scholarly journals Planarity and Street Network Representation in Urban Form Analysis

2018 ◽  
Author(s):  
Geoff Boeing
Keyword(s):  
Real World ◽  
Travel Behavior ◽  
Urban Form ◽  
Design Patterns ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Two Dimensions ◽  
Street Network ◽  
Form Analysis ◽  
Street Networks

Models of street networks underlie research in urban travel behavior, accessibility, design patterns, and morphology. These models are commonly defined as planar, meaning they can be represented in two dimensions without any underpasses or overpasses. However, real-world urban street networks exist in three-dimensional space and frequently feature grade separation such as bridges and tunnels: planar simplifications can be useful but they also impact the results of real-world street network analysis. This study measures the nonplanarity of drivable and walkable street networks in the centers of 50 cities worldwide, then examines the variation of nonplanarity across a single city. It develops two new indicators - the Spatial Planarity Ratio and the Edge Length Ratio - to measure planarity and describe infrastructure and urbanization. While some street networks are approximately planar, we empirically quantify how planar models can inconsistently but drastically misrepresent intersection density, street lengths, routing, and connectivity.

scholarly journals Planarity and street network representation in urban form analysis

2018 ◽  
Vol 47 (5) ◽  
pp. 855-869 ◽  
Author(s):  
Geoff Boeing
Keyword(s):  
Real World ◽  
Travel Behavior ◽  
Urban Form ◽  
Design Patterns ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Two Dimensions ◽  
Street Network ◽  
Form Analysis ◽  
Street Networks

Models of street networks underlie research in urban travel behavior, accessibility, design patterns, and morphology. These models are commonly defined as planar, meaning they can be represented in two dimensions without any underpasses or overpasses. However, real-world urban street networks exist in three-dimensional space and frequently feature grade separation such as bridges and tunnels: planar simplifications can be useful but they also impact the results of real-world street network analysis. This study measures the nonplanarity of drivable and walkable street networks in the centers of 50 cities worldwide and then examines the variation of nonplanarity across a single city. It develops two new indicators—the Spatial Planarity Ratio and the Edge Length Ratio—to measure planarity and describe infrastructure and urbanization. While some street networks are approximately planar, we empirically quantify how planar models can inconsistently but drastically misrepresent intersection density, street lengths, routing, and connectivity.

scholarly journals Off the Grid... and Back Again? The Recent Evolution of American Street Network Planning and Design

2020 ◽  
Author(s):  
Geoff Boeing
Keyword(s):  
Urban Form ◽  
Design Patterns ◽  
Open Data ◽  
Urban Spatial Structure ◽  
Street Network ◽  
Street Networks ◽  
Planning And Design ◽  
Orientation Order ◽  
Established Relationship ◽  
Intersection Density

This morphological study identifies and measures recent nationwide trends in American street network design. Historically, orthogonal street grids provided the interconnectivity and density that researchers identify as important factors for reducing vehicular travel and emissions and increasing road safety and physical activity. During the 20th century, griddedness declined in planning practice alongside declines in urban form compactness, density, and connectivity as urbanization sprawled around automobile dependence. But less is known about comprehensive empirical trends across US neighborhoods, especially in recent years. This study uses public and open data to examine tract-level street networks across the entire US. It develops theoretical and measurement frameworks for a quality of street networks defined here as griddedness. It measures how griddedness, orientation order, straightness, 4-way intersections, and intersection density declined from 1940 through the 1990s while dead-ends and block lengths increased. However, since 2000, these trends have rebounded, shifting back toward historical design patterns. Yet, despite this rebound, when controlling for topography and built environment factors all decades post-1939 are associated with lower griddedness than pre-1940. Higher griddedness is associated with less car ownership—which itself has a well-established relationship with vehicle kilometers traveled and greenhouse gas emissions—while controlling for density, home and household size, income, jobs proximity, street network grain, and local topography. Interconnected grid-like street networks offer practitioners an important tool for curbing car dependence and emissions. Once established, street patterns determine urban spatial structure for centuries, so proactive planning is essential.

scholarly journals Automated Street Network Analysis for Urban Planners with OSMnx

2018 ◽  
Author(s):  
Geoff Boeing
Keyword(s):  
Travel Behavior ◽  
Urban Form ◽  
Network Modeling ◽  
Street Network ◽  
Urban Networks ◽  
Street Networks ◽  
Household Travel ◽  
Intersection Density ◽  
Block Sizes ◽  
Free Open Source

Street network modeling has become ubiquitous in urban planning for analyzing transportation infrastructure, household travel behavior, accessibility and social equity, location centrality, walkability, and indicators of the urban fabric including block sizes, intersection density, and connectivity. However, straightforward, scalable tools for professional planners to automatically acquire and analyze detailed street networks have been few and far between. OSMnx offers an easier way. It is a new, free, open-source tool that allows anyone to download walkable, drivable, or bikeable urban networks from OpenStreetMap for any city name, address, or polygon in the world, then automatically analyze and visualize them. OSMnx democratizes these data and methods to help technical and non-technical planners use OpenStreetMap data to model urban form, circulation, accessibility, and resilience.

Spatial phenomenology requires potential illumination

2003 ◽  
Vol 26 (4) ◽  
pp. 425-426
Author(s):  
James A. Schirillo
Keyword(s):  
Visual System ◽  
Spatial Model ◽  
Dimensional Space ◽  
Color Constancy ◽  
Three Dimensional ◽  
Two Dimensions ◽  
Three Dimensional Space

Collapsing three-dimensional space into two violates Lehar's “volumetric mapping” constraint and can cause the visual system to construct illusory transparent regions to replace voxels that would have contained illumination. This may underlie why color constancy is worse in two dimensions, and argues for Lehar to revise his phenomenal spatial model by putting “potential illumination” in empty space.

The Development of Pompeii’s Urban Street Network

2017 ◽  
Author(s):  
Eric E. Poehler
Keyword(s):  
Urban Form ◽  
Formal Analysis ◽  
Street Network ◽  
Urban Street ◽  
Street Networks ◽  
The City ◽  
Present Understanding

Chapter 2 explores the present understanding of Pompeii’s evolution by disassembling the apparent patchwork of grids across the city and reconsiders the presumed awkwardness in their adhesion. To do this, the traditional tools of formal analysis—street alignments and block shapes—are employed with and critiqued by the stratigraphic evidence recovered in the last three decades of excavation below the 79 CE levels. The result is an outline of the development of Pompeii’s urban form as a series of street networks: from the archaic age, through the period of the “hiatus” of the fifth and fourth centuries BCE, to a reorganization of the city’s space so profound that it can genuinely be considered a refoundation, and finally to the adjustments of a refounded city in the Colonial, Augustan, and post-earthquake(s) periods.

scholarly journals Extended Particle-Aided Unscented Kalman Filter Based on Self-Driving Car Localization

2020 ◽  
Vol 10 (15) ◽  
pp. 5045 ◽  
Author(s):  
Ming Lin ◽  
Byeongwoo Kim
Keyword(s):  
Kalman Filter ◽  
Real World ◽  
Gaussian Noise ◽  
Unscented Kalman Filter ◽  
Three Dimensional ◽  
Two Dimensions ◽  
Localization Problem ◽  
Simulation Results ◽  
Non Gaussian ◽  
Self Driving Cars

The location of the vehicle is a basic parameter for self-driving cars. The key problem of localization is the noise of the sensors. In previous research, we proposed a particle-aided unscented Kalman filter (PAUKF) to handle the localization problem in non-Gaussian noise environments. However, the previous basic PAUKF only considers the infrastructures in two dimensions (2D). This previous PAUKF 2D limitation rendered it inoperable in the real world, which is full of three-dimensional (3D) features. In this paper, we have extended the previous basic PAUKF’s particle weighting process based on the multivariable normal distribution for handling 3D features. The extended PAUKF also raises the feasibility of fusing multisource perception data into the PAUKF framework. The simulation results show that the extended PAUKF has better real-world applicability than the previous basic PAUKF.

scholarly journals Understanding Chinese Urban Form: The Universal Fractal Pattern of Street Networks over 298 Cities

2020 ◽  
Vol 9 (4) ◽  
pp. 192 ◽  
Author(s):  
Ding Ma ◽  
Renzhong Guo ◽  
Ye Zheng ◽  
Zhigang Zhao ◽  
Fangning He ◽  
...  
Keyword(s):  
Urban Form ◽  
Physical Structure ◽  
Urban Morphology ◽  
Street Network ◽  
Urban Street ◽  
Street Networks ◽  
Topological Measures ◽  
Heavy Tailed ◽  
Definition Of ◽  
Almost All

Urban form can be reflected by many city elements, such as streets. A street network serves as the backbone of a city and reflects a city’s physical structure. A street network’s topological measures and statistical distributions have been widely investigated in recent years, but previous studies have seldom characterized the heavy-tailed distribution of street connectivities from a fractal perspective. The long-tail distribution of street connectivities can be fractal under the new, third definition: a set or pattern is fractal if the scaling of far more small things than large ones recurs at least twice. The number of recurred scaling patterns of far more less-connected streets than well-connected ones greatly helps in measuring the scaling hierarchy of a street network. Moreover, it enables us to examine the potential fractality of urban street networks at the national scale. In this connection, the present study aims to contribute to urban morphology in China through the investigation of the ubiquity of fractal cities from the lens of street networks. To do this, we generate hundreds of thousands of natural streets from about 4.5 million street segments over 298 Chinese cities and adopted power-law detection as well as three fractal metrics that emerged from the third definition of fractal. The results show that almost all cities bear a fractal structure in terms of street connectivities. Furthermore, our multiple regression analysis suggests that the fractality of street networks is positively correlated with urban socioeconomic status and negatively correlated with energy consumption. Therefore, the fractal metrics can be a useful supplement to traditional street-network configuration measures such as street lengths.

scholarly journals An overview of augmented visualization: observing the real world as desired

2018 ◽  
Vol 7 ◽  
Author(s):  
Shohei Mori ◽  
Hideo Saito
Keyword(s):  
Real World ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Open Problems ◽  
The Real ◽  
Real Objects ◽  
Point Image ◽  
Set Up ◽  
Background Image

Over 20 years have passed since a free-viewpoint video technology has been proposed with which a user's viewpoint can be freely set up in a reconstructed three-dimensional space of a target scene photographed by multi-view cameras. This technology allows us to capture and reproduce the real world as recorded. Once we capture the world in a digital form, we can modify it as augmented reality (i.e., placing virtual objects in the digitized real world). Unlike this concept, the augmented world allows us to see through real objects by synthesizing the backgrounds that cannot be observed in our raw perspective directly. The key idea is to generate the background image using multi-view cameras, observing the backgrounds at different positions and seamlessly overlaying the recovered image in our digitized perspective. In this paper, we review such desired view-generation techniques from the perspective of free-view point image generation and discuss challenges and open problems through a case study of our implementations.

3D Navigational Path Planning

Robotica ◽  
1990 ◽  
Vol 8 (3) ◽  
pp. 195-205 ◽  
Author(s):  
T.M. Rao ◽  
Ronald C. Arkin
Keyword(s):  
Path Planning ◽  
Mobile Robot ◽  
Recent Literature ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Two Dimensions ◽  
Polyhedral Objects ◽  
3D Surfaces ◽  
Three Dimensional Space

SUMMARYThe problem of path planning for a mobile robot has been studied extensively in recent literature. Much of the work in this area is devoted to the study of path planning for an earth-bound robot in two dimensions. In this paper, we explore the problem for a robot that can fly in three dimensional space or crawl on 3D surfaces or use a combination of both. We assume that the obstacles can be modeled as polyhedral objects.

Young Children's Painting of the Sky and the Ground

1990 ◽  
Vol 13 (1) ◽  
pp. 49-65 ◽  
Author(s):  
Vicky Lewis
Keyword(s):  
Young Children ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Two Dimensions ◽  
Air Gap ◽  
Age Range ◽  
Three Dimensional Space

Young children often leave a gap between the sky and the horizon in their drawings and paintings. Study 1 examined the landscape paintings of a group of 45 7-10-year-old children and found the children leaving an air gap to be significantly younger than those painting the sky to the horizon. In addition the omission of the air gap was associated with the use of devices to represent three-dimensional space in two dimensions. In Study 2 a group of 7-8-year old chldren painted landscapes on two occasions separated by 7-7.5 months. This study suggested that there are a series of stages between leaving a gap and painting the sky to meet the horizon. It is concluded that painting the sky to meet the horizon may be one of several strategies for representing three-dimensional space, which develops over the age range studied.

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