relatively few studies focus on the sustainability of urban renewal projects, which is surprising given the associated economic benefits. To fill this gap, we review 31 typical cases of urban renewal in China that have existed for over 10 years and utilize fuzzy set qualitative comparative analysis (fsQCA) to identify causal configurations that lead to a high level of stakeholder satisfaction. Our findings show that: (1) there are four antecedent configurations that lead to the sustainability of urban renewal of urban renewal (these are: ~ preservation of history and culture * differentiation * project reformation * ~ incremental innovation; ~ preservation of history and culture * differentiation * commercial publicity * incremental innovation; preservation of history and culture * commercial publicity * ~ project reformation * incremental innovation; and preservation of history and culture * differentiation * ~ commercial publicity * project reformation * incremental innovation); (2) compared with other conditions, differentiation and incremental innovation play more important roles in the sustainability of urban renewal; and (3) not only the improvement of the environment but also the operation and management of projects should be considered carefully. This paper contributes to urban renewal literature and offers practical suggestions for sustainable urban development.
... Improving the microclimate is not always a primary objective of waterfront design regulations, but such guidelines appear to have some impact on the microclimate. Given that one of the variables influencing microclimates is built-environmental conditions, such as building design, floor area ratio, and building height, waterfront design strategies are likely to create microclimate changes even though urban planners do not intend this consequence [28][29][30][31]. ...
... They revealed that increasing the height of waterfront buildings by two and four times reduced air velocity in a street canyon by 30% and 40%, respectively. Furthermore, Guo et al. [30] investigated changes in air temperatures and wind speeds in hypothetical planning scenarios based on plot ratios and building heights in the Kai Tak area of Hong Kong using ENVI-met. The findings indicated that significant variations in microclimate conditions occurred when the plot ratio and building height were at least doubled. ...
Water bodies, such as rivers, ponds, and lakes, act as natural landscape resources to improve the urban microclimate. However, the cooling effects of water bodies may be lessened as a result of poorly planned buildings along the waterfront due to the “wall effect.” This research aimed to investigate the microclimate impacts of the following three strategies typically used in waterfront development: 1) building height restriction, 2) ventilation corridors, and 3) stepped building height variation. To compare the microclimate change after applying each strategy, we calculated the air temperature, wind speed, mean radiant temperature, and thermal comfort using the numerical simulation with microclimate simulation software, ENVI-met. The results showed that each strategy led to different microclimate patterns. The restriction on building height had a negative impact on the microclimate, increasing the physiological equivalent temperature by up to 1.34 °C. In contrast, the ventilation corridor provided a moderate cooling effect during the afternoon. Lastly, the stepped building height variation strategy did not have an effect on thermal comfort. The results suggest that the microclimate-related strategies for waterfront development did not always contribute to the improvement of thermal comfort; thus, additional heat-mitigation solutions are needed.
... Since three dimensions enable representation and visualization of real-world space better than two dimensions, many urban development studies have been conducted using 3DSAT. The viability of using 3DSAT to study urban development has been touched upon by Ranzinger and Gleixner (1997), Pullar and Tidey (2001), Zhang et al. (2004), Mak et al. (2005), Thill et al. (2011), Leszek (2015, and Guo et al. (2017Guo et al. ( , 2020, all of whom achieved effective results that help with making urban planning decisions. The increased application of 3DSAT for urban development has resulted in the following proposed tools based on 3DSAT: a GIS tool for urban climate evaluation (Li et al. 2004) and for community engagement in urban planning (Foth et al. 2009); an original 3D GIS methodology developed by Wong et al. (2011) for investigating the wall effect caused by the proliferation of tall buildings along the coast of Kowloon in Hong Kong; a platform for assisting decision making in urban development projects (Isaacs et al. 2011); an integrated approach for assessing residential development (Xu and Coors 2012); and a framework for assessing the development potential of Liuzhou city in China (Xia et al. 2016). ...
... The development of the Green Deck project and its environmental influence can be addressed in terms of solar exposure, wind ventilation, air temperature, and human thermal comfort changes. Similar research was conducted by Guo et al. (2017Guo et al. ( , 2020 on PR/BH relaxation and related analyzes using the 3D spatial analysis technology in the Kai Tak Development Area (KTDA) of Hong Kong. However, since most of the KTDA was still under construction, all the 3D building models of different scenarios were generated based on the blueprints (EKEO 2012). ...
... Creating a comfortable environment covers the economic and social spheres, housing, transport and road sectors , education and healthcare. The problem of urban environment comfort (Bekiaris et al. 2017, Habib et al. 2014) becomes urgent in the conditions of the rapid growth of metropolis population (Guo et al. 2020), development of social and economic processes (Bitkina et al. 2019), digitizing ...
... Creating a comfortable environment covers the economic and social spheres, housing, transport and road sectors , education and healthcare. The problem of urban environment comfort (Bekiaris et al. 2017, Habib et al. 2014) becomes urgent in the conditions of the rapid growth of metropolis population (Guo et al. 2020), development of social and economic processes (Bitkina et al. 2019), digitizing of all areas of social development, and increasing transport activity of the population (Seliverstov et al. 2017a). This results in an impaired environmental and sanitary situation (Menges and Boltze 2020), labor market contraction, deterioration of health and life quality of citizens. ...
The paper studies the possibility of using mobile apps for quality control of the urban environment, road networks and transport servicing of the population. We analyze Russian and foreign technical solutions and specify the set of functional user features of the developed application. Based on an online survey in Google Forms, we determine the demand for the application along with the preferable set of functions. iOS is selected as an operational system to run the mobile app. To develop the app based on the iOS platform, Clean Swift architecture is chosen. Marker criteria are developed and selected to evaluate the quality of the urban environment and road networks. The Scrum model is chosen as a life cycle model. The app is developed and tested in the X-Code environment with Swift. The data analysis module is written in Python_3. The app is tested in the TestFlight environment. Guidelines for further development of the developed tools within intelligent transport systems and Smart City are identified.
... Analyzing the effects of different scenarios on the surrounding environment in a high-density city [59] Soil Impacts of urban expansion on relatively smaller surrounding cities during heat waves [60] Soil ...
Megacities boost peri-urban socioeconomic development but fulfill their high natural resource demands by overexploitation, yielding irreversible environmental damage in surroundings that turn into sacrifice zones. This study reports the effects on the Cuautitlán-Pachuca Valley, the Mexico City main expansion zone at the northeast of the metropolitan area on the Central Mexico plateau, the trend scenarios from 2020 to 2050, and the actions to mitigate the growing water demand that will worsen its aquifer overexploitation. We designed a conceptual archetype to apply the Water Evaluation and Planning System (W.E.A.P.) mathematical model calibrated with 2013–2014 data to calculate groundwater volume demand in future scenarios. The demand output for the international airport and agriculture was less than 5%. The local climate change effect up to 2050 will slightly reduce the infiltration. The most crucial water demand increase (195% in 2050) is due to the population and industrial growth of the Mexico City northern municipalities (89% of the total groundwater extraction volume), and the aquifer will have a notable −2192.3 hm³ accumulated deficit in 2050, while urban sprawl will decrease water infiltration by 2.3%. Mitigation scenarios such as rainwater harvesting may reduce the urban water supply only by 9%, and a leak cutback will do so by 24%, which is still insufficient to achieve sustainable water management in the future. These outcomes emphasize the need to consider other actions, such as importing water from near aquifers and treating wastewater reuse to meet the future water demand.
... Moreover, their development shapes urban landscapes, accentuating intra-urban heterogeneity (Batty & Marshall, 2016;Liu & Wang, 2016) and thus generating complex UHI patterns that challenge conventional urban-rural UHI intensity research (Liu & Wang, 2016;Stewart & Oke, 2012). Consequently, new research perspectives aligned with the dynamic traits of urbanization are essential to enrich the comprehension of UHI and its mitigation strategies (Guo et al., 2020;Kwan, 2012;Parsaee et al., 2019;Peng et al., 2022). Notably, the foundational aspect of new town developmentland use arrangementcharacterized by high adaptability and capacity, warrants exploration of how land use function (LUF) influences UHI effects . ...
New town developments aim to improve spatial layout and quality of human habitats in metropolitan areas. However, due to high-density compact development and inadequate long-term land use planning, new towns are vulnerable to urban heat island effects. This study addresses this concern by analyzing five new towns in Shanghai, using spatial pattern analysis to examine morphological conditions of urban heat island and Point-of-Interest datasets to derive functional characteristics. Geodetector is then used to detect the influence of land use function density on urban heat island. Findings reveal that new towns are more prone to urban heat island effects, with core-type dominant in suburban new towns, loop-type in sprawling new towns, and bridge-type in regional new towns. The study proposed targeted strategies based on morphological characteristics, including greenbelt transformations for core-types and using greenbelts to interrupt bridge-type connections. Findings also reveal strong thermal influence from public services, interactive effects of parks with other functions, and lower thermal influence from mixed education and commercial developments. Similar thermal mechanisms stem from spatial proximity and similar development patterns in new towns. Incorporating these target strategies into planning practice enables urban planners and policymakers to develop effective interventions against urban heat island in new towns.
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... Because of the significant negative influence of PM 2.5 on climate change (Bellouin et al., 2020;Nazarenko et al., 2017) and public health (Geng et al., 2021;Xie et al., 2016), China has recently employed strict emission control measures . Studies have been carried out to address the challenges of environmental and climatic degradation by means of urban layout optimization (Guo et al., 2020), emission source statistics , and future emission scenario predictions (Ali et al., 2019). PM 2.5 not only originates from local emissions, but also from regional transport . ...
Source-tagged source apportionment (SA) has advantages for quantifying the contribution of various source regions and categories to PM2.5; however, it is highly affected by uncertainty in the emission inventory. In this study, we used a Regional multi-Air Pollutant Assimilation System (RAPAS) to optimize daily SO2, NOx and primary PM2.5 (PPM2.5) emissions in the Yangtze River Delta (YRD) in December 2016 by assimilating hourly in-situ measurements. The CMAQ-ISAM model was implemented with prior and posterior emissions respectively to investigate the impacts of optimizing emissions on PM2.5 SA in the YRD megalopolis (YRDM) and three megacities of Shanghai, Nanjing, and Hangzhou in the YRDM. The results showed that RAPAS significantly improved the simulations and reduced the emission uncertainties of the different pollutants. Compared with prior emissions, the posterior emissions in the YRD decreased by 13% and 11% for SO2 and NOx respectively, and increased by 24% for PPM2.5. Compared with SA using prior emissions, the contributions from Hangzhou, northern Zhejiang, and areas outside of the YRD to the YRDM increased. The local contributions from the YRDM, Nanjing and Shanghai decreased by 1.8%, 9.7%, and 2.3%, respectively, whereas that of Hangzhou increased by 5.6%. The changes in the daily local contributions caused by optimizing emissions ranged from −18.0% to 23.6%. Generally, under stable weather conditions, the local contribution changed the most, whereas under unstable weather conditions, the contribution from upwind areas changed significantly. Overall, with optimized emissions, we found in Nanjing, Shanghai, and Hangzhou, local emissions contributed 18.2%, 39.6% and 36.8% of their PM2.5 concentrations, respectively; long-range transport from outside the YRDM contributed 59.2%, 48.1%, and 48.2%, respectively. This study emphasizes the importance of improving emission estimations for source-tagged SA and provides more reliable SA results for the main cities in the YRD, which will contribute to pollution control in these regions.
... Conversely, the different heights of the buildings' canopy morphology change the radiation transmission process between the sun and the surface, which includes the absorption of solar radiation and the emission of long-wave radiation from the surface [14,15]. Therefore, scholars focused on the study of the influence of three-dimensional building morphology on the urban thermal environment [16][17][18]. ...
Urban building morphology has a significant impact on the urban thermal environment (UTE). The sky view factor (SVF) is an important structure index of buildings and combines height and density attributes. These factors have impact on the land surface temperature (LST). Thus, it is crucial to analyze the relationship between SVF and LST in different spatial-temporal scales. Therefore, we tried to use a building vector database to calculate the SVF, and we used remote sensing thermal infrared band to retrieve LST. Then, we analyzed the influence between SVF and LST in different spatial and temporal scales, and we analyzed the seasonal variation, day–night variation, and the impact of building height and density of the SVF–LST relationship. We selected the core built-up area of Beijing as the study area and analyzed the SVF–LST relationship in four periods in 2018. The temporal experimental results indicated that LST is higher in the obscured areas than in the open areas at nighttime. In winter, the maximum mean LST is in the open areas. The spatial experimental results indicate that the SVF and LST relationship is different in the low SVF region, with 30 m and 90 m pixel scale in the daytime. This may be the shadow cooling effect around the buildings. In addition, we discussed the effects of building height and shading on the SVF–LST relationship, and the experimental results show that the average shading ratio is the largest at 0.38 in the mid-rise building area in winter.
... These countries are in the high-speed developmental phase of an agricultural economy and the industrial economy, i.e., they try to pursue both developments simultaneously. Some cities use urban growth scenarios to simulate urban areas at different development speeds to evaluate the current urban planning to meet future population demand and economic development (Alsharif and Pradhan, 2014;Estoque and Murayama, 2012;Guo et al., 2020;Syphard et al., 2005). Therefore, simulating urban growth scenarios can help monitor progress to meet urgent development targets. ...
In the past two decades, urbanization has been accelerating worldwide. The rapid increase in population has negatively impacted the urban environment and the quality of life. Today, as a result of rapid economic growth and urban development, many cities suffer from numerous problems such as traffic congestion, noise, air and water pollution, etc. With such conditions worsening, various scenario simulation analyses have been conducted to predict future urbanization to aid the management of sustainable urban development. This paper examines research trends and the usefulness of urban scenario modeling by conducting an extensive survey of articles on urban land-use scenario simulations. We discuss the advantages and limitations of urban scenario analyses via a systematic and quantitative review. The focus is on global planning designs, urban planners, and politicians who should draw up suitable frameworks to implement sustainable urban development policies. We conclude that sophisticated scenario modeling could help achieve Sustainable Development Goals (SDGs).
The purpose of this study is to use thermal environment analysis to investigate architectural design strategies for vacant land in high-density cities. Researchers used Rhino to construct a 3D model of the Macau BT8 and BT9 plots and imported the collected data, including terrain, meteorology, and surrounding buildings, into the model to accurately replicate the actual spatial environment. Moreover, we used Ladybug analysis to determine the sunshine distribution of the plot at a specific time. Finally, a design solution with a visual rendering effect was proposed by combining the upper-level planning constraints with the thermal environment simulation analysis results.
Increasing urbanisation has inevitably led to the continuous construction of buildings. Urban expansion and densification processes reshape cities and, in particular, the third dimension (3D), thus calling for a technical shift from 2D to 3D for property valuation. However, most property valuation studies employ 2D geoinformation in hedonic price models, while the benefits of 3D modelling potentially brought for property valuation and the general context of digital twin (DT) creation are not sufficiently explored. Therefore, this review aims to identify appropriate urban 3D modelling method(s) for city DT, which can be used for 3D property valuation (3DPV) in the future (both short-term and long-term). We focused on 3D modelling studies investigating buildings and urban elements directly linked with residential properties. In total, 180 peer-reviewed journal papers were selected between 2016 and 2020 with a narrative review approach. Analytical criteria for 3D modelling methods were explicitly defined and covered four aspects: metadata, technical characteristics, users’ requirements, and ethical considerations. From this, we derived short-term and long-term prospects for 3DPV. The results provide references for integrating 3D modelling and DT in property valuation and call for interdisciplinary collaboration including researchers and stakeholders in the real estate sector, such as real estate companies, house buyers and local governments.
Building height, building density, and floor area ratio are the three key parameters in urban planning. However, little is known about their impact on indoor thermal environments as compared with outdoor thermal environments. The study aimed to investigate their impact on indoor air temperatures in Singapore. Singapore's residential buildings were reviewed from the perspective of the three parameters, and the Envi-met model was employed for simulation after its accuracy was confirmed by field experiments. Indoor air temperatures under 18 scenarios were simulated and analyzed. The analytical results revealed that among the three parameters, the building density was the most influential. An increase in building density reduced the indoor temperature. In Singapore, the building density increases from 0.0625 to 0.766, which reduced the mean indoor temperature by 4.7 °C. The indoor temperature decreased slightly with an increase in building height. An increase in building height from 12 to 72 m produced an indoor temperature decrease of approximately 1.7 °C. The influence of floor area ratio on indoor air temperature was the most complex. For a fixed floor area ratio of 2, the indoor temperature first increased and then decreased with an increase in building density, which resulted in an indoor temperature difference of 2.1 °C when the building density increased from 0.141 to 0.766.
Работа посвящена исследованию возможности использования мобильных приложений для контроля качества городских улично-дорожных сетей и транспортного обслуживания населения. Производится анализ предметной области и дается обзор зарубежных и российских технических решений. На основе проведенного интернет опроса в среде Google Forms определяется степень востребованности приложения пользователями и определяется предпочтительный набор функций. Для разработки мобильного приложения на платформе iOS используется архитектура Clean Swift. В качестве базы данных выбирается облачный сервис Firebase Realtime DataBase. Разрабатывается графическая библиотека маркеров-критериев для оценки качества городских улично-дорожных сетей. В качестве модели жизненного цикла используется модель Scrum. Осуществляется разработка и тестирование приложения в среде Xсode на Swift 4.0. Приложение позволяет пользователю наносить на карту маркеры, отражающие соответствующие события, связанные с качеством улично-дорожной сети с учетом различных способов передвижения, городской среды, настроения и состояния здоровья окружающих людей и задавать бальную оценку событиям. Модуль для анализа данных написан на языках Python 3.6 и JavaScript с использованием библиотек flask, leaflet.js, pandas, geopy, folium. Модуль для анализа данных осуществляет обработку данных с Firebase Realtime DataBase с формированием детализированного отчета по всем событиям за анализируемый период. Также в процессе анализа данных осуществляется расчет критерия качества рассматриваемой области, адресная идентификация отмеченного события путем перевода gps-координат этого события в конкретный адрес, маркерной визуализацией всех событий за анализируемый период на карте с помощью библиотеки leaflet.js, а также оценкой качества уличнодорожной сети с использованием тепловых карт. Производится тестирование приложения в среде дистрибуции TestFlight и апробируется работоспособность системы на примере оценки качества городской улично-дорожной сети Санкт-Петербурга. Обозначаются ориентиры дальнейшего развития разработанного инструментария в составе интеллектуальных транспортных систем и Smart City.
In the first half of 2020, millions of people were subjected to drastic restrictions aimed at limiting the spread of the Covid-19 disease. Austria, France and Poland have implemented a lockdown to varying degrees and for varying lengths of time. This is an unprecedented situation in Europe: until now, even in times of war, curfew measures have never been applied 24 h a day. The research presented in this article was carried out in real time, in April and May 2020, with the help of urban planning students from three countries. Its objective is to observe the interaction between these measures and the urban space in two dimensions. On the one hand, we analyse the impact of these measures on the urban space and on the spatial practices of the inhabitants. On the other hand, we examine the conditions which different types of urban and rural space have provided for the inhabitants experiencing confinement. This empirical study leads to a discussion and recommendation for the town planners of the future.
In the first half of 2020, millions of people were subjected to drastic restrictions aimed at limiting the spread of the Covid-19 disease. Austria, France and Poland have implemented a lockdown to varying degrees and for varying lengths of time. This is an unprecedented situation in Europe: until now, even in times of war, curfew measures have never been applied 24 h a day. The research presented in this article was carried out in real time, in April and May 2020, with the help of urban planning students from three countries. Its objective is to observe the interaction between these measures and the urban space in two dimensions. On the one hand, we analyse the impact of these measures on the urban space and on the spatial practices of the inhabitants. On the other hand, we examine the conditions which different types of urban and rural space have provided for the inhabitants experiencing confinement. This empirical study leads to a discussion and recommendation for the town planners of the future.
Under low latitude conditions, minimization of solar radiation within the urban environment may often be a desirable criterion in urban design. The dominance of the direct component of the global solar irradiance under clear high sun conditions requires that the street solar access must be small. It is well known that the size and proportion of open spaces has a great influence on the urban microclimate This paper is directed towards finding the interaction between urban canyon geometry and incident solar radiation. The effect of building height and street width on the shading of the street surfaces and ground for different orientations have been examined and evaluated. It is aimed to explore the extent to which these parameters affect the temperature in the street. This work is based on air and surface temperature measurements taken in different urban street canyons in EL-Oued City (hot and arid climate), Algeria. In general, the results show that there are less air temperature variations compared to the surface temperature which really depends on the street geometry and sky view factor. In other words, there is a big correlation between the street geometry, sky view factor and surface temperatures.
The geographical visualization of urban and regional landscapes is a powerful technique for engaging actors involved in decision-making processes. Tools developed can empower professional and citizen alike to make better-informed decisions. The paper reports on collaborative research being undertaken to develop and apply a range of 3D geographical visualization products to enhance both planning and scientific com-munication processes. In this paper we discuss some developments and applications of 3D geographical visualization tools and work being undertaken to evaluate the effectiveness of such tools for solving spatial planning problems. The paper concludes by discussing the lessons learnt in undertaking a cross-disciplinary approach to developing and applying landscape visualization tools and offers some future research directions with respect to technical specifications and the usefulness of geographical visualization as a participatory planning support tool.
The city’s outdoor wind-heat environment which plays an important role of improving citizen's livelihood has become a focus of research. For the outdoor public space similar to the pedestrian street, pedestrian-height wind and thermal comfort directly influence the value. This paper takes Jiefangbei commercial pedestrian street as an example. Based on the regional climate characteristics in Chongqing, simulation has been carried out by ENVI-met software. Then this paper makes comprehensive evaluation on pedestrian-height wind environment and thermal comfort, and proposes optimization measures according to the existing problems so as to create an outdoor space environment suitable for improving people's way of life in city.
High density development in cities is a planning strategy responding to fast population growth and limited land resources. However, the agglomeration of building mass increases the solar radiation heat gain, especially in the tropics. In order to understand how various high density residential urban forms perform in terms of overall surface solar insolation, we propose a performance indicator to quantify the solar radiation performance and a methodology to evaluate and compare the theoretical insolation performance across various urban forms. The impacts of selected morphological and geometric parameters on insolation performance are analysed to identify key design attributes contributing to insolation minimization.
The effect of urban development on local thermal climate is widely documented in scientific literature. Observations of urban–rural air temperature differences—or urban heat islands (UHIs)—have been reported for cities and regions worldwide, often with local field sites that are extremely diverse in their physical and climatological characteristics. These sites are usually described only as “urban” or “rural,” leaving much uncertainty about the actual exposure and land cover of the sites. To address the inadequacies of urban–rural description, the “local climate zone” (LCZ) classification system has been developed. The LCZ system comprises 17 zone types at the local scale (102 to 104 m). Each type is unique in its combination of surface structure, cover, and human activity. Classification of sites into appropriate LCZs requires basic metadata and surface characterization. The zone definitions provide a standard framework for reporting and comparing field sites and their temperature observations. The LCZ system is designed primarily for urban heat island researchers, but it has derivative uses for city planners, landscape ecologists, and global climate change investigators.
This study proposes a method to create an urban planning support model, applying the Environment and energy Geographical Information System Database (E-GIS DB) through the urban life cycle to reduce energy use for environmentally friendly urban planning. The results deduced from this study are organized as follows.The proposed E-GIS construction model is composed of (a) an urban GIS integration model, (b) an E-GIS DB model, and (c) a visualization model. The urban GIS integration model has the ability to integrate urban GIS constructs as well as to connect and visualize urban planning and the environment and energy DB in 3D space. The E-GIS DB model includes a function to visualize the 2D and 3D information, which is used in the environment and energy planning of a city.To validate the proposed E-GIS construction model, a Korean city undergoing the urban planning process is selected as a case study. An E-GIS DB section with an 8 km × 12 km area for the research subject area was constructed in 2D and 3D GIS, and the urban space, climate elements, and energy distribution characteristics are compared.
A skyline is a unique fingerprint of a city. The mentalities, diversity, and cultures in a city can often be perceived from its skyline. Istanbul's iconic skyline forms an essential part of the character and appearance of this mega city, so much so that Istanbul's historical silhouette is instantly recognizable; it is a unique asset that is important to protect. Impressive minarets and domes dominate the skyline of Istanbul. On the other hand, Istanbul's skyline has changed dramatically over the last decade since land has become increasingly an opportunity for investment and building of taller structures has become one way to multiply this profit. For those who focus on the esthetics of cities, the analysis of the skyline is not a recent phenomenon. However, skyline extraction and analysis has not usually been available in current GIS functionality. This article investigates the esthetics the urban skyline and its transformation due to high-rise buildings. It does this by tailoring a geomodel within a GIS environment. It is believed that the geomodel developed in this study will form a solid foundation which can be applied to many of the urban skylines and urban areas in Turkey and other cities of the world.
Hong Kong is well known for its high-density form of development. Such form of development is shaped either by new development or urban renewal, which is a major tactic nowadays adopted by the Hong Kong Government to improve the living condition of the public and the quality of the built environment. Urban renewal is the main focus of this study, which aims to highlight the deficiencies of current (re)development practices conducted in Hong Kong and explain how the major urban design considerations shortlisted from the literature can sustain local community in various aspects. Through a questionnaire survey and subsequent data analyses, the opinions of local design professionals and citizens were sought and evaluated, and critical design factors for enhancing sustainability of urban renewal projects were identified. It is expected that the findings of this paper can provide an insight to local developers, urban designers, and government officials on how to design sustainable urban renewal projects in the future.
This study focuses on the optimum cooling effect of trees with ground materials modification in mitigating the urban heat island (UHI) and the benefits towards building energy performance in tropical climate. The modification focused on both physical properties – i.e. tree canopy density and quantity; and the albedo values of ground materials. Two phases of methodology were developed and applied using field measurement and computer simulation. This study measured the average monthly UHI intensity found to be +2.6 °C. In mitigating its impact, higher levels of tree canopy density (LAI 9.7) coupled with “cool” materials (albedo of 0.8) produced the largest urban air temperature reduction. Simulations predicted an average air temperature reduction of 2.7 °C when compared with the current condition. Further, both modifications were found to produce a potential building cooling load reduction of up to 29%. In fact, the optimum improvement of both outdoor and indoor environment was influenced by three major physical factors, namely, larger tree quantity, higher canopy density and cool materials. Thus, it is suggested that appropriate guidelines, influencing implementation of these improvements could be implemented in order to mitigate the UHI effect in tropical climate.
Hong Kong is a high-density sub-tropical city with 7 million people living in an urban area of just over 260 km2. Tall and closely packed buildings are the common urban morphology. How the urban geometry influences the microclimate in summer daytime is a primary planning concern. The sky view factor (SVF) has been commonly used to indicate the impact of urban geometry on air temperature differences in cities. However, only limited discussions in this aspect have been addressed for daytime course in high-rise and high-density urban environment such as Hong Kong. This paper firstly provides a comprehensive review of SVF analysis in urban climatology studies and then presents a simulation approach to investigate the role of SVF in determining summer daytime intra-urban air temperature differences in urban Hong Kong. An ArcGIS-embedded computer program is developed for calculating continuous SVF values for an entire urban environment and an SVF map is generated. The result is evaluated against meteorological data observed in field measurements. The regression analysis shows that the spatial average of SVF values has a close negative relationship with daytime intra-urban temperature differences. The study indicates that SVF is a significant factor for understanding the microthermal climate in Hong Kong's street canyons. The paper further raises discussions on the application of SVF analysis to urban planning. The study demonstrates that the SVF analysis is a useful and effective tool for planners and urban climatologists conducting studies on high-rise and high-density sub-tropical cities. The understanding can provide support for the development of planning standards and good practice. Copyright © 2010 Royal Meteorological Society
Problem statement: The significance of urban design and planning in the tropics lies mostly on its climatic and regional concerns. Among many design parameters, building height is an important parameter which affects thermal climate in the city considerably. This study investigated the effect of building height on outdoor thermal comfort during the daytime in summer in Dhaka, Bangladesh which is a high density city located in tropical climate zone. This study emphasized on pedestrian comfort condition in a planned residential area in the city. Approach: Thermal comfort was assessed in terms of Temperature-Humidity-Index (THI) which uses air Temperature (T<SUB>a</SUB>) and Relative Humidity (RH). Measurements were carried out in a typical summer day. In addition, to simulate the urban thermal climate, a 3D numerical simulation tool ENVI-met was used. Results: Simulated results showed close agreement with the measured data in case of existing canyon and thus the validity of the present numerical simulation was confirmed. Results showed that in case of existing canyon with average building height of 4-5 storied, THI lies in the discomfort level. A canyon was proposed by increasing the building height to 8-10 storied in the existing canyon. In case of proposed canyon, it was found that increased building height provides comparatively comfortable condition than the existing case during day time. Moreover, mean radiant temperature (T<SUB>mrt</SUB>), surface Temperature (T<SUB>s</SUB>) and wind speed were included in the present study to identify the effects of building height on these factors. Conclusion: The present study had an implication on the urban design process to achieve a more comfortable urban environment by mitigating heat stress in summer.
Sustainable urban planning decisions must not only consider the physical structure of the urban development but the economic, social and environmental factors. Due to the prolonged times scales of major urban development projects the current and future impacts of any decision made must be fully understood. Many key project decisions are made early in the decision making process with decision makers later seeking agreement for proposals once the key decisions have already been made, leaving many stakeholders, especially the general public, feeling marginalised by the process. Many decision support tools have been developed to aid in the decision making process, however many of these are expert orientated, fail to fully address spatial and temporal issues and do not reflect the interconnectivity of the separate domains and their indicators. This paper outlines a platform that combines computer game techniques, modelling of economic, social and environmental indicators to provide an interface that presents a 3D interactive virtual city with sustainability information overlain. Creating a virtual 3D urban area using the latest video game techniques ensures: real-time rendering of the 3D graphics; exploitation of novel techniques of how complex multivariate data is presented to the user; immersion in the 3D urban development, via first person navigation, exploration and manipulation of the environment with consequences updated in real-time. The use of visualisation techniques begins to remove sustainability assessment’s reliance on the existing expert systems which are largely inaccessible to many of the stakeholder groups, especially the general public.
The majority of the world's citizens now live in cities. Although urban planning can thus be thought of as a field with significant ramifications on the human condition, many practitioners feel that it has reached the crossroads in thought leadership between traditional practice and a new, more participatory and open approach. Conventional ways to engage people in participatory planning exercises are limited in reach and scope. At the same time, socio-cultural trends and technology innovation offer opportunities to re-think the status quo in urban planning. NeoGeography introduces tools and services that allow non-geographers to use advanced geographical information systems. Similarly, is there a potential for the emergence of a neo-planning paradigm in which urban planning is carried out through active civic engagement aided by Web 2.0 and new media technologies thus redefining the role of practicing planners? This paper traces a number of evolving links between urban planning, NeoGeography and information and communication technology. Two significant trends - participation and visualisation - with direct implications for urban planning are discussed. Combining advanced participation and visualisation features, the popular virtual reality environment Second Life is then introduced as a test bed to explore a planning workshop and an integrated software event framework to assist narrative generation. We discuss an approach to harness and analyse narratives using virtual reality logging to make transparent how users understand and interpret proposed urban designs.
The fields of spatial planning, geographical information systems (GIS), and information and communication technology (ICT) are all developing at their own pace and in different directions, thereby obstructing the widespread acceptance of GIS as an integral part of planning practice. In this paper I take a closer look at their divergence and outline the role that a planning support system (PSS) can play in bridging this growing gap. I consider the benefits of participatory planning and show how my prototype of a PSS can contribute to its success. To that end, the functionality of this PSS is described in the context of the initial experience with its application in a diversity of planning circumstances. Some conclusions are then drawn on how a PSS can overcome some of the barriers to GIS support within planning practice.
Hong Kong is an international metropolis with a highly dense population. As a result, it faces enormous challenges in terms of land supply. As part of the Hong Kong Government's initiative to increase land supply, the Civil Engineering and Development Department (CEDD) proposed minor relaxation of the maximum plot ratio/building height restrictions for 21 target sites in Kai Tak Development Area (KTDA). Although CEDD has explored the feasibility of increasing development intensity by assessing environmental impacts, infrastructure capacity and public consultation, these reviews and assessments were conducted based on the 2D GIS. Since the spatial distribution of land unit in the real world is three-dimensional, 3D GIS can help us look into the world in true perspective and make informed decisions. This study aims to investigate the viability of minor relaxation of maximum plot ratio/building height restrictions of 21 sites in KTDA through 3D modeling and 3D spatial analyses, including skyline, visual impact, shadow and solar exposure. Regarding to the 21 target sites, four scenarios with different plot ratios and building heights were built and compared. The results indicate that minor relaxation of maximum plot ratio and building height leads to (i) minor effect on skyline (ii) minor effect on visual impact and (iii) slight changes in shadow and solar exposure both in winter and summer. Therefore, in light of the findings from this study, scenario 4 is the recommended reasonable scale to relax the maximum plot ratio/building height restriction for the target sites in KTDA. Besides, this study can also be applied in the urban renewal studies and other new development areas in Hong Kong, or even in other densely populated cities.
Observing the rapid urban expansions and numerous infrastructure developments in the East-Asian context, many cities are suffering the urban heat island (UHI) effect and its associated environmental and social challenges. Moreover, the lack of sufficient attention to the application of effective heat mitigation strategies in current urban development in these cities can drastically intensify the eventual impacts of UHI. Therefore, many governmental sectors and policy makers have been implementing operative solutions for cooling cities. Nevertheless, this study argues that in Kuala Lumpur, despite the growing attention to this matter, there is still a need for more rigorous consideration by the architecture, engineering and construction (AEC) professionals as well as more scholarly studies to reflect sustainable solutions to the UHI effect. As a result, today, some of the dense urban areas in Kuala Lumpur are characterized with the use of thermally massive building materials, urban surfaces with low albedo, complex urban morphology, waste heat, and low density of vegetation. On the other hand, recent studies demonstrate that there has been a rapidly increasing interest in studies related to UHI in other East Asian regions such as Singapore and Hong Kong. Hence, this study develops a comparative analysis to provide a state-of-the-art review of the recent attempts towards mitigating the UHI effect in Kuala Lumpur, Singapore, and Hong Kong. Among several available UHI mitigation strategies, this study is limited to the analysis of the environmental impacts of urban vegetation (green roofs, green facades, vertical greeneries and green pavements). Findings reveal that in general, urban greening can significantly mitigate the UHI intensity, both directly and indirectly, resulting in the decrease of global air temperature and mean radiant temperature up to 4 ˚C and 4.5 ˚C respectively. Overall, the study develops new practical guidelines, discusses the public benefits and elaborates on the future directions of UHI studies.
Hong Kong is a metropolis with a dense population. The need to cope with rapid population growth under the constraint of limited amounts of developable lands has resulted in a concentrated development of high-rises. Enterprising developers have clearly exploited such behaviors in the urban development of Hong Kong. Buildings have been constructed to maximum heights whenever a height restriction was not specified in the authorization to build, or stretched to their limits sideways if given a height restriction. Both of these situations have given rise to either repetitive and monotonous roofscapes or walls of regimental building flanking the harbor front. The objective of this research is to evaluate and redesign the city skyline of Hong Kong based on Urban Design Guidelines established by the Planning Department. The study makes use of the Geographic Information System (GIS) technology and its 3-dimensional (3D) modeling functions to construct, assess, and analyze the city skyline.
A three dimensional computational fluid dynamics (CFD) model based on the Reynolds-averaged Navier-Stokes equations with the standard k-ɛ turbulence scheme is applied to simulate the influence of thermal effects on air flow pattern, pressure distribution and air exchange in a regular street canyon with different thermal conditions and different background wind speeds. The results show that the thermal conditions can greatly affect the flow patterns inside the street canyon, and an impact factor w is defined to discuss the influence of thermal conditions on the static pressure distribution around the buildings. The value of w decreases with the increase of the wind speed for both upwind and downwind buildings. When the wind speed reaches a critical value (i.e., Vc), the influence of thermal effects on the pressure distributions near the buildings can be ignored. The air exchange rate in the canyon remains unchanged when the wind speed is above Vc.
This paper is about the research into the effect of building envelopes on energy consumption and thermal performance of high-rise buildings in the Malaysian Tropical climate. A suitable indoor thermal condition in buildings is important because of the building occupants comfort. In addition, it is indicating building energy consumption, staff productivity, less absenteeism, health and well-being effects. Energy consumption can be significantly reduced by adopting energy efficiency strategies in such buildings. Due to environmental concerns and expensive energy costs in recent years, energy efficiency in buildings has garnered renewed interests. A research recently conducted in Malaysia specifies that residential buildings do about 19% of the overall energy consumed in Malaysian sectors. One of the most potential strategies applied on building envelope in hot-humid tropical regions is the passive design method and is done to the building envelope in hot-humid tropical regions. This paper reviews the results of the other studies that establish to the selecting of proper parameters of building envelope to the high-rise residential. The building design criteria has been scrutinized through a set of defined parameters such as climatic conditions, form, width, length and height, external walls, roofs, glazing area, natural ventilation and occupants thermal comfort, as well as external shading devices on energy consumption of high-rise buildings in Malaysia. The thermal comfort zone was investigated by researchers for Malaysian residential buildings, discovering that the comfort ranged between 25 °C and 31 °C. Recommendations are given based on the significant findings as resources to help designers in laying out the design plan for high-rise buildings in hot and humid climate.
The urban heat island (UHI) phenomenon may produce several cascade effects on citizens' health, energy consumption and air quality. Numerical modelling is recognised to be a powerful tool for the analysis of the UHI, although the question of which model to use (as implied in the 'fit-for-purpose' approach) much depends on the application and on the result of satisfactory validation against field measurements. In this paper, two different modelling approaches are applied, namely the integral-semi-Gaussian model ADMS-TH and the CFD-based model ENVI-met, to assess the UHI phenomenon in a city of south Italy (Lecce). Modelling results are validated against field measurements collected during summer 2012. The results suggest that the integral model has the ability of capturing the UHI cycle at city scale, while CFD modelling did not provide any substantial improvements in terms of local geometric effects on temperature distribution.
Rapid urbanization and industrialization in China have seriously threatened the ecosystem and urban sustainability. This paper estimated the dynamic variations of ecosystem service value (ESV) in response to changes of land use/land cover (LULC) under rapid urbanization, and it analyzed their impacts on sustainability of urban system. Tianjin, the largest coastal city in China, was selected as the study area. The total ESV of Tianjin was approximately 8791.86 million Yuan in 2003, 7948.04 million Yuan in 2007, and 8378.53 million Yuan in 2011. By taking the total dynamic ESV as one of the key factors, we calculated the indexes of urban sustainability from 2003 to 2011. It was found that the dynamic variations of ESV in response to LULC changes had significant impacts on the sustainability of urban system. Therefore, in order to increase the capacity for urban sustainable development, there is an urgent need to lighten the heavy burden on the ecosystem through rational land use management during rapid urbanization.
There are few studies on the microclimate and human comfort of urban areas in hot dry climates. This study investigates the influence of urban geometry on outdoor thermal comfort by comparing an extremely deep and a shallow street canyon in Fez, Morocco. Continuous measurements during the hot summer and cool winter seasons show that, by day, the deep canyon was considerably cooler than the shallow one. In summer, the maximum difference was on average 6K and as great as 10K during the hottest days. Assessment of thermal comfort using the PET index suggests that, in summer, the deep canyon is fairly comfortable whereas the shallow is extremely uncomfortable. However, during winter, the shallow canyon is the more comfortable as solar access is possible. The results indicate that, in hot dry climates a compact urban design with very deep canyons is preferable. However, if there is a cold season as in Fez, the urban design should include some wider streets or open spaces or both to provide solar access.
In this study, the interaction between a tridimensional flow field and an urban street canyon, has been analyzed. Considering different ambient wind velocity intensities and directions, several numerical simulations have been performed. The aim of this study is to investigate the effect of solar radiation, within a street canyon, for various characteristics of the ambient flow field. In the first part, the buoyancy effects have been excluded and the impact of tridimensional effects on the flow field has been evaluated. In the second part, the natural convection effects on the flow structures and the heat processes have been analyzed. Through the evaluation of the Richardson number an analysis of the convective heat transfer coefficient has been performed. The results show the importance of considering a tridimensional model and the impact of the longitudinal velocity component on the heat transfer processes along the street canyon.
We develop a large-eddy simulation (LES) model based on a meteorological numerical model for a real scale street-canyon flow with rough building facets heated by a given temperature. The model is applied to a canyon with the aspect ratio of unity for two idealized heating scenarios: (1) the roof and the entire upstream wall are heated, named as ‘assisting cases’, and (2) the roof and the entire downstream wall are heated, named as ‘opposing cases’. These facets were heated up to 15 K above the air temperature. A wall function for temperature is proposed for a rough facet with an assumption that the thermal roughness length, z
0T, is much smaller than the aerodynamic roughness length, z
0. It is demonstrated that the sensible heat flux and canyon-air temperature are significantly influenced by the near-facet process that is parametrized by z
0T as the primary factor; other processes such as in-canyon mixing and roof-level exchange are secondary. This new finding strongly suggests that it is vital to choose an appropriate value of z
0T in a numerical simulation of street-canyon flows with the facet-air exchange processes of heat or any scalar. The finding also raises an awareness of the demand for carefully designed laboratory or field experiments of quantifying z
0T values for various urban surfaces. For the opposing cases, an unsteady penetrating narrow updraft zone appears occasionally along the heated wall and this feature is consistent field observations. The unique result indicates the superior capability of LES. The results of this study can be used to guide the parametrization of turbulent processes inside the urban canopy layer.
Greening is a useful mitigation strategy for planners mainly from a visual perspective. For high-density urban living environment such as Hong Kong, urban greening helps cooling the air and providing shade; it also helps lowering building energy consumption by providing a better outdoor boundary condition. Many researchers have also suggested that greening may be employed as a strategy for combating the ill effects of urban Heat Island (UHI). Working towards a set of better greening guidelines for urban planners, the current paper first provides a comprehensive review of planning with urban greening. It then describes parametric studies that have been conducted to investigate the preferred location, amount, and types of vegetation for urban planning. The parametric studies employed the numerical model ENVI-met, verified using field measurements, to simulate 33 cases with different combinations of factors. For benefiting urban activities, ambient air temperatures at the pedestrian level are compared among different greening strategies and building heights. For a city such as Hong Kong, which has a high building-height-to-street-width (H/W) ratio, the present study reveals that roof greening is ineffective for human thermal comfort near the ground. Trees are also suggested to be more effective than grass surfaces in cooling pedestrian areas. The amount of tree planting needed to lower pedestrians level air temperature by around 1 °C is approximately 33% of the urban area. The present study allows urban planners to identify more precisely the greening principles, amount and policies necessary for better urban living environment in high-density cities.
Assessment of urban carrying capacities with respect to their basic infrastructure provisions like water supply and sanitation helps to determine the relative potentials of individual urban centres across regions for sustainable growth and also provides a framework for rational sectoral and spatial allocations of resources for infrastructure development. While carrying capacities should be assessed against acceptable norms and standards for provision of the basic services, there is ample scope for further development of minimum standards for urban water supply and sanitation in India. There has been a multiplicity of recommendations of standards with wide disparity across them and the rationale behind these recommendations are not explicit. The paper develops an array of indicator measures through which the natural and man-made resources and assimilative capacities of urban areas with respect to water supply, sewerage, drainage and solid waste disposal can be assessed in quantitative and qualitative terms. Another set of indicators have been developed to assess the financial and managerial capacities of various local institutions in the provision of these utilities. A framework for the use of these urban carrying capacity measures in spatial planning has been suggested. The author suggests further research to test the applicability of these indicator measures through real-life case studies of Indian cities based on available environmental information base.
The recent process of urbanisation in the Gulf Cooperation Council Countries (GCCC), including Bahrain, can increase ambient and surface temperatures in newly developed built up areas – the urban heat island (UHI) effect. This study investigates urban expansion in Bahrain over the last few decades and assesses its impact on atmospheric urban heat islands using remote sensing, advanced statistics of weather data and geographical information system (GIS). The study examines how the thermal behaviour of new urban areas is affected by urban elements, with two district models being considered. Numerical modelling is used to assess wind flow, temperatures and heat distribution fluxes within the two models. The assessment shows that mean air temperatures increase within the range of 2 °C–5 °C. The magnitude of the UHI is mainly reinforced by urban activity such as on-going construction processes, shrinkage of green areas and sea reclamation. A comparison of results between the two studied districts reveals that the mean temperature is increased by 2 °C–3 °C in new artificial islands, and by 3 °C–5 °C in deserted urban lands with hot arid conditions. The distribution of urban radiant heat islands is varied and depends largely on the type of land cover and urban surface. Urban grids and structure have a significant impact on the thermal behaviour of newly developed built up areas. Human comfort is improved in the presence of water bodies and green areas.
Constructing and improving urban residential areas is an eternal critical subject in the process of the whole urban development which is connected with a series of challenges and problems. During the past decades, urban residential development has speed up extremely with massive population mobility in cities. The purpose of this study is to propose an integrated approach for sustainability assessment of urban residential development, considering sustainability indicators, housing equilibrium and building visualization. Firstly based on merging DPSIR (Driving Forces, Pressure, State, Impact and Response) framework and Analytic Hierarchy Process (AHP), the indicators were systematized for the sustainability modeling. Due to the urban activities cause impacts not only on local level but also a broader scale, a simulation model, using System Dynamics (SD) methodology, was structured to quantitatively investigate the developmental tendency of the indicators. And then the estimated results were displayed in 2D density maps in ArcGIS and 3D visualization in CityEngine. A real case study was presented for the Stuttgart Region of the state of Baden-Württemberg in Southern Germany and its Plieningen district to experience the usefulness and feasibility of the developed approach. The integration of GIS, SD model and 3D visualization, called GISSD system here, can better explain the interaction and the variation of the sustainability indicators for residential development. Hence it is able to support the Decision Maker to view the sustainable level of urban residential areas more comprehensively.
Urban design is a subject that is concerned with the shape, the surface and its physical arrangement of all kinds of urban elements. Although urban design is a practice process and needs much detailed and multi-dimensional description, the urban designers could only analyse urban space with script and imagination in the past, and only the urban design guideline and some drawing picture were carried out in the traditional design schema. How to improve the quality of urban space effectively and how to express the design schema perfectly are the problems troubling the urban designers for a long time. The 3D city models based spatial analysis gives the possibility of solving these problems. Compared with the traditional applications of 2D GIS in urban planning, the 3D city models based spatial analysis would be more meaningful for the urban designers. The computable analysis models could be constructed under the urban design guideline. Through the integration of analytical models and realistic visualization models, the 3D spatial analysis that is impossible to the 2D GIS can be carried out.Instead of being described with some adjective words, the designing schema and rules can be presented and analyzed in 3D virtual environment. The change of the urban fabric and the building density could be analyzed through the structure analysis. The noise environment, sunshine condition, heat environment, ventilation condition, and pollution condition could be analyzed through the physical quality analysis. The control of the height, the color and the style of the buildings, and the evaluations of the surrounding environment of the squares and the streets are also available based on the visual impact analysis. The analysis of the distribution of different function parts and its proper place are possible through function analysis of urban space.Based on the 3D city models, urban designers can express the design concept clearly. With the analysis functions, it is also possible to control and improve the quality of urban space effectually. There would be a great progress when we design the urban space with an operational 3D analytical system, like Cyber City GIS.
This paper applies a system dynamics model for the sustainable land use and urban development in Hong Kong. The model is used to test the outcomes of development policy scenarios and make forecasts. It consists of five sub-systems including population, economy, housing, transport and urban/developed land, respectively. Two distinctively different development schemes concerning urban population density are simulated by the model and the findings are undertaken to verify the model through comparison with historical data and sensitivity check. The forecast timeframe is then expanded from 40 years to 300 years, providing a simulation period long enough to observe and study the “limits to growth” phenomenon and the impacts on development potential of Hong Kong. The modelling results are directly useful to compare different dynamic consequences brought by various policies and decisions, and are thus of great significance to achieving the goal of sustainable land use.
In this paper, we outline how we have developed a series of technologies that enable planning information to be disseminated
to affected citizens so that professionals and politicians can engage with these stakeholders in realizing more effective
plans. Our main theme is based on the generic idea of the “virtual city” which is conceived in terms of the geography and
geometry of the real city. This is a digital representation using a variety of software and multimedia, made interactively
available over the web. We begin with a brief comment on different types of virtual city and then summarize the key problems
of using such virtualities in public participation, more recently considered as part of the e-democracy movement. We outline
our previous attempts to engage in such online participation in east London for these have been an essential prerequisite
to the development of “Virtual London,” the application reported here which is currently being fashioned for widespread dissemination
of planning information by the Greater London Authority (GLA). We then argue that virtual cities should go well beyond the
traditional conceptions of 3D GIS and CAD into virtual worlds and online design. But we also urge caution in pushing the digital
message too far, showing how more conventional tangible media is always necessary in rooting such models in more realistic
and familiar representations.
The objective of this study is to present a novel tool for predictive modelling of urban growth. The proposed tool, named iCity – Irregular City, extends the traditional formalization of cellular automata (CA) to include an irregular spatial structure, asynchronous urban growth, and a high spatio-temporal resolution to aid in spatial decision making for urban planning. The iCity software tool was developed as an embedded model within a common desktop geographic information system (GIS) with a user-friendly interface to control modelling operations for urban land-use change. This approach allows the model developer to focus on implementing model logic rather than developing an entire stand-alone modelling application. It also provides the model user with a familiar environment in which to run the model to simulate urban growth.
Techniques for modelling urban microclimates and urban block surfaces temperatures are desired by urban planners and architects for strategic urban designs at the early design stages. This paper introduces a simplified mathematical model for urban simulations (UMsim) including urban surfaces temperatures and microclimates. The nodal network model has been developed by integrating coupled thermal and airflow model. Direct solar radiation, diffuse radiation, reflected radiation, long-wave radiation, heat convection in air and heat transfer in the exterior walls and ground within the complex have been taken into account. The relevant equations have been solved using the finite difference method under the Matlab platform. Comparisons have been conducted between the data produced from the simulation and that from an urban experimental study carried out in a real architectural complex on the campus of Chongqing University, China in July 2005 and January 2006. The results show a satisfactory agreement between the two sets of data. The UMsim can be used to simulate the microclimates, in particular the surface temperatures of urban blocks, therefore it can be used to assess the impact of urban surfaces properties on urban microclimates. The UMsim will be able to produce robust data and images of urban environments for sustainable urban design.
For decades urban planning was done by drawing plans and building elaborate models from wood and pasteboard. The Austrian Cities of Graz and Vienna are demonstrating that this is a thing of the past — its three-dimensional (3D) computer simulations derived from information of the digital city map are revolutionizing the planning process.The paper deals with the feasibility and potential benefits of a 3D-city model and covers the following topics: 1.(1) What is a 3D-city model?2.(2) What is it used for?3.(3) Which data is needed for a 3D-city model and where is it derived from?4.(4) How can a 3D-city model be generated on a regular, operational basis?Results of projects carried out in Graz and Vienna will be shown to demonstrate the operational applicability of a 3D-city model.
Observations of wind and temperature in an urban canyon are presented. They form the basis of simple algorithms relating weather conditions above roof-level to those within the street canyon. The temporal development of the spatial distribution of air temperature across the canyon together with the airflow and stability conditions for a complete day is analyzed. The canyon air remains unstable during the nocturnal cooling period in the summer in Japan.
In 2003, Hong Kong was hit by severe acute respiratory syndrome (SARS) from which many people died. The Hong Kong Government subsequently set up a Governmental Team Clean Committee to investigate possible urban design policies. Team Clean charged the task to the Planning Department, HKSAR. In 2003, it initiated a study titled: “Feasibility Study for Establishment of Air Ventilation Assessment (AVA) System.” A number of focused studies were conducted. It eventually led to the technical methodology and guidelines of the air ventilation assessment (AVA) system. Unlike many countries with guidelines for dealing with gust wind problems, AVA is a guideline for weak wind conditions specifically designed to deal with congested urban conditions. The AVA system basically establishes a method for project developers to objectively assess their designs. In 2006, the government of Hong Kong officially adopted the system and required all major publicly funded development projects to undertake the assessment. The scientific and implementation processes leading to the AVA system are reported in this paper.
Geographical information systems (GIS) coupled to 3D visualisation technology is an emerging tool for urban planning and landscape design applications. The utility of 3D GIS for realistically visualising the built environment and proposed development scenarios is much advocated in the literature. Planners assess the merits of proposed changes using visual impact assessment (VIA). We have used Arcview GIS and visualisation software called PolyTRIM from the University of Toronto, Centre for Landscape Research (CLR) to create a 3D scene for the entrance to a University campus. The paper investigates the thesis that to facilitate VIA in planning and design requires not only visualisation, but also a structured evaluation technique (Delphi) to arbitrate the decision-making process.
China has seen the largest human migration in history, and the country's rapid urbanisation has important consequences for public health. A provincial analysis of its urbanisation trends shows shifting and accelerating rural-to-urban migration across the country and accompanying rapid increases in city size and population. The growing disease burden in urban areas attributable to nutrition and lifestyle choices is a major public health challenge, as are troubling disparities in health-care access, vaccination coverage, and accidents and injuries in China's rural-to-urban migrant population. Urban environmental quality, including air and water pollution, contributes to disease both in urban and in rural areas, and traffic-related accidents pose a major public health threat as the country becomes increasingly motorised. To address the health challenges and maximise the benefits that accompany this rapid urbanisation, innovative health policies focused on the needs of migrants and research that could close knowledge gaps on urban population exposures are needed.
The paper reviews virtual environment and GIS technologies available and suitable for virtual city development and urban planning, and focus on the form of 3D virtual city for representing realistic urban environment. The several fields are discussed in terms of their applicability to Web-based applications relating to the urban environment, interactive mapping and collaborative modelling, solid, geometric modelling, photospatial panoramic views, and multi-user virtual worlds. An approach integrating virtual environment and GIS to develop immersive 3d virtual cities is proposed and virtual planning applications are presented. The functionalities can achieve to practice, simulate, visualize and conceptualise issues which relate to a medium-large scale area of urban environments.
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