Dynamics of the urban lightscape

Dobler, Gregory; Ghandehari, Masoud; Nazari, Rouzbeh; Sharma, Mohit S.; Tafvizi, Arya; Vo, Huy T.; Wurtele, J. S.

doi:10.1016/j.is.2015.06.002

Cited by 69 publications

(57 citation statements)

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“…Recording date(s): Nights can be documented individually, as done here, or in series, as in [12]. In either case, the choice of date(s) is crucial for comparisons among areas and nights, as lighting schedules are likely to change seasonally, with shifts in sunset and sunrise times, as well as during the week, especially between weekand weekend-nights [12].…”

Section: Data Collection: Generating the Time Lapse Videosmentioning

confidence: 99%

“…In either case, the choice of date(s) is crucial for comparisons among areas and nights, as lighting schedules are likely to change seasonally, with shifts in sunset and sunrise times, as well as during the week, especially between weekand weekend-nights [12]. If several locations are to be compared, they will thus ideally all be recorded on the same night(s).…”

Section: Data Collection: Generating the Time Lapse Videosmentioning

confidence: 99%

“…Here, 15-minute segments were used. The on/off times of each unit can be identified manually by repeatedly watching the videos (as done here), or via automation [as in 12]. The on/off times are entered into the database for each unit by indicating its status per time segment of each night ( fig.…”

Section: Classification Of Unitsmentioning

confidence: 99%

“…The research design presented here is complementary to the approach developed by Dobler et al [12] for studying urban rhythms: Both share the same method of data collection and look at on/off times of urban lighting. Significant differences exist, however, in the aims of the research, and, as a result, in terms of perspective and scale: Dobler et al take a broad view of the city from a removed vantage point in order to capture a large number of household and office windows to statistically soundly derive information on the "pulse of the city".…”

Section: Introductionmentioning

confidence: 99%

“…The research design complements existing methods for studying the temporality of lighting (Dobler et al, 2015;Bará et al, 2017): equally based on data collection via time-lapse videos, the design adopts a small-scale, detailed approach by using close-range perspectives to document the on/off patterns of individual light sources as the night progresses. It provides a framework for reading, describing and comparing these temporal profiles of lighting that allows for pinpointing similarities and differences among temporal lighting practices in different places, nights or categories of lighting.…”

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confidence: 99%

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Temporal Profiles of Urban Lighting: Proposal for a research design and first results from three sites in Berlin

Meier

2018

IJSL

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This paper contributes to fundamental research on outdoor lighting practices by presenting and applying a research design for studying their temporal dimension in complex lightscapes such as those of urban centres. The research design complements existing methods for studying the temporality of lighting (Dobler et al., 2015;Bará et al., 2017): equally based on data collection via time-lapse videos, the design adopts a small-scale, detailed approach by using close-range perspectives to document the on/off patterns of individual light sources as the night progresses. It provides a framework for reading, describing and comparing these temporal profiles of lighting that allows for pinpointing similarities and differences among temporal lighting practices in different places, nights or categories of lighting. In the three examined Berlin areas, on/off-times are clustered, resulting in static and dynamic phases of the night. Midnight is a temporal fault-line, after which full illumination ends as portions of the lights are extinguished. Switch-off times and -rates differ among the three areas and, especially, among the four functional types of lighting that were differentiated: infrastructural and commercial units largely remain on all night, while substantial portions of architectural and indoor lighting are switched off, though at fairly different times. This tentatively indicates that, within one geographic and policy context, the purposes to which lights are put are likely more decisive for their temporality than is their concrete locality, but that heterogeneous local temporal lighting cultures may nonetheless exist -even among similar types of areas within the same city. Keywords: urban lightscapes, temporality, dynamics, method, classification IntroductionThe past two decades have seen a consolidation of evidence from a broad range of disciplines that artificial outdoor illumination not only has manifold benefits, but also comes with substantial societal and ecological costs and risks. These are commonly subsumed under the term light pollution, and their long-term effects are hardly foreseeable [1; 2; 3]. The observation that illumination is rapidly expanding in many parts of the world in terms of both geographic spread and intensity [1; 4; 5] lends additional urgency to the matter.As this is a fairly new field of inquiry, knowledge about the underlying lighting practices that structure these developments is still quite limited. A deeper understanding of how much of what types of lighting are used by whom, when, where and why is, however, essential for the establishment of a solid knowledge-base for sustainable planning and policy approaches. Given that the usage of lighting has technical as well as societal dimensions, this demands research in a variety of disciplines; and seeing as lighting practices differ from one context to the next, comparative studies promise to provide insights into local lighting cultures as well as pointers for policy development [6].This paper contributes to a fuller understa...

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Section: Data Collection: Generating the Time Lapse Videosmentioning

confidence: 99%

Section: Data Collection: Generating the Time Lapse Videosmentioning

confidence: 99%

Section: Classification Of Unitsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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Temporal Profiles of Urban Lighting: Proposal for a research design and first results from three sites in Berlin

Meier

2018

IJSL

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Full Field Imaging

Ghandehari

2018

Optical Phenomenology and Applications

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Spatiotemporal evolution of COVID-19 infection and detection within night light networks: comparative analysis of USA and China

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Sousa

2021

Appl Netw Sci

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The spatial distribution of population affects disease transmission, especially when shelter in place orders restrict mobility for a large fraction of the population. The spatial network structure of settlements therefore imposes a fundamental constraint on the spatial distribution of the population through which a communicable disease can spread. In this analysis we use the spatial network structure of lighted development as a proxy for the distribution of ambient population to compare the spatiotemporal evolution of COVID-19 confirmed cases in the USA and China. The Visible Infrared Imaging Radiometer Suite (VIIRS) Day/Night Band sensor on the NASA/NOAA Suomi satellite has been imaging night light at ~ 700 m resolution globally since 2012. Comparisons with sub-kilometer resolution census observations in different countries across different levels of development indicate that night light luminance scales with population density over ~ 3 orders of magnitude. However, VIIRS’ constant ~ 700 m resolution can provide a more detailed representation of population distribution in peri-urban and rural areas where aggregated census blocks lack comparable spatial detail. By varying the low luminance threshold of VIIRS-derived night light, we depict spatial networks of lighted development of varying degrees of connectivity within which populations are distributed. The resulting size distributions of spatial network components (connected clusters of nodes) vary with degree of connectivity, but maintain consistent scaling over a wide range (5 × to 10 × in area & number) of network sizes. At continental scales, spatial network rank-size distributions obtained from VIIRS night light brightness are well-described by power laws with exponents near −2 (slopes near −1) for a wide range of low luminance thresholds. The largest components (104 to 105 km2) represent spatially contiguous agglomerations of urban, suburban and periurban development, while the smallest components represent isolated rural settlements. Projecting county and city-level numbers of confirmed cases of COVID-19 for the USA and China (respectively) onto the corresponding spatial networks of lighted development allows the spatiotemporal evolution of the epidemic (infection and detection) to be quantified as propagation within networks of varying connectivity. Results for China show rapid nucleation and diffusion in January 2020 followed by rapid decreases in new cases in February. While most of the largest cities in China showed new confirmed cases approaching zero before the end of February, most of these cities also showed distinct second waves of cases in March or April. Whereas new cases in Wuhan did not approach zero until mid-March, as of December 2020 it has not yet experienced a second wave of cases. In contrast, the results for the USA show a wide range of trajectories, with an abrupt transition from slow increases in confirmed cases in a small number of network components in January and February, to rapid geographic dispersion to a larger number of components shortly before mobility reductions occurred in March. Results indicate that while most of the upper tail of the network had been exposed by the end of March, the lower tail of the component size distribution has only shown steep increases since mid-June.

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Dynamics of the urban lightscape

Cited by 69 publications

References 12 publications

Temporal Profiles of Urban Lighting: Proposal for a research design and first results from three sites in Berlin

Temporal Profiles of Urban Lighting: Proposal for a research design and first results from three sites in Berlin

Full Field Imaging

Spatiotemporal evolution of COVID-19 infection and detection within night light networks: comparative analysis of USA and China

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