Mapping Lightscapes: Spatial Patterning of Artificial Lighting in an Urban Landscape

Abstract

Artificial lighting is strongly associated with urbanisation and is increasing in its extent, brightness and spectral range. Changes in urban lighting have both positive and negative effects on city performance, yet little is known about how its character and magnitude vary across the urban landscape. A major barrier to related research, planning and governance has been the lack of lighting data at the city extent, particularly at a fine spatial resolution. Our aims were therefore to capture such data using aerial night photography and to undertake a case study of urban lighting. We present the finest scale multi-spectral lighting dataset available for an entire city and explore how lighting metrics vary with built density and land-use. We found positive relationships between artificial lighting indicators and built density at coarse spatial scales, whilst at a local level lighting varied with land-use. Manufacturing and housing are the primary land-use zones responsible for the city’s brightly lit areas, yet manufacturing sites are relatively rare within the city. Our data suggests that efforts to address light pollution should broaden their focus from residential street lighting to include security lighting within manufacturing areas.

High-Resolution Imagery of Earth at Night: New Sources, Opportunities and Challenges

“…Color information from the ISS photographs could be used to approximately identify the mix of lighting types used in a region corresponding to a single pixel in the DNB stable lights product [10,29]. The DNB radiance could then be turned into an estimated spectral radiance for the pixel.…”

“…Recent papers have used aerial [9,10] and satellite [33] imagery to study light emitted towards space in detail. Kuechly et al [9] found that understanding the sources of light requires images with a resolution of at least 10 meters.…”

“…Images of the Earth at night are therefore an extremely useful tool for research involving human communities and their interaction with the environment. Night light data have been used in the past to study economic variables [1,2], socio-economic properties [3][4][5], population [6,7] and population density [8], built area [9,10], power consumption [11], greenhouse gas emissions [12], gas flaring [13], atmospheric chemistry [14], skyglow (light pollution) [15][16][17], the epidemiology of illness related to light exposure [18], among other analyses [19].…”

Benefits and costs of artificial nighttime lighting of the environment

“…The present global artificial nighttime lighting pattern is produced by the interaction between topography, the distributions of built structures and vegetation, and a complex mosaic of lighting systems, giving rise to spatially and temporally heterogeneous patterns of emissions, in terms of their intensity, spectra, and flicker (e.g., Cinzano et al 2001;Gaston et al 2012Gaston et al , 2013Hale et al 2013;Small and Elvidge 2013). The situation has become especially dynamic in recent years, with reductions in nighttime lighting being undertaken in some developed regions to lower energy costs, and expansions in lighting in other developed regions, as well as many developing ones.…”

Changes in outdoor lighting in Germany from 2012-2016

“…Nighttime observations of Earth at night have recently improved to allow observation of artificial lights at the scale of individual lamps via aerial photography [1,2], at the street level via astronaut photographs [3], and at neighborhood scale via satellite [4]. The near global coverage of the satellite data make it possible to assess some aspects of lighting on wide spatial scales.…”