Rooftop photovoltaics (RPVs) are crucial in achieving energy transition and climate goals, especially in cities with high building density and substantial energy consumption. Estimating RPV carbon mitigation potential at the city level of an entire large country is challenging given difficulties in assessing rooftop area. Here, using multi-source heterogeneous geospatial data and machine learning regression, we identify a total of 65,962 km^2 rooftop area in 2020 for 354 Chinese cities, which represents 4 billion tons of carbon mitigation under ideal assumptions. Considering urban land expansion and power mix transformation, the potential remains at 3-4 billion tons in 2030, when China plans to reach its carbon peak. However, most cities have exploited less than 1% of their potential. We provide analysis of geographical endowment to better support future practice. Our study provides critical insights for targeted RPV development in China and can serve as a foundation for similar work in other countries. Potential rooftop photovoltaic in China affords 4 billion tons of carbon mitigation in 2020 under ideal assumptions, equal to 70% of China’s carbon emissions from electricity and heat. Yet most cities have exploited the potential to a limited degree.
Globally, rapid urbanisation has substantially reduced the amount of viable agricultural land – a food security issue. Food security is bringing a renewed scholarly interest in community gardens. This paper reviews the extent of English academic literature on community gardens, including: who has undertaken the research, where it has been published, the geographical location of the gardens studied, and the various methods used to undertake the research. The characteristics of the community gardens are summarised, including what types of plants are grown, who is involved in the gardens, and who owns the land. The motivations, benefits and limitations of community gardening are also examined. Finally, potential directions for research into community gardens are highlighted. Academic literature on community gardens is dominated by studies investigating gardens in low-income areas with diverse cultural backgrounds. Research based in cities in the USA also dominates the literature. Scholars from a wide diversity of disciplines have examined community gardens but research is mostly concentrated in the social sciences. The natural sciences are notably under-represented, yet they have much to offer including assessing gardening practices to better understand the agro-biodiversity conservation potential of community gardens.
LoRaWAN deployments rely on rough range estimates or simplified propagation models to decide where to place/mount gateways. As a result, operators have limited visibility into how rooftop choice, streets, and building shadowing jointly affect coverage and reliability. This paper addresses the problem of gateway placement in dense urban environments by combining a geometry accurate Digital Twin (DT) with a GPU accelerated ray tracing engine. Existing studies optimize placement on abstract grids or tune models with sparse measurements; few works evaluate LoRaWAN gateways on a full 3D city model using a realistic link budget. In this paper, we develop a DT with ITU radio materials and evaluate eight candidate rooftops for RAK7289 WisGate Edge Pro gateways under a sub-GHz link budget derived from the data sheet. For each rooftop, we obtain Signal-to-Noise Ratios (SNR) on a 5 meter grid, derive robust and edge coverage indicators, and apply a greedy maximum coverage algorithm to rank sites and quantify the benefit of incremental densification. Results show that a single rooftop gateway covers one fifth of the full Sunway twin (i.e., the DT) at a robust SNR threshold, and that six sites still leave large areas of single gateway or out of coverage cells in surrounding residential streets. The findings from this paper shows that DT and ray tracing tools enable network operators to bridge the gap of expensive real-world trials and planning to identify if the planned LoRaWAN gateway is sufficient or additional sites are required.
Marathons are now common ways of seeing cities, yet little is known about how representative their routes are. Using 311 marathon routes across five continents, we compare landmarks and amenities along the course with those elsewhere in the same city, finding that museums are 15.7 times denser near the route and that the median city has about 8.5 times more luxury brands near the route than elsewhere in the city. These patterns persist under perturbed routes with the same start and finish lines: monuments and landmarks, in particular, are more prevalent on the race course than on similar alternative routes, suggesting that marathons function as intentionally selective urban portraits.
The 15-minute city is a powerful planning concept to counter car-dependence by promoting active mobility to amenities and fostering inclusive urban environments. However, this policy has challenges in amenity-poor urban peripheries. Public transport remains underexplored in this discourse despite its role in distant access. Here, we propose a framework that incorporates public transport into the 15-minute city model using openly available data. By comparing Helsinki, Madrid, and Budapest, we demonstrate that multimodal mobility substantially increases access to amenities and enhances socio-spatial integration within a 15-minute reach. Although urban periphery benefit significantly from radial or high-speed public transport lines in their social mixing potential, such lines alone do not improve their access to amenities. These findings underscore the need to optimize polycentric public transport networks that can improve inclusive urban accessibility and complement active mobility in polycentric cities.
This paper brings into proximity and advances geographical engagements with care to propose a new radical care framework for research with minoritised migrants and refugees in the city. Informed by calls for alternative and care- full modes of knowledge production through creative engagements with lived experiences of care and building on recent scholarship on shadow infrastructures of care in cities, it examines how we might attend to the invisibilised modes of caring in the city with migrants and refugees. The paper outlines three dimensions of the framework – knowledges, temporalities and spatialities – as starting points to develop more expansive understandings of care and its radical potential, offering new politics and poetics that challenge and refuse the co-optation of care into the logics of neoliberalism and racial capitalism and to imagine more care- full urban futures.
Objectives
Tackling poverty in all its forms is a key priority for the Scottish Government. However, advances in our understanding of how poverty in Scotland is patterned by its diverse geography is hampered by a lack of robust data at a local area level.
Methods
A systematic data mapping exercise was undertaken to identify suitable datasets with data on a range of poverty outcomes and related proxies, as well as geography indicators. Six datasets were taken forward for descriptive analyses. These included the Households Below Average Income, Children in Low Income Families, Scottish Household Survey, Scottish House Condition Survey, Pupil Census and Understanding Society datasets.
Results
Relative and absolute poverty rates have increased over time in rural areas but remained relatively stable in urban areas at a higher level. In 2023, one in eight children lived in absolute low income families in islands and remote areas compared to one in five in larger cities. Despite this, among children in relative low income households, nearly three in four residing in islands and remote areas live in working families compared to three in five in larger cities. Households in remote rural areas continued to be the most at risk of experiencing fuel poverty and were more likely to report difficulties affording transport costs compared to those in urban areas.
Conclusion
The experience of poverty is different, and has changed in different ways, across different types of rural areas in Scotland. Place-based approaches offer the opportunity to tailor policy interventions to some of the observed localised poverty patterns.
Este artículo identifica las diversas perspectivas de pensamiento que existen al interior de los estudios sobre la informalidad urbana y habitacional en América Latina, así como describir los aportes y críticas que han enfrentado. La metodología incluyó una exhaustiva revisión bibliográfica que permitió trazar temporalmente los momentos de emergencia y periodos de mayor incidencia de cada de una de estas. Complementariamente, se recurre al caso de Chile para ilustrar cómo cada corriente ha surgido en parte por coyunturas sociales y políticas. Se argumenta que estas perspectivas deben ser utilizadas de forma complementaria en vista de la naturaleza multifactorial del fenómeno.
Lucy Temple, Gabriela Viale Pereira, Lukas Daniel Klausner
This short paper represents a systematic literature review that sets the basis for the future development of a framework for digital twin-based decision support in the public sector, specifically for the smart city domain. The final aim of the research is to model context-specific digital twins for aiding the decision-making processes in smart cities and devise methods for defining the policy agenda. Overall, this short paper provides a foundation, based on the main concepts from existing literature, for further research in the role and applications of urban digital twins to assist decision- and policy-making in smart cities. The existing literature analyses common applications of digital twins in smart city development with a focus on supporting decision- and policy-making. Future work will centre on developing a digital-twin-based sustainable smart city and defining different scenarios concerning challenges of good governance, especially so-called wicked problems, in smaller-scale urban and non-urban contexts.
The trend for Urban Air Mobility (UAM) is growing with prospective air taxis, parcel deliverers, and medical and industrial services. Safe and efficient UAM operation relies on timely communication and reliable data exchange. In this paper, we explore Cooperative Perception (CP) for Unmanned Aircraft Systems (UAS), considering the unique communication needs involving high dynamics and a large number of UAS. We propose a hybrid approach combining local broadcast with a central CP service, inspired by centrally managed U-space and broadcast mechanisms from automotive and aviation domains. In a simulation study, we show that our approach significantly enhances the environmental awareness for UAS compared to fully distributed approaches, with an increased communication channel load, which we also evaluate. These findings prompt a discussion on communication strategies for CP in UAM and the potential of a centralized CP service in future research.
Federica Fanelli, Hygor P. M. Melo, Matteo Bruno
et al.
The distribution of urban services reveals critical patterns of human activity and accessibility. Proximity to amenities like restaurants, banks, and hospitals can reduce access barriers, but these services are often unevenly distributed, exacerbating spatial inequalities and socioeconomic disparities. In this study, we present a novel accessibility measure based on the spatial distribution of Points of Interest (POIs) within cities. Using the radial distribution function from statistical physics, we analyze the dispersion of services across different urban zones, combining local and remote access to services. This approach allows us to identify a city's central core, intermediate areas or secondary cores, and its periphery. Comparing the areas that we find with the resident population distribution highlights clusters of urban services and helps uncover disparities in access to opportunities.
The geography of urban innovation in the United States has often been portrayed as dominated by a few large cities. However, emerging perspectives challenge this notion by highlighting the significance of secondary cities for innovation processes. Unfortunately, prevailing narratives and empirical evidence focus on technological invention only, measured by patents. This study aims to reevaluate the geography of urban innovation by considering various phases of the innovation process and incorporating a broader range of innovation types. In addition to conventional patent metrics, this research suggests incorporating trademarks and design rights as complementary data. The findings reveal that large cities still exhibit prominence when examining absolute counts of innovation. Instead, analysing intensities allows the identification of secondary cities that specialise in various innovation activities beyond technological invention only. Overall, the findings provide compelling evidence that urban innovation in the United States is not limited to a few large cities nor is it solely driven by technological invention.
Atchareeya Saisin, Siriporn Somboonboorana, Rajen Singh Laishram
et al.
The border of Moreh town is a major security concern for the Manipur State of India due to its location whereby it shares the border with neighboring Myanmar and the diverse population characteristics. Furthermore, the conflict in Myanmar following a military coup in 2021 heightened regional tensions. It impacted people in the nation and neighboring countries as a result of mass migration fleeing political and economic difficulties. The objective of this article is to examine the security policy-making process and its components in Moreh town, as well as the impact of Myanmar's political crisis on human security, using Securitization Theory as a framework. This study employs qualitative research methodology, primarily relying on secondary documents. According to the findings of this study, the government, both federal and state, is the primary securitizing actor in Moreh town, with other non-actors in dual process of securitization, prioritizing illegal migration as a case study. While insurgencies and other cross-border crimes are also important security issues in the area. As a result of border restrictions and limitations, these issues could have an impact on both national and human security.
Cities. Urban geography, Urbanization. City and country
Water is the most important environmental factor that has a direct influence on the health of
the population and the development of society. There is a clear need to establish the supply of the
population with sufficient quantities of drinking water as a priority direction in state policy and actions
for the health of the population in relation to the environment, in the context of sustainable management
of water resources. Although, currently, the national balance of water reserves - water consumption in
the Republic of Moldova is adequate in relation to the available resources, in the context of climate aridity
and inefficient management of water consumption, this balance may be affected in the future. This
research aims to analyze the dynamics and particularities of water resource abstraction and use in
regional aspect, highlighting the branch structure and some limiting factors in determining the correct
volume of water used. In the period 2003-2022 analyzed in this study, several periods with a maximum
volume of water use (years 2007, 2009, 2020 and 2022) were highlighted as a result of droughts that
affected the whole country. In all 6 development regions, most of the water used is abstracted from
surface sources (85%). At district level, especially in rural localities, water use from underground
sources, including wells and springs, predominates as a result of reduced access to public water supply
systems. About 75% of the total volume of water used is attributed to technological uses. On the right side
of the Dniester River, water is predominantly used for domestic (48%) and agricultural (38%) purposes.
The development of urban-air-mobility (UAM) is rapidly progressing with spurs, and the demand for efficient transportation management systems is a rising need due to the multifaceted environmental uncertainties. Thus, this paper proposes a novel air transportation service management algorithm based on multi-agent deep reinforcement learning (MADRL) to address the challenges of multi-UAM cooperation. Specifically, the proposed algorithm in this paper is based on communication network (CommNet) method utilizing centralized training and distributed execution (CTDE) in multiple UAMs for providing efficient air transportation services to passengers collaboratively. Furthermore, this paper adopts actual vertiport maps and UAM specifications for constructing realistic air transportation networks. By evaluating the performance of the proposed algorithm in data-intensive simulations, the results show that the proposed algorithm outperforms existing approaches in terms of air transportation service quality. Furthermore, there are no inferior UAMs by utilizing parameter sharing in CommNet and a centralized critic network in CTDE. Therefore, it can be confirmed that the research results in this paper can provide a promising solution for autonomous air transportation management systems in city-wide urban areas.
Accurate Urban SpatioTemporal Prediction (USTP) is of great importance to the development and operation of the smart city. As an emerging building block, multi-sourced urban data are usually integrated as urban knowledge graphs (UrbanKGs) to provide critical knowledge for urban spatiotemporal prediction models. However, existing UrbanKGs are often tailored for specific downstream prediction tasks and are not publicly available, which limits the potential advancement. This paper presents UUKG, the unified urban knowledge graph dataset for knowledge-enhanced urban spatiotemporal predictions. Specifically, we first construct UrbanKGs consisting of millions of triplets for two metropolises by connecting heterogeneous urban entities such as administrative boroughs, POIs, and road segments. Moreover, we conduct qualitative and quantitative analysis on constructed UrbanKGs and uncover diverse high-order structural patterns, such as hierarchies and cycles, that can be leveraged to benefit downstream USTP tasks. To validate and facilitate the use of UrbanKGs, we implement and evaluate 15 KG embedding methods on the KG completion task and integrate the learned KG embeddings into 9 spatiotemporal models for five different USTP tasks. The extensive experimental results not only provide benchmarks of knowledge-enhanced USTP models under different task settings but also highlight the potential of state-of-the-art high-order structure-aware UrbanKG embedding methods. We hope the proposed UUKG fosters research on urban knowledge graphs and broad smart city applications. The dataset and source code are available at https://github.com/usail-hkust/UUKG/.