Geography Of Cities Research Articles

An experiment with the minor geographies of major cities: Infrastructural relations among the fragments

Research on urban water infrastructures has seldom reached across the Global North-South divide owing to their apparent developmental incommensurability. Yet, the universalising tendencies of urban theory has meant that cities of the Global South are often deemed to have ‘fragmented’ infrastructures or incomplete circulations in implicit comparison to the northern infrastructural ideal. So, in order to truly ‘world’ the study of infrastructures and cities, it is important to go beyond these dominant paradigms and attend to how infrastructures actually work and what socio-technical implications they have in cities of the Global South and North. Building on these provocations, this paper places the water infrastructures of two ‘most different cities’– Chennai, India and London, UK – alongside each other in ‘experimental comparison’, where the aim is not to arrive at paradigmatic urban theory but to highlight heterogeneity and excavate themes for further critical thinking on each case. This paper will delineate the dialogic and reflexive method of research and analysis adopted, tracing how it led to the practice of ‘minor theory’, which focuses on processes that do not find expression in dominant universalising analyses. Here, minor theory is mobilised towards challenging dominant or major constructs about each city and across cities, while amplifying urban multiplicities and enabling a deeper engagement with infrastructure making in the Global South and North, thus expanding urban studies’ toolbox of critical thinking.

Integration of 3DGIS and BIM and its application in visual detection of concealed facilities

ABSTRACT The multi-level modeling technology of Building Information Modeling (BIM), combined with Three-dimensional Geographic Information System (3DGIS) macro-scene visualization technology and location information, can realize the transmission of decentralized information from various disciplines to multi-disciplinary collaborative information sharing services. It can be applied independently for the whole life cycle, which plays a positive role in reducing the cost and improving the efficiency of engineering planning, design, construction, operation, and maintenance. In this paper, the data integration and function integration methods of 3DGIS and BIM are designed. In order to avoid the breaking problems caused by attribute information loss and excessive simplification in the process of BIM data integration, the attribute mapping between 3DGIS and BIM based on Industry Foundation Classes (IFC) and City Geography Markup Language (CityGML) and the data simplification method considering the geometric characteristics of BIM are designed. By setting the relevant preconditions and thresholds of patch merging, on the premise of maintaining the structural characteristics of BIM data surface, reduce the amount of model data to improve the efficiency of BIM data loading, rendering and display effect in 3D geospatial scene. Through the data and function integration of 3DGIS and BIM, we can effectively manage the data of large-scale model, and calculate and obtain the geospatial location and direction of key parts of buildings through the coordinate transformation of BIM, which can effectively assist the rapid and accurate positioning of BIM in virtual 3D scene and expand the visualization ability of 3DGIS. By effectively integrating 3DGIS and BIM, this paper gives full play to the spatial management advantages of 3DGIS and the component management advantages of BIM. The rationality and operability of the method are verified by its application in the operation and maintenance management project of concealed facilities in actual buildings.

Assessing the role of geographic context in transportation mode detection from GPS data

The increasing availability of health monitoring devices and smartphones has created an opportunity for researchers to access high-resolution (spatial and temporal) mobility data for understanding travel behavior in cities. Although information from GPS data has been used in several studies to detect transportation modes, there is a research gap in understanding the role of geographic context in transportation mode detection. Integrating the geography in which mobility occurs, provides context clues that may allow models predicting transportation modes to be more generalizable. Our goals are first, to develop a data-driven modeling framework for transportation mode detection using GPS mobility data along with geographic context, and second, to assess how model accuracy and generalizability varies upon adding geographic context. To this extent we extracted features from raw GPS mobility data (speed, altitude, turning angle and net displacement) and integrated context in the form of geographic features to classify active (i.e. walk/bike), public (i.e. bus/train), and private (i.e. car) transportation modes in three different Canadian cities - Montreal, St. Johns, and Vancouver. To assess the role of integrating geographic context in mode detection, we adopted two different modeling approaches – generalized and context-specific, and compared results using random forests, extreme gradient boost, and multilayer perceptron classifiers. Our results indicate that for context-specific models the highest classification accuracy improved by 64% for Montreal, by 74% for St. John's and by 77% for Vancouver compared to the generalized model. We also found that the multilayer perceptron (96%) achieved the highest classification accuracy upon adding contextual variables compared to random forests (94.6%) and extreme gradient boost (93.3%) classifier. Our study highlights that adding contextual information specific to a city's geography can improve the predictive accuracy of transportation mode detection models, however, in case of limited knowledge about the geographic setting of a study area, a generalized model combining GPS data from several cities may still be useful for predicting modes from trip data.

Getting the Hell Over Manhattan

Getting the Hell Over Manhattan

Show me the money: Income inequality and segregation in UK cities

AbstractThe social geography of cities is argued to be changing globally; rising economic inequality is associated with increasing segregation. Yet, income inequality has been predominantly mobilised through national and regional imaginaries. In cities, a number of factors such as the normative policy motivation to intervene in ‘disadvantaged’ neighbourhoods, have led to (concentrations of) poverty becoming prioritised in empirical studies of household income. This paper addresses a gap in understanding the relationship between local income inequality and the segregation of high‐income households at the urban and neighbourhood scales in England and Wales. The results highlight that wealthier cities and districts (Cambridge, Winchester, and Rushcliffe in the Nottingham conurbation) have higher income inequality (Gini), but are less segregated (Index of Dissimilarity). Lower average income cities tend to be more segregated, due to self‐segregation of high‐income households into ‘pockets of affluence.’ These results confirm that high‐income households are the most segregated group in our sample, consistent with trends in global urban segregation patterns. The research also highlights just how prevalent low income is in urban neighbourhoods, making the case for high income as the designated minority population in segregation studies. In our detailed case study of Nottingham, income homogeneity is typical of areas with high deprivation. Neighbourhoods with a high Gini coefficient could be described as mixed income: the Gini is raised by the presence of high‐income households in urban neighbourhoods. We argue that the Gini therefore offers potential as an indicator of social mix in urban studies. These results are based on an experimental household income dataset released by the Office of National Statistics, with analysis of all core cities in England and Wales, alongside Derby, Leicester, Cambridge, Southampton, and Winchester, followed by a detailed case study of Nottingham (UK) and its extended suburban boundary.

3D city model for monitoring flash flood risks in Salalah, Oman

This paper investigates the issues and challenges in using a 3D city model for monitoring flash flood risks in Salalah (Oman) designed using the City Geography Markup Language (CityGML) standards version 2.0. The investigation was made based on the fact that 2D and 2.5D GIS solutions cannot analyse flood complex problems inside the urban area. Hence, the study sought to reduce time and effort for the decision-makers by proposing a 3D city model for flood risk management. The study used geospatial tools and databases such as ArcGIS, Watershed Modelling System (WMS), FME, PostgreSQL-PostGIS, and 3D City Database (3DCityDB) to generate the 3D model and to test the capability of establishing a unified geospatial data structure including the 3D city objects, hydrological data, and geological data. The findings showed the importance of addressing flood risks data and arranging it in the 3D geodatabase. It was also revealed that establishing a 3D city model based on the CityGML standard requires homogenised definitions and standards for city objects (surface and subsurface) as well as hydrological data.

Where do Smart Cities grow? The spatial and socio-economic configurations of smart city development

In the last decade, a number of smart city initiatives have flourished around the world. While the literature is ripe with descriptions of those projects and pioneering cities, there is far less systematic research on why some cities are more advanced than others. As single locating entities, cities are posited to have strong geographic rootedness. Hence, spatial and socio-economic context, considered as the main stimulant of organizational innovation, can be particularly important for cities. We investigate 22 Swiss cities with smart city projects and use fuzzy-set Qualitative Comparative Analysis to determine the configuration of conditions that make some cities more advanced than others in their smart city development. Results indicate that a configuration of high share of service sector, presence of research institutions and high urban density is sufficient for the outcome, whereas population size, new residential development and participation to international networks appear as less important. By providing insights into the spatial and socio-economic underpinnings of smart city development, the study contributes to the understanding of the geographies of smart cities.

Bottom‐up estimation of material stocks and flows in Toronto's road network

AbstractImproving resource efficiency is critical to reduce the environmental impacts of constructing and maintaining the built environment. A growing body of research has been investigating where and for what purposes construction materials are consumed in cities. Much of this existing research relies on archetypes to simplify the analysis of the large number of structures, and city‐scale bottom‐up material stock assessments mostly examine buildings to the exclusion of other urban structures. In this research we examine the effectiveness of pavement archetypes compared to spatially disaggregate pavement material data from a municipal pavement management database for stock estimation and find that the use of archetypes can lead to asymmetric estimation errors (i.e., variability in prediction error among materials and across the city's geography). We use Toronto's road network as a case study and estimate the stocks of concrete, asphalt, and granular materials. The stock of materials is unevenly distributed, in terms of both material type (uneven distribution of concrete vs. asphalt) and when normalized by area and population. In general, the use of archetypes tends to obscure spatial variability in material use, even across a relatively limited geographical area like Toronto and relatively consistent product like roads. We argue that the uncertainty inherent in the use of archetypes is significant and should be accounted for in bottom‐up urban material flow analysis, that governments are in a unique position to provide high quality data for study, and that efforts should be made to capture, collate, and share this information more widely.

IFC AND CITYGML SEMANTIC TRANSFORMATION FOR 3D GIS

Building information modelling (BIM) and geographical information systems (GIS) domains immensely contribute to a digital representation of architectural and environmental bodies respectively. BIM is endorsed in order to enhance the Architecture Engineering and Construction (AEC) industry process to save time, cost and speed up the project, and more so, to minimise the frequent requests of information by the stakeholders within the industry. On the other hand, the Geographic Information System (GIS) has been increasingly used to generate detailed 3D data, geolocation and spatial analysis. Both BIM and GIS provide 3D data for the development of 3D city models, digital twin, smart city, AEC etc. However, there are significant diverse between the two in terms of their characteristics, scope of interest and focus that makes it difficult to easily be achieved. The amalgamation of the two worlds provides a clear picture of a built environment based on data (geometry and semantics) integration, which reinforces the enhancement of the three-dimensional (3D) applications in general into the digital world. This paper presents a methodology that semantically integrates the two worlds through their standards that is the Industry Foundation Classes (IFC) which is an open standard, selected because it is the typical free standard to exchange data in the BIM world and City Geography Markup Language (CityGML) is the most leading 3D city model standard in 3D GIS. This is carried out by performing a semantic mapping between the two standards, converting the encoding that the two standards use from STEP in IFC(BIM) to XML in CityGML (3D GIS), by providing a basic implementation created using Python to combine the above tasks.

A Semantics-Based Approach for Simplifying IFC Building Models to Facilitate the Use of BIM Models in GIS

Using solid building models, instead of the surface models in City Geography Markup Language (CityGML), can facilitate data integration between Building Information Modeling (BIM) and Geographic Information System (GIS). The use of solid models, however, introduces a problem of model simplification on the GIS side. The aim of this study is to solve this problem by developing a framework for generating simplified solid building models from BIM. In this framework, a set of Level of Details (LoDs) were first defined to suit solid building models—referred to as s-LoD, ranging from s-LoD1 to s-LoD4—and three unique problems in implementing s-LoDs were identified and solved by using a semantics-based approach, including identifying external objects for s-LoD2 and s-LoD3, distinguishing various slabs, and generating valid external walls for s-LoD2 and s-LoD3. The feasibility of the framework was validated by using BIM models, and the result shows that using semantics from BIM can make it easier to convert and simplify building models, which in turn makes BIM information more practical in GIS.

Universities and urban social structure: gentrification, studentification, and youthification in five United States legacy cities

ABSTRACT Anchor institutions, including universities, are often instrumentalized to spur revitalization in shrinking or declining cities. Yet universities’ implications for the social geographies of legacy cities remain understudied. We examine links between universities and gentrification, alongside “studentification” resulting from the concentration of students and “youthification” due to the concentration of young adults, in five legacy city Metropolitan Statistical Areas in the United States in 1980 and 2016 using data from the Census and American Community Survey. We identify differences in the relationships between these processes across the MSAs, reflecting to varying degrees patterns previously observed in strong-market cities. Proximity to universities is more closely associated with studentification and youthification over time, with the latter emerging after 1980, rather than conventional gentrification. We also identify racial dimensions of studentification and youthification processes. We highlight the broader social implications of urban universities, and the salience of studentification and youthification in new contexts.

A novel geographical research agenda on Silk Road urbanisation

AbstractThe New Silk Road, also called China's Belt and Road Initiative (BRI), is the largest single infrastructure project since the Marshall Plan and an exemplar of infrastructure‐led development of a scope and scale with no precedent in modern history. The project is estimated to cost up to US$8 trillion, involve 130 countries and impact more than 65% of the world's population. Through novel combinations of infrastructure and industrial projects with investments in the urban built environment, the BRI is transforming urban space across the global South and North altering the social and urban geographies of cities at a historically unparalleled scale. Nonetheless, its role in driving global urban transformation remains fundamentally underexplored. Relevant geographical research is scarce and comparative approaches focusing on cities are in their infancy, leading researchers to talk about an ‘anti‐urban’ bias in contemporary BRI scholarship that prevents an in‐depth understanding of the initiative's true scope. This paper introduces the novel concept of Silk Road urbanisation and puts forward the need for a new research agenda that has the potential to transform geographical and urban research on infrastructure‐led development, urban transformation and inequality.

A CATEGORY-THEORY APPROACH FOR CONSTRUCTION ONTOLOGIES IN SUBSURFACE MASS TRANSIT

Abstract. The construction and expansion of subway systems represents an important step towards better livability conditions in a rapidly urbanizing world. However, underground construction has not benefited from well-established ontologies of semantic and geometric representation, such as Building Information Modelling (which is used for standalone structures) and City Geography Markup Language (which is designed for continuous urban elements). To bridge that gap, this paper proposes a novel and highly flexible means to underpin a relevant ontology. The approach uses the ontology log, or olog, a model of knowledge representation based on Category Theory. In an olog, dependencies between objects are restricted to functional relationships (for every object there is a unique correspondence). This robust mathematical formulation allows for a more flexible, yet also informative and user-readable model of the studied entities. In this paper, the olog’s usability is demonstrated through the ontological representation of common items in the fare-control areas of two New York City metro stations. Ologs are shown to capture similar underlying structures both across different stations and within the same station. Importantly, the olog allows for further generalization to incorporate pre-existing data, as well as being a transferable framework for conceptualizations of other metro systems.

CityGML urban model generation using national public datasets for flood damage simulations: A case study in Korea

Managing information at city level has become increasingly important owing to the introduction of smart cities and the increasing severity of disasters due to climate change. A data collection framework, model construction, and information management must be established to systematically manage information at the city level. This study developed an urban model generation method using detailed attributes within the City Geography Markup Language (CityGML), a standard data schema for 3D representation of cities based on different types of publicly available information within Korea. The generated model was used to develop a method for simulating flooding status, degree of flooding, and level of building damage after heavy rainfall, in Korea. Furthermore, we developed a method to estimate the loss of human life and property damage by combining the results of the flood analysis with the city model. The proposed methodology supports the creation of standard-based models for flood analysis and exhibits strong interoperability for application to different areas of analysis.

Towards a post-COVID geography of economic activity: Using probability spaces to decipher Montreal's changing workscapes.

In March 2020, many workers were suddenly forced to work from home. This brought into stark relief the fact that urban economic activity is no longer attached to specific workplaces. This detachment has been analysed in research on organisations and workers, but has not yet been incorporated into concepts used to document and plan the economic geography of cities. In this article, three questions are explored by way of an original survey: first, how can a shift in the location of economic activity be measured at the urban scale whilst incorporating the idea that work is not attached to a single location? Second, what is the nature of the shift that occurred in March 2020? Third, what does this tell us about concepts that have underpinned the study of urban economic form by geographers and planners? Applying concepts developed in organisation studies and sociology, we operationalise the idea that economic activity happens across multiple spaces: it occurs within a probability space, and since March 2020 it has shifted within this space. To better understand and interpret the longer-term impact of this shift on cities – downtowns in particular – we draw upon interviews with people working from home.

Using 3D CityGML for the Modeling of the Food Waste and Wastewater Generation-A Case Study for the City of Montréal.

The paper explains a workflow to simulate the food energy water (FEW) nexus for an urban district combining various data sources like 3D city models, particularly the City Geography Markup Language (CityGML) data model from the Open Geospatial Consortium, Open StreetMap and Census data. A long term vision is to extend the CityGML data model by developing a FEW Application Domain Extension (FEW ADE) to support future FEW simulation workflows such as the one explained in this paper. Together with the mentioned simulation workflow, this paper also identifies some necessary FEW related parameters for the future development of a FEW ADE. Furthermore, relevant key performance indicators are investigated, and the relevant datasets necessary to calculate these indicators are studied. Finally, different calculations are performed for the downtown borough Ville-Marie in the city of Montréal (Canada) for the domains of food waste (FW) and wastewater (WW) generation. For this study, a workflow is developed to calculate the energy generation from anaerobic digestion of FW and WW. In the first step, the data collection and preparation was done. Here relevant data for georeferencing, data for model set-up, and data for creating the required usage libraries, like food waste and wastewater generation per person, were collected. The next step was the data integration and calculation of the relevant parameters, and lastly, the results were visualized for analysis purposes. As a use case to support such calculations, the CityGML level of detail two model of Montréal is enriched with information such as building functions and building usages from OpenStreetMap. The calculation of the total residents based on the CityGML model as the main input for Ville-Marie results in a population of 72,606. The statistical value for 2016 was 89,170, which corresponds to a deviation of 15.3%. The energy recovery potential of FW is about 24,024 GJ/year, and that of wastewater is about 1,629 GJ/year, adding up to 25,653 GJ/year. Relating values to the calculated number of inhabitants in Ville-Marie results in 330.9 kWh/year for FW and 22.4 kWh/year for wastewater, respectively.

Mean Streets: Tracking the Dispositives of Address(es) with China Miéville’s “Reports of Certain Events in London”

Abstract Miéville’s short story stands out for its perhaps experimental, perhaps old-fashioned form: the story’s first-person narrator adopts, in nineteenth-century fashion, the persona of an editor and presents both his own view on the ‘events’ in question and a number of mock documents he has allegedly been sent. Readers are encouraged to piece together the story elements – events and characters – from postcards, minutes of a meeting, memos, personal letters, and tables. Typographically distinct and juxtaposed rather than narratively linked, these text fragments suggest internal conflicts in a group of people who track rogue streets – streets that change their location spontaneously and wreak havoc on the geographical and the political order of cities. It is no coincidence that a mix-up of names and addresses is the starting point of the story; the story’s ending hints at the consequences of having or not having a fixed address. My contribution examines Miéville’s use of the short story form in the context of fantastic literature. Following suggestions of Miéville’s “The Conspiracy of Architecture” (1998), the foregrounding of formal and quasi-material aspects of organising and mediating knowledge is read as an engagement with the power/knowledge dispositives made up of discursive ordering principles as well as city planning and city geography.

Seismic Damage Semantics on Post-Earthquake LOD3 Building Models Generated by UAS

In a post-earthquake scenario, the semantic enrichment of 3D building models with seismic damage is crucial from the perspective of disaster management. This paper aims to present the methodology and the results for the Level of Detail 3 (LOD3) building modelling (after an earthquake) with the enrichment of the semantics of the seismic damage based on the European Macroseismic Scale (EMS-98). The study area is the Vrisa traditional settlement on the island of Lesvos, Greece, which was affected by a devastating earthquake of Mw = 6.3 on 12 June 2017. The applied methodology consists of the following steps: (a) unmanned aircraft systems (UAS) nadir and oblique images are acquired and photogrammetrically processed for 3D point cloud generation, (b) 3D building models are created based on 3D point clouds and (c) 3D building models are transformed into a LOD3 City Geography Markup Language (CityGML) standard with enriched semantics of the related seismic damage of every part of the building (walls, roof, etc.). The results show that in following this methodology, CityGML LOD3 models can be generated and enriched with buildings’ seismic damage. These models can assist in the decision-making process during the recovery phase of a settlement as well as be the basis for its monitoring over time. Finally, these models can contribute to the estimation of the reconstruction cost of the buildings.

Towards Effective BIM/GIS Data Integration for Smart City by Integrating Computer Graphics Technique

The development of a smart city and digital twin requires the integration of Building Information Modeling (BIM) and Geographic Information Systems (GIS), where BIM models are to be integrated into GIS for visualization and/or analysis. However, the intrinsic differences between BIM and GIS have led to enormous problems in BIM-to-GIS data conversion, and the use of City Geography Markup Language (CityGML) has further escalated this issue. This study aims to facilitate the use of BIM models in GIS by proposing using the shapefile format, and a creative approach for converting Industry Foundation Classes (IFC) to shapefile was developed by integrating a computer graphics technique. Thirteen building models were used to validate the proposed method. The result shows that: (1) the IFC-to-shapefile conversion is easier and more flexible to realize than the IFC-to-CityGML conversion, and (2) the computer graphics technique can improve the efficiency and reliability of BIM-to-GIS data conversion. This study can facilitate the use of BIM information in GIS and benefit studies working on digital twins and smart cities where building models are to be processed and integrated in GIS, or any other studies that need to manipulate IFC geometry in depth.

An Evaluation for the Efficiency of Educational Services at Al-Fallujah City at 2019-2020 (A Study in Geography of Cities)

Educational services are one of the pillars of the social andcultural development, the study dealt with the efficiency of the educational governmental services at AL-Fallujah city in 2019-2020 depending mainly on the empirical study and analytical approach, by many planned standards, and local Iraqi educational indicators and their application to check its efficiency and suitability to meet the needs of its people. After examining the educational services and its geographical distribution as well as the comprehensive survey of all the governmental kindergartens and schools that fell on the visible satellite (WorldView-3), accuracy(30cm), extension(JPEG) in 2017 and the empirical study in August 2020, it was generally noticed that the averages of the schools and classes of the students are higher than the specific standar. In addition, the education suffers from a shortage in the school’s buildings which caused an overcrowding, duality and increasment in the number of students in the class that it is in return block the process of proper education. This is can be due not only for a decreasment in its number but also for the lack in planning for future which overlooks the increase in the number of people. Then, the researcher has reached for certain results and recommendations.