Shadow Accrual Maps: Efficient Accumulation of City-Scale Shadows Over Time

Curio: A Dataflow-Based Framework for Collaborative Urban Visual Analytics

Over the past decade, several urban visual analytics systems and tools have been proposed to tackle a host of challenges faced by cities, in areas as diverse as transportation, weather, and real estate. Many of these tools have been designed through collaborations with urban experts, aiming to distill intricate urban analysis workflows into interactive visualizations and interfaces. However, the design, implementation, and practical use of these tools still rely on siloed approaches, resulting in bespoke systems that are difficult to reproduce and extend. At the design level, these tools undervalue rich data workflows from urban experts, typically treating them only as data providers and evaluators. At the implementation level, they lack interoperability with other technical frameworks. At the practical use level, they tend to be narrowly focused on specific fields, inadvertently creating barriers to cross-domain collaboration. To address these gaps, we present Curio, a framework for collaborative urban visual analytics. Curio uses a dataflow model with multiple abstraction levels (code, grammar, GUI elements) to facilitate collaboration across the design and implementation of visual analytics components. The framework allows experts to intertwine data preprocessing, management, and visualization stages while tracking the provenance of code and visualizations. In collaboration with urban experts, we evaluate Curio through a diverse set of usage scenarios targeting urban accessibility, urban microclimate, and sunlight access. These scenarios use different types of data and domain methodologies to illustrate Curio's flexibility in tackling pressing societal challenges. Curio is available at urbantk.org/curio.

Efficacy of the Stroll Safe Outdoor Fall Prevention Program: A Randomized Controlled Trial

BACKGROUND AND OBJECTIVES

Outdoor falls can negatively affect the independence and well-being of community-dwelling older adults. Although there is some overlap, there are also differences in risk factors for indoor and outdoor falls. There are no existing community-based fall prevention programs that specifically target outdoor fall prevention. To fill this gap, the Stroll Safe program was developed.

RESEARCH DESIGN AND METHODS

A cluster-randomized controlled trial design was used with randomization at the site level. Participants (N = 86) were aged 60 and older, with a history of an outdoor fall or who had a fear of falling outdoors. Eight naturally occurring retirement community program sites were randomly assigned to the treatment or wait list control group. Outcome measures included the Outdoor Falls Questionnaire, the Falls Behavioral Scale for the Older Person, and the Falls Efficacy Scale-International to examine knowledge of risks, safe strategy use, protective behaviors, and fear of falling. An Analysis of Covariance (ANCOVA) was used to compare change scores between groups with covariates included for any initial differences between groups. A linear mixed model was also conducted to account for any clustering effects.

RESULTS

Significant differences (ps < .05) were found between groups for knowledge of outdoor fall risks and safe strategy use. Effect sizes were large (Cohen's d = 1.2-1.9). Results were retained at 6-week follow-up.

DISCUSSION AND IMPLICATIONS

Stroll Safe is effective in improving knowledge of outdoor fall risks and increasing safe strategy use for community mobility. Stroll Safe fills a gap in outdoor fall prevention programs. Clinical Trials Registration Number: NCT03624777.

The Stroll Safe outdoor falls prevention program: Participant experiences in eight community sites

BACKGROUND AND OBJECTIVES

Outdoor falls can negatively impact the quality of life of community-dwelling older adults. Although there are differences in risk factors for indoor and outdoor falls, none of the existing evidence-based fall prevention programs specifically targets outdoors falls. To fill this gap, the Stroll Safe program was developed. The purpose of this study was to explore participant's experiences in the Stroll Safe program RESEARCH DESIGN AND METHODS: In this qualitative study, we conducted focus groups at eight community program sites with Stroll Safe program participants. Thematic analysis, with both deductive and inductive coding were used. Researcher triangulation was employed to increase trustworthiness of the findings RESULTS: Four major themes emerged from the data, including (1) Precipitants of behavioral change, (2) Behavioral change, (3) Program design, and 4) Enjoyment of program experience. Several sub-themes were also uncovered DISCUSSION AND IMPLICATIONS: Although the qualitative findings are consistent with the quantitative findings from the efficacy trial, the results also reveal benefits that were not captured by the quantitative analysis. In addition, the findings related to the influence of the group leader and program design can be used to guide future implementation science studies.

A Comparison of Spatiotemporal Visualizations for 3D Urban Analytics

Recent technological innovations have led to an increase in the availability of 3D urban data, such as shadow, noise, solar potential, and earthquake simulations. These spatiotemporal datasets create opportunities for new visualizations to engage experts from different domains to study the dynamic behavior of urban spaces in this under explored dimension. However, designing 3D spatiotemporal urban visualizations is challenging, as it requires visual strategies to support analysis of time-varying data referent to the city geometry. Although different visual strategies have been used in 3D urban visual analytics, the question of how effective these visual designs are at supporting spatiotemporal analysis on building surfaces remains open. To investigate this, in this paper we first contribute a series of analytical tasks elicited after interviews with practitioners from three urban domains. We also contribute a quantitative user study comparing the effectiveness of four representative visual designs used to visualize 3D spatiotemporal urban data: spatial juxtaposition, temporal juxtaposition, linked view, and embedded view. Participants performed a series of tasks that required them to identify extreme values on building surfaces over time. Tasks varied in granularity for both space and time dimensions. Our results demonstrate that participants were more accurate using plot-based visualizations (linked view, embedded view) but faster using color-coded visualizations (spatial juxtaposition, temporal juxtaposition). Our results also show that, with increasing task complexity, plot-based visualizations perform better in preserving efficiency (time, accuracy) compared to color-coded visualizations. Based on our findings, we present a set of takeaways with design recommendations for 3D spatiotemporal urban visualizations for researchers and practitioners. Lastly, we report on a series of interviews with four practitioners, and their feedback and suggestions for further work on the visualizations to support 3D spatiotemporal urban data analysis.

Study on correlation between shadow patterns and human behaviour in hot, arid cities: a case study of Biskra, Algeria

Although the thermal comfort benefits of shade in warm areas are well known, empirical work on the link between public space use and shade pattern from hot, arid cities remain poorly investigated. The aim of the present study is to investigate the correlation between shadow pattern, outdoor thermal comfort and human behaviour, according to the intensity of public space use by urban dwellers. This work was conducted in an urban area in Biskra City (Algeria), characterized by a hot climate, with an average high temperature 40.2 °C in summer. In situ investigation and behavioural method were applied for behaviour evaluation. Modelling of shadow pattern and assessment of outdoor comfort utilised the physiological equivalent temperature (PET) index and predicted mean vote (PMV). The findings show that the presence of shadow contributes to low PET; as a result, the PET is closely related to shadow in spring than summer while the distribution of people was significantly affected by shadow in summer than spring which affects the city's liveability. Our findings shed the light on the importance of shadow generated by the built environment to enhance comfort and urban liveability in hot and arid cities.

UrbanRama: Navigating Cities in Virtual Reality

Exploring large virtual environments, such as cities, is a central task in several domains, such as gaming and urban planning. VR systems can greatly help this task by providing an immersive experience; however, a common issue with viewing and navigating a city in the traditional sense is that users can either obtain a local or a global view, but not both at the same time, requiring them to continuously switch between perspectives, losing context and distracting them from their analysis. In this article, our goal is to allow users to navigate to points of interest without changing perspectives. To accomplish this, we design an intuitive navigation interface that takes advantage of the strong sense of spatial presence provided by VR. We supplement this interface with a perspective that warps the environment, called UrbanRama, based on a cylindrical projection, providing a mix of local and global views. The design of this interface was performed as an iterative process in collaboration with architects and urban planners. We conducted a qualitative and a quantitative pilot user study to evaluate UrbanRama and the results indicate the effectiveness of our system in reducing perspective changes, while ensuring that the warping doesn't affect distance and orientation perception.

A survey of urban visual analytics: Advances and future directions

Developing effective visual analytics systems demands care in characterization of domain problems and integration of visualization techniques and computational models. Urban visual analytics has already achieved remarkable success in tackling urban problems and providing fundamental services for smart cities. To promote further academic research and assist the development of industrial urban analytics systems, we comprehensively review urban visual analytics studies from four perspectives. In particular, we identify 8 urban domains and 22 types of popular visualization, analyze 7 types of computational method, and categorize existing systems into 4 types based on their integration of visualization techniques and computational models. We conclude with potential research directions and opportunities.

Combining 2D and 3D Visualization with Visual Analytics in the Environmental Domain

The application potential of Visual Analytics (VA), with its supporting interactive 2D and 3D visualization techniques, in the environmental domain is unparalleled. Such advanced systems may enable an in-depth interactive exploration of multifaceted geospatial and temporal changes in very large and complex datasets. This is facilitated by a unique synergy of modules for simulation, analysis, and visualization, offering instantaneous visual feedback of transformative changes in the underlying data. However, even if the resulting knowledge holds great potential for supporting decision-making in the environmental domain, the consideration of such techniques still have to find their way to daily practice. To advance these developments, we demonstrate four case studies that portray different opportunities in data visualization and VA in the context of climate research and natural disaster management. Firstly, we focus on 2D data visualization and explorative analysis for climate change detection and urban microclimate development through a comprehensive time series analysis. Secondly, we focus on the combination of 2D and 3D representations and investigations for flood and storm water management through comprehensive flood and heavy rain simulations. These examples are by no means exhaustive, but serve to demonstrate how a VA framework may apply to practical research.

A Methodological Proposal for the Analysis of Lighting the House Building Façades

Natural lighting is a fundamental element in the habitability of dwellings. However, it is still difficult to calculate its effect on the façades of the buildings in detail, due to the morphological complexity of the property itself, as well as the environment that surrounds it. This study provides a methodological proposal that uses pre-existing open data to extrude buildings by using a GIS procedure. Based on three selected real estate properties with different characteristics in the city of Marbella (Spain), the hours of sunlight received by each building’s façade are calculated, taking into account the digital land model and the digital surface model of the area. The results confirm the usefulness of the method to measure and analyze differences in luminosity between buildings with similar urban characteristics and their surroundings, as well as to record the differences in luminosity between floors and the orientations of the same building at several heights. The methodological proposal opens a path for many applications related to energy efficiency, housing conditions, and property valuation.

Multidimensional Visualization and Processing of Big Open Urban Geospatial Data on the Web

The focus of this research is addressing a subset of the geovisualization (i.e., geographic visualization) challenges identified in the literature, namely multidimensional vector and raster geospatial data visualization. Moreover, the work implements an approach for multidimensional raster geospatial data processing. The results of this research are provided through a geoportal comprised of multiple applications that are related to 3D visualization of cities, ground deformation, land use and land cover and mobility. In a subset of the applications, the datasets handled are considered to be large in volume. The geospatial data were visualized on dynamic and interactive virtual globes to enable visual exploration. The geoportal is available on the web to enable cross-platform access to it. Furthermore, the geoportal was developed employing open standards, free and open source software (FOSS) and open data, most importantly to ensure interoperability and reduce the barriers to access it. The geoportal brings together various datasets, different both in terms of context and format employing numerous technologies. As a result, the existing web technologies for geovisualization and geospatial data processing were examined and exemplary and innovative software was developed to extend the state of the art.

Spatio-Temporal Urban Data Analysis: A Visual Analytics Perspective

Visual analytics systems can greatly help in the analysis of urban data allowing domain experts from academia and city governments to better understand cities, and thus enable better operations, informed planning and policies. Effectively designing these systems is challenging and requires bringing together methods from different domains. In this paper, we discuss the challenges involved in designing a visual analytics system to interactively explore large spatio-temporal data sets and give an overview of our research that combines visualization and data management to tackle these challenges.