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Urban Land-System Synergies and Governance Using Remote Sensing, Modeling and Big Data, Analysis

A special issue of Remote Sensing (ISSN 2072-4292). This special issue belongs to the section "Urban Remote Sensing".

Deadline for manuscript submissions: closed (15 December 2021) | Viewed by 56508

Special Issue Editors


E-Mail Website
Guest Editor
Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
Interests: urban land-system dynamic and ecological remote sensing
Special Issues, Collections and Topics in MDPI journals

E-Mail Website
Guest Editor
1. Research Center for Ecology and Environment of Central Asia, Chinese Academy of Sciences, Urumqi 830011, China
2. State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China
3. Shandong Provincial Key Laboratory of Water and Soil Conservation and Environmental Protection, College of Resources and Environment, Linyi University, Linyi 270600, China
Interests: carbon cycle; urban ecosystem; temperate desert; climate change; land-use change; machine learning; ecological modelling

E-Mail Website
Guest Editor
1. Department of Geography, Ghent University, 9000 Ghent, Belgium
2. University of Chinese Academy of Sciences, Beijing 100039, China
3. Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China
4. Institute of Geographic Sciences and natural resources, Chinese Academy of Sciences, Beijing, China
5. Royal Meteorological Institute, Brussels, Belgium
Interests: remote sensing and ecological process in cities
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

The significance of urban land-system synergies and spatial governance are increasingly emerging toward sustainable target and livable environment in cities. Satellite remote sensing, process-based models and big data are playing the pivotal roles for obtaining spatially explicit knowledge for better planning or managing city. This session expects to provide an opportunity for urban land-system synergies and governance with remote sensing, modeling and big data integration. Remote sensing, modeling and big data technologies as well as the improvement of mapping algorithms, such as impervious surface area, surface radiation and heat fluxes, heat island, and surface runoff associated with urbanization will be expected to share and exchange in this session. In addition, optimized schemes on urban-land system, i.e. low impact development in cities, carbon emission reduction in cities and so on, is suitable for this session.

The fourth Open Science Meeting of the Global Land Programme (GLP 4th OSM 2019) will be held from the 24-26 of April 2019 in Bern, Switzerland. In this conference, we will organize a session on above theme, which will attribute to the conference theme “How do we support transformation? New frontiers in studying and governing land systems”. As a follow-up to the workshop, we are calling for papers on the work presented at the session of GLP 4th OSM 2019. In addition to this, we welcome papers from the global research community actively involved in this session. As such, the special issue is open to anyone doing research in this field. The selection of papers for publication will depend on quality and rigor of research. The potential topics may include the followings:

  1. Data integration or fusion methods from remote sensing, process-based modeling, or big data
  2. High-spatial resolution mapping of urban land cover/land use (i.e., impervious surface, green space)
  3. Spatial mapping and exploratory analysis on urban heat island, urban hydrological process, and other ecological factors.
  4. Knowledge mining or discovery from available fine-scale spatially explicit information for urban governance

Prof. Dr. Dengsheng Lu
Dr. Wenhui Kuang
Prof. Dr. Chi Zhang
Dr. Tao Pan
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Remote Sensing is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Urban-land system synergies
  • Urban eco-regulation
  • Urban remote sensing
  • Urban ecological process modeling
  • Geo-big data mining
  • Urban land/cover change
  • Urban impervious surface mapping
  • Urban heat island mitigation
  • Low impact development in cities
  • Urban green infrastructure
  • Hot spots for urban governance
  • Urban climate adaption
  • Carbon emission reduction in cities
  • Sustainable cities planning
  • Optimized urban-land system design

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Further information on MDPI's Special Issue policies can be found here.

Published Papers (11 papers)

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Research

21 pages, 7219 KiB  
Article
Synergies between Urban Heat Island and Urban Heat Wave Effects in 9 Global Mega-Regions from 2003 to 2020
by Chunzhu Wei, Wei Chen, Yang Lu, Thomas Blaschke, Jian Peng and Desheng Xue
Remote Sens. 2022, 14(1), 70; https://doi.org/10.3390/rs14010070 - 24 Dec 2021
Cited by 23 | Viewed by 5300
Abstract
Global urbanization significantly impacts the thermal environment in urban areas, yet urban heat island (UHI) and urban heat wave (UHW) studies at the mega-region scale have been rare, and the impact study of urbanization is still lacking. In this study, the MODIS land [...] Read more.
Global urbanization significantly impacts the thermal environment in urban areas, yet urban heat island (UHI) and urban heat wave (UHW) studies at the mega-region scale have been rare, and the impact study of urbanization is still lacking. In this study, the MODIS land surface temperature (LST) product was used to depict the UHI and UHW in nine mega-regions globally between 2003 and 2020. The absolute and percentile-based UHW thresholds were adopted for both daily and three-day windows to analyze heat wave frequency, and UHW magnitude as well as frequency were compared with UHI variability. Results showed that a 10% increase in urban built-up density led to a 0.20 °C to 0.95 °C increase in LST, a 0.59% to 7.17% increase in hot day frequency, as well as a 0.08% to 0.95% increase in heat wave number. Meanwhile, a 1 °C increase in UHI intensity (the LST differences between the built-up and Non-built-up areas) led to a 2.04% to 92.15% increase in hot day frequency, where daytime LST exceeds 35 °C and nighttime LST exceeds 25 °C, as well as a 3.30% to 33.67% increase in heat wave number, which is defined as at least three consecutive days when daily maximum temperature exceeds the climatological threshold. In addition, the increasing rates of UHW magnitudes were much faster than the expansion rates of built-up areas. In the mega-regions of Boston, Tokyo, São Paulo, and Mexico City in particular, the increasing rates of UHW hotspot magnitudes were over 2 times larger than those of built-up areas. This indicated that the high temperature extremes, represented by the increase in UHW frequency and magnitudes, were concurrent with an increase in UHI under the context of climate change. This study may be beneficial for future research of the underlying physical mechanisms on urban heat environment at the mega-region scale. Full article
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Graphical abstract

Graphical abstract
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<p>The 9 mega-regions selected and their built-up (BU) areas from 2000 to 2018.</p>
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<p>Schematic of the percolation-based clustering method; (x1,y1) and (x2,y2) define the percola tion threshold at which the giant component emerges.</p>
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<p>Time series of mean LST, CHT, HWN90th and HWN97.5th in the summer daytime from 2003 to 2020 in the 9 mega-regions in the built-up and Non-built-up areas. Error bars are graphical representations of the standard deviation of four indicators in the mega-region (B = Built-up area, N = Non-built-up area).</p>
Full article ">Figure 4
<p>Daytime of Mean LST, CHT, HWN90th, and HWN97.5th within each UDI level during the study period. Each class is plotted from 18 data points which represent the areal mean LST of the class in different mega-regions from 2003–2020, respectively.</p>
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<p>Spatial distribution of mean LST, CHN, and HWN over the study period in the 9 mega-regions.</p>
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<p>Spatial distribution of percolation-based hotspots in the 9 mega-regions in three time periods.</p>
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<p>Time series of mean LST, CHT, and HWN in the 9 mega-regions.</p>
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15 pages, 5030 KiB  
Article
Identifying Urban Functional Areas in China’s Changchun City from Sentinel-2 Images and Social Sensing Data
by Shouzhi Chang, Zongming Wang, Dehua Mao, Fusheng Liu, Lina Lai and Hao Yu
Remote Sens. 2021, 13(22), 4512; https://doi.org/10.3390/rs13224512 - 10 Nov 2021
Cited by 12 | Viewed by 3508
Abstract
The urban functional area is critical to an understanding of the complex urban system, resource allocation, and management. However, due to urban surveys’ focus on geographic objects and the mixture of urban space, it is difficult to obtain such information. The function of [...] Read more.
The urban functional area is critical to an understanding of the complex urban system, resource allocation, and management. However, due to urban surveys’ focus on geographic objects and the mixture of urban space, it is difficult to obtain such information. The function of a place is determined by the activities that take place there. This study employed mobile phone signaling data to extract temporal features of human activities through discrete Fourier transform (DFT). Combined with the features extracted from the point of interest (POI) data and Sentinel images, the urban functional areas of Changchun City were identified using a random forest (RF) model. The results indicate that integrating features derived from remote sensing and social sensing data can effectively improve the identification accuracy and that features derived from dynamic mobile phone signaling have a higher identification accuracy than those derived from POI data. The human activity characteristics on weekends are more distinguishable for different functional areas than those on weekdays. The identified urban functional layout of Changchun is consistent with the actual situation. The residential functional area has the highest proportion, accounting for 33.51%, and is mainly distributed in the central area, while the industrial functional area and green-space are distributed around. Full article
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Graphical abstract
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<p>Location of the central area of Changchun. The data source of the remote sensing image base map is Sentinel-2A.</p>
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<p>Spatial distribution characteristics of POI. (<b>a</b>) Location of different types of POI; (<b>b</b>) Density of POI.</p>
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<p>Spatial pattern of cell towers. (<b>a</b>) Location of cell towers; (<b>b</b>) Density of cell towers.</p>
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<p>The overall process of integrating remote sensing data and social sensing data to identify urban functional areas.</p>
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<p>Profiles of mobile phone time series in different functional areas.</p>
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<p>Comparison of the classification accuracy using different feature combinations.</p>
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<p>‘F1_macro’ values under different parameter combinations.</p>
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<p>Comparison of feature importance. (<b>a</b>) The top 20 important features; (<b>b</b>) Importance ranking of mobile phone signaling-derived features.</p>
Full article ">Figure 8 Cont.
<p>Comparison of feature importance. (<b>a</b>) The top 20 important features; (<b>b</b>) Importance ranking of mobile phone signaling-derived features.</p>
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<p>Spatial pattern of urban functional areas.</p>
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23 pages, 36272 KiB  
Article
Identifying Surface Urban Heat Island Drivers and Their Spatial Heterogeneity in China’s 281 Cities: An Empirical Study Based on Multiscale Geographically Weighted Regression
by Lu Niu, Zhengfeng Zhang, Zhong Peng, Yingzi Liang, Meng Liu, Yazhen Jiang, Jing Wei and Ronglin Tang
Remote Sens. 2021, 13(21), 4428; https://doi.org/10.3390/rs13214428 - 3 Nov 2021
Cited by 43 | Viewed by 4342
Abstract
The spatially heterogeneous nature and geographical scale of surface urban heat island (SUHI) driving mechanisms remain largely unknown, as most previous studies have focused solely on their global performance and impact strength. This paper analyzes diurnal and nocturnal SUHIs in China based on [...] Read more.
The spatially heterogeneous nature and geographical scale of surface urban heat island (SUHI) driving mechanisms remain largely unknown, as most previous studies have focused solely on their global performance and impact strength. This paper analyzes diurnal and nocturnal SUHIs in China based on the multiscale geographically weighted regression (MGWR) model for 2005, 2010, 2015, and 2018. Compared to results obtained using the ordinary least square (OLS) model, the MGWR model has a lower corrected Akaike information criterion value and significantly improves the model’s coefficient of determination (OLS: 0.087–0.666, MGWR: 0.616–0.894). The normalized difference vegetation index (NDVI) and nighttime light (NTL) are the most critical drivers of daytime and nighttime SUHIs, respectively. In terms of model bandwidth, population and ?fine particulate matter are typically global variables, while ?NDVI, intercept (i.e., spatial context), and NTL are local variables. The nighttime coefficient of ?NDVI is significantly negative in the more economically developed southern coastal region, while it is significantly positive in northwestern China. Our study not only improves the understanding of the complex drivers of SUHIs from a multiscale perspective but also provides a basis for urban heat island mitigation by more precisely identifying the heterogeneity of drivers. Full article
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Figure 1

Figure 1
<p>Geolocation of the selected 281 cities and six regions (Northwest, North, Northeast, East, South, and Southwest) of China in this study. The background information is annual precipitation across China.</p>
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<p>Spatial distributions of the variables used in the present study (using 2015 as an example). Note: SUHI = surface urban heat island intensity; ΔNDVI = urban−rural differences of NDVI; ΔPM<sub>2.5</sub> = urban−rural differences of fine particulate matter; ΔPre = urban−rural differences of precipitation; NTL = urban nighttime light; Pop = the population at the end of the year.</p>
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<p>The overall framework of the study. Note: SUHI = surface urban heat island intensity; NDVI = normalized difference vegetation index; MODIS LST = Moderate Resolution Imaging Spectroradiometer land surface temperature; ESA CCI = European Space Agency’s Climate Change Initiative; SRTM DEM = Shuttle Radar Topography Mission Digital Elevation Model; MGWR = the population at the end of the year.</p>
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<p>Spatial distributions of MGWR’s local R<sup>2</sup> in 2005, 2010, 2015, and 2018.</p>
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<p>Spatial distributions of MGWR’s local R<sup>2</sup> in 2005, 2010, 2015, and 2018.</p>
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<p>Spatial distributions of the coefficients of ΔNDVI, ΔPrecipitation, and Intercept for the daytime MGWR model in 2005, 2010, 2015, and 2018.</p>
Full article ">Figure 5 Cont.
<p>Spatial distributions of the coefficients of ΔNDVI, ΔPrecipitation, and Intercept for the daytime MGWR model in 2005, 2010, 2015, and 2018.</p>
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<p>Spatial distributions of the coefficients of ΔNDVI, ΔPrecipitation, Intercept for the nighttime MGWR model in 2005, 2010, 2015, and 2018.</p>
Full article ">Figure 6 Cont.
<p>Spatial distributions of the coefficients of ΔNDVI, ΔPrecipitation, Intercept for the nighttime MGWR model in 2005, 2010, 2015, and 2018.</p>
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<p>Spatial distributions of the coefficients of NTL, ΔPM<sub>2.5</sub>, and Population for the daytime MGWR model in in 2005, 2010, 2015, and 2018.</p>
Full article ">Figure 7 Cont.
<p>Spatial distributions of the coefficients of NTL, ΔPM<sub>2.5</sub>, and Population for the daytime MGWR model in in 2005, 2010, 2015, and 2018.</p>
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<p>Spatial distributions of the coefficients of NTL, ΔPM<sub>2.5</sub>, and Population for the nighttime MGWR model in 2005, 2010, 2015, and 2018.</p>
Full article ">Figure 8 Cont.
<p>Spatial distributions of the coefficients of NTL, ΔPM<sub>2.5</sub>, and Population for the nighttime MGWR model in 2005, 2010, 2015, and 2018.</p>
Full article ">Figure 9
<p>Spatial distributions of the coefficients of ΔNDVI for the daytime MGWR model in the summer and winter of 2005, 2010, 2015, and 2018.</p>
Full article ">Figure 9 Cont.
<p>Spatial distributions of the coefficients of ΔNDVI for the daytime MGWR model in the summer and winter of 2005, 2010, 2015, and 2018.</p>
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<p>Spatial distributions of the coefficients of ΔNDVI for the nighttime MGWR model in the summer and winter of 2005, 2010, 2015, and 2018.</p>
Full article ">Figure 10 Cont.
<p>Spatial distributions of the coefficients of ΔNDVI for the nighttime MGWR model in the summer and winter of 2005, 2010, 2015, and 2018.</p>
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21 pages, 5597 KiB  
Article
Evaluating the Dynamic Changes of Urban Land and Its Fractional Covers in Africa from 2000–2020 Using Time Series of Remotely Sensed Images on the Big Data Platform
by Zherui Yin, Wenhui Kuang, Yuhai Bao, Yinyin Dou, Wenfeng Chi, Friday Uchenna Ochege and Tao Pan
Remote Sens. 2021, 13(21), 4288; https://doi.org/10.3390/rs13214288 - 25 Oct 2021
Cited by 6 | Viewed by 2879
Abstract
Dramatic urban land expansion and its internal sub-fraction change during 2000–2020 have taken place in Africa; however, the investigation of their spatial heterogeneity and dynamic change monitoring at the continental scale are rarely reported. Taking the whole of Africa as a study area, [...] Read more.
Dramatic urban land expansion and its internal sub-fraction change during 2000–2020 have taken place in Africa; however, the investigation of their spatial heterogeneity and dynamic change monitoring at the continental scale are rarely reported. Taking the whole of Africa as a study area, the synergic approach of normalized settlement density index and random forest was applied to assess urban land and its sub-land fractions (i.e., impervious surface area and vegetation space) in Africa, through time series of remotely sensed images on a cloud computing platform. The generated 30-m resolution urban land/sub-land products displayed good accuracy, with comprehensive accuracy of over 90%. During 2000–2020, the evaluated urban land throughout Africa increased from 1.93 × 104 km2 to 4.18 × 104 km2, with a total expansion rate of 116.49%, and the expanded urban area of the top six countries accounted for more than half of the total increments, meaning that the urban expansion was concentrated in several major countries. A turning green Africa was observed, with a continuously increasing ratio of vegetation space to built-up area and a faster increment of vegetation space than impervious surface area (i.e., 134.43% vs., 108.88%) within urban regions. A better living environment was also found in different urbanized regions, as the newly expanded urban area was characterized by lower impervious surface area fraction and higher vegetation fraction compared with the original urban area. Similarly, the humid/semi-humid regions also displayed a better living environment than arid/semi-arid regions. The relationship between socioeconomic development factors (i.e., gross domestic product and urban population) and impervious surface area was investigated and both passed the significance test (p < 0.05), with a higher fit value in the former than the latter. Overall, urban land and its fractional land cover change in Africa during 2000–2020 promoted the well-being of human settlements, indicating the positive effect on environments. Full article
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Figure 1

Figure 1
<p>Geographic information map of Africa. Notes: the yellow and green in the upper right corner of the location diagram represent climatic regions of Africa. The main map represents elevation and administrative divisions of Africa.</p>
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<p>Examples of the verified points for the fractional land covers within urban regions throughout Africa in 2020. Note: the density levels from 1 to 10 represent the fractions of impervious surface area or vegetation space at 10% intervals from 0.01% to 100%, separately. The buffer region represents an outward buffer distance radius of 100 km from the edge of each city.</p>
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<p>Spatial distribution and statistical map of urban expansion in Africa during 2000–2020. (<b>a</b>) Urban land distribution in 2020 (dark yellow) in sub-Africa regions of Middle Africa, Eastern Africa, Southern Africa, Northern Africa, and Western Africa; and the urban land statistics at the national scale in years 2000, 2010, and 2020, respectively. (<b>b</b>) The sample cities of urban expansion in Cairo ((<b>b1</b>), Egypt), Abuja ((<b>b2</b>), Nigeria), and Bangui ((<b>b3</b>), Central Africa). (<b>c</b>) Total urban expansion changes at the national scale from 2000 to 2020, and we only marked the number when a total urban expansion area was more than 1000 km<sup>2</sup> in each country throughout the studied period.</p>
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<p>Spatial statistics of the fractional urban land structure in Africa during 2000–2020. (<b>a</b>–<b>c</b>) Show the average density of the fractional intra-urban impervious surface area (UISA), the fractional intra-urban vegetation space (UVS), and the fractional intra-urban other land-cover (UOL) at the country scale in 2000, 2010, and 2020, respectively, and the size of the circle represents the total area of urban land on a national scale. (<b>d</b>) Statistics of the changes in average density of the fractional UISA, UVS, and UOL in sub-African regions of Middle Africa, Eastern Africa, Southern Africa, Northern Africa, and Western Africa in 2000, 2010, and 2020, respectively.</p>
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<p>Regional examples of impervious surface area fractions and vegetation space fractions in Tanzania (i.e., the first line) and Egypt (i.e., the second line) of Africa. In each line, we provide 2-m Google images, 30-m Landsat images, 30-m fractional impervious surface area, and vegetation space, respectively. Notes: the regional example in the first line is located in humid/semi-humid areas and the regional example in the second line is located in arid/semi-arid areas.</p>
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<p>Statistics of the functional relationship values between the urban impervious surface area and gross domestic product, and between urban impervious surface area and urban population in Africa during 2000–2020. Notes: “Δ” represents the words “dynamic change”, ISA: impervious surface area, GDP: gross domestic product.</p>
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16 pages, 6208 KiB  
Article
Mapping Global Urban Impervious Surface and Green Space Fractions Using Google Earth Engine
by Wenhui Kuang, Yali Hou, Yinyin Dou, Dengsheng Lu and Shiqi Yang
Remote Sens. 2021, 13(20), 4187; https://doi.org/10.3390/rs13204187 - 19 Oct 2021
Cited by 18 | Viewed by 5975
Abstract
Urban impervious surfaces area (ISA) and green space (GS), two primary components of urban environment, are pivotal in detecting urban environmental quality and addressing global environmental change issues. However, the current global mapping of ISA and GS is not effective enough to accurately [...] Read more.
Urban impervious surfaces area (ISA) and green space (GS), two primary components of urban environment, are pivotal in detecting urban environmental quality and addressing global environmental change issues. However, the current global mapping of ISA and GS is not effective enough to accurately delineate in urban areas due to the mosaicked and complex structure. To address the issue, the hierarchical architecture principle and subpixel metric method were applied to map 30 m global urban ISA and GS fractions for the years 2015 and circa 2020. We use random forest algorithms for retrieval of the Normalized Settlement Density Index and Normalized Green Space Index from Landsat images using Google Earth Engine. The correlation coefficients of global urban ISA and GS fractions were all higher than 0.9 for 2015 and circa 2020. Our results show global urban ISA and GS areas in circa 2020 were 31.19 × 104 km2 and 17.16 × 104 km2, respectively. The novel ISA and GS fractions product can show potential applications in assessing the effects of urbanization on climate, ecology, and urban sustainability. Full article
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Graphical abstract
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<p>The hierarchical scale principle and subpixel metric method for mapping ISA and GS fractions.</p>
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<p>The strategy for mapping urban impervious surface area (ISA) and green space (GS) products (NSDI, Normalized Settlement Density Index; NGSI, Normalized Green Space Index).</p>
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<p>(<b>a</b>) shows the selection principle of the spatial distribution of sample points; (<b>b1</b>,<b>b2</b>) show the sampling areas in a Google Earth image; whereas (<b>b3</b>,<b>b4</b>) show the digitized proportions of the impervious (pink) and vegetation (green) areas.</p>
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<p>(<b>a</b>) shows the distribution of global urban ecoregions and sampled cities; (<b>b1</b>,<b>b2</b>) show the impervious surface area fraction in sampled cities; (<b>c1</b>,<b>c2</b>) show the urban and non-urban land in sampled cities; (<b>b3</b>,<b>b4</b>,<b>c3</b>,<b>c4</b>) show the digitized the impervious and vegetation areas.</p>
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<p>Examples of spatial distribution of NSDI and NGSI in selected regions circa 2020. (<b>a1</b>,<b>b1</b>,<b>c1</b>,<b>d1</b>,<b>e1</b>) show the NSDI in selected regions; (<b>a2</b>,<b>b2</b>,<b>c2</b>,<b>d2</b>,<b>e2</b>) show the NGSI in selected regions.</p>
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<p>Examples of urban impervious surface area fraction in selected cities. (<b>a1</b>,<b>b1</b>,<b>c1</b>,<b>d1</b>,<b>e1</b>) show the urban impervious surface area fraction in 2005; (<b>a2</b>,<b>b2</b>,<b>c2</b>,<b>d2</b>,<b>e2</b>) show the urban impervious surface area fraction circa 2020.</p>
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<p>Spatial distribution of global ISA (<b>a1</b>) and GS (<b>a2</b>) circa 2020. (<b>b1</b>,<b>c1</b>,<b>d</b><b>1</b>,<b>e1</b>,<b>f1</b>,<b>g</b><b>1</b>) show the areas of ISA in different regions; (<b>b2</b>,<b>c2</b>,<b>d2</b>,<b>e2</b>,<b>f2</b>,<b>g2</b>) show the areas of GS in different regions.</p>
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<p>The percentages of impervious surface areas and green spaces in urban land areas in selected cities.</p>
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<p>Comparisons between our dataset and other existing datasets. (GUE, global urban expansion [<a href="#B21-remotesensing-13-04187" class="html-bibr">21</a>]; GUL, global urban land [<a href="#B25-remotesensing-13-04187" class="html-bibr">25</a>]; GHSL, global human settlement layer [<a href="#B23-remotesensing-13-04187" class="html-bibr">23</a>]; GAIA, global artificial impervious area [<a href="#B9-remotesensing-13-04187" class="html-bibr">9</a>]; and MSMT, global ISA [<a href="#B27-remotesensing-13-04187" class="html-bibr">27</a>]).</p>
Full article ">
24 pages, 8503 KiB  
Article
Assessing Community-Level Livability Using Combined Remote Sensing and Internet-Based Big Geospatial Data
by Likai Zhu, Yuanyuan Guo, Chi Zhang, Jijun Meng, Lei Ju, Yuansuo Zhang and Wenxue Tang
Remote Sens. 2020, 12(24), 4026; https://doi.org/10.3390/rs12244026 - 9 Dec 2020
Cited by 26 | Viewed by 4344
Abstract
With rapid urbanization, retrieving livability information of human settlements in time is essential for urban planning and governance. However, livability assessments are often limited by data availability and data update cycle, and this problem is more serious when making an assessment at finer [...] Read more.
With rapid urbanization, retrieving livability information of human settlements in time is essential for urban planning and governance. However, livability assessments are often limited by data availability and data update cycle, and this problem is more serious when making an assessment at finer spatial scales (e.g., community level). Here we aim to develop a reliable and dynamic model for community-level livability assessment taking Linyi city in Shandong Province, China as a case study. First, we constructed a hierarchical index system for livability assessment, and derived data for each index and community from remotely sensed data or Internet-based geospatial data. Next, we calculated the livability scores for all communities and assessed their uncertainties using Monte Carlo simulations. The results showed that the mean livability score of all communities was 59. The old urban and newly developed districts of our study area had the best livability, and got a livability score of 62 and 58 respectively, while industrial districts had the poorest conditions with an average livability score of 48. Results by dimension showed that the old urban district had better conditions of living amenity and travel convenience, but poorer conditions of environmental health and comfort. The newly developed districts were the opposite. We conclude that our model is effective and extendible for rapidly assessing community-level livability, which provides detailed and useful information of human settlements for sustainable urban planning and governance. Full article
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Graphical abstract

Graphical abstract
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<p>Geographical features of the study area. The inset maps show the geographic location of Linyi (<b>a</b>) in China and (<b>b</b>) in Shandong Province. (<b>c</b>) The main map demonstrates the spatial distribution of communities and urban functional zones. Unlike countries such as the United States and Canada, the community in China often takes the form of a gated residential area with a clear boundary, and consists of several blocks of buildings.</p>
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<p>Procedures to develop the livability assessment model. The four steps are shown in the boxes with the bold frame.</p>
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<p>Comparison of the walking distance to the nearest park from Baidu Map API and Gaode Map API.</p>
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<p>The density and fitted probability distribution of all AHP-derived weights based on a questionnaire survey by index. (<b>a</b>–<b>p</b>) represent different indices at the bottom level as shown in <a href="#remotesensing-12-04026-t001" class="html-table">Table 1</a>.</p>
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<p>The distribution of livability scores for one community derived from Monte Carlo simulations for 10,000 times.</p>
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<p>Single–index assessment of livability based on the 16 indices under 4 dimensions, as shown in <a href="#remotesensing-12-04026-t001" class="html-table">Table 1</a>. (<b>a</b>,<b>b</b>) spatial patterns of index values within the dimension of environmental health; (<b>c</b>–<b>g</b>) spatial patterns of index value within the dimension of environmental comfort; (<b>h</b>–<b>l</b>) spatial patterns of index values within the dimension of living amenity; (<b>m</b>–<b>p</b>) spatial patterns of index values within the dimension of travel convenience.</p>
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<p>Livability assessment by dimension. (<b>a</b>) Environmental health; (<b>b</b>) Environmental comfort; (<b>c</b>) Living amenity; (<b>d</b>) Travel convenience. The communities of the first class were the ones whose scores were above 90th percentile, the second-class communities were the ones whose scores were within the range of the 81st and the 90th percentile, the third-class communities were the ones whose scores were within the range of the 61st and the 80th percentile, the fourth-class communities were the ones whose scores were within the range of the 41st and the 60th percentile, and the fifth-class communities were the ones whose scores were below the 40th percentile.</p>
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<p>Average scores of different livability dimensions summarized by urban functional types and overall livability scores summarized by urban functional types.</p>
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<p>Spatial patterns of livability scores and its uncertainty for all communities. (<b>a</b>) The 5th percentile of livability scores from Monte Carlo simulations. (<b>b</b>) The 95th percentile of livability scores from Monte Carlo simulations. (<b>c</b>) The standard deviation of livability scores from Monte Carlo simulations. (<b>d</b>) Five livability ranks classified using the quantile method. The communities of the first class were the ones whose scores were above 90th percentile, the second-class communities were the ones whose scores were within the range from 81th to 90th percentile, the third-class communities were the ones whose scores were within the range from 61th to 80th percentile, the fourth-class communities were the ones whose scores were within the range from 41th to 60th percentile, and the fifth-class communities were the ones whose scores were below 40th percentile.</p>
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<p>Spatial pattern of clusters of high and low livability scores. Clusters indicate that a high (low) livability score is surrounded primarily by high (low) values.</p>
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<p>Spatial pattern of average real-estate transaction prices of communities in 2019.</p>
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<p>Relationship between housing prices and livability scores. Housing prices show a significantly positive correlation with livability scores (<span class="html-italic">p</span> &lt; 0.05).</p>
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19 pages, 8184 KiB  
Article
Recording Urban Land Dynamic and Its Effects during 2000–2019 at 15-m Resolution by Cloud Computing with Landsat Series
by Yulin Dong, Zhibin Ren, Yao Fu, Zhenghong Miao, Ran Yang, Yuanhe Sun and Xingyuan He
Remote Sens. 2020, 12(15), 2451; https://doi.org/10.3390/rs12152451 - 30 Jul 2020
Cited by 43 | Viewed by 4718
Abstract
Cities, the core of the global climate change and economic development, are high impact land cover land use change (LCLUC) hotspots. Comprehensive records of land cover land use dynamics in urban regions are essential for strategic climate change adaption and mitigation and sustainable [...] Read more.
Cities, the core of the global climate change and economic development, are high impact land cover land use change (LCLUC) hotspots. Comprehensive records of land cover land use dynamics in urban regions are essential for strategic climate change adaption and mitigation and sustainable urban development. This study aims to develop a Google Earth Engine (GEE) application for high-resolution (15-m) urban LCLUC mapping with a novel classification scheme using pan-sharpened Landsat images. With this approach, we quantified the annual LCLUC in Changchun, China, from 2000 to 2019, and detected the abrupt changes (turning points of LCLUC). Ancillary data on social-economic status were used to provide insights on potential drivers of LCLUC by examining their correlation with change rate. We also examined the impacts of LCLUC on environment, specifically air pollution. Using this approach, we can classify annual LCLUC in Changchun with high accuracy (all above 0.91). The change detection based on the high-resolution wall-to-wall maps show intensive urban expansion with the compromise of cropland from 2000 to 2019. We also found the growth of green space in urban regions as the result of green space development and management in recent years. The changing rate of different land types were the largest in the early years of the observation period. Turning points of land types were primarily observed in 2009 and 2010. Further analysis showed that economic and industry development and population migration collectively drove the urban expansion in Changchun. Increasing built-up areas could slow wind velocity and air exchange, and ultimately led to the accumulation of PM2.5. Our implement of pan-sharpened Landsat images facilitates the wall-to-wall mapping of temporal land dynamics at high spatial resolution. The primary use of GEE for mapping urban land makes it replicable and transferable by other users. This approach is a first crucial step towards understanding the drivers of change and supporting better decision-making for sustainable urban development and climate change mitigation. Full article
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<p>Location of Changchun city defined by the outermost highway ring. The WRS-2 path/row shows three Landsat scenes that occupy the study area.</p>
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<p>Correlation of the original band values and their pan-sharpened counterparts. This study pan-sharpened Landsat images by a 5 × 5 pixel-window that reserves the spectral information and enhances the spatial heterogeneity of pixels.</p>
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<p>Integrated processing of automatic thresholding and multilevel decision rule. DOY: day of year.</p>
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<p>NDVI fluctuations show the phenological difference between green space and cropland in Changchun. (<b>a</b>) Fitted NDVI indicates the earlier growth of green space. (<b>b</b>) Land surface temperature dynamics indicate crops start to ripen after DOY 208 due to an accumulation of daytime temperature of more than 1900 Celsius. (<b>c</b>) Derivative of fitted NDVI. SOS: start of season; SOP: start of peak; EOP: end of peak, EOS: end of season. See [<a href="#B42-remotesensing-12-02451" class="html-bibr">42</a>] for remotely sensed urban phenology.</p>
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<p>Annual distribution and areal extent of land cover land use in Changchun from 2000 to 2019. Raster maps of the year 2000, 2005, 2010, 2015, and 2019 are zoomed in for a demo purpose.</p>
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<p>Statistical relationships between land dynamics, socio-economic records, and environmental fluctuation. Panels (<b>a</b>–<b>e</b>) are normalized changes in observing variables. Note that the single star (*) and double star (**) indicate statistical significance at 0.05 and 0.01, respectively. BR: built-up ratio; GBR: green space/built-up ratio; GR: green ratio; CR: cropland ratio; UP: urban population; GDP: gross domestic product; AS: GDP of agriculture sector; IS: GDP of industry sector; SS: GDP of service sector; NPP: net primary production; ATEM: average temperature; AWV: average wind velocity; PM<sub>2.5</sub>: fine particles.</p>
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<p>Inter-comparison of the original Landsat 8 image and its pan-sharpened counterparts by different methods. Panels (<b>a</b>–<b>c</b>) are examples of different locations. The HSV algorithm is a built-in method in GEE [<a href="#B29-remotesensing-12-02451" class="html-bibr">29</a>]. The Landsat ID indicates that the compared image is a TOA image of the OLI sensor derived from 25 September 2017, and its path/row is 118/29.</p>
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<p>Test results show the availability of this study method in mapping urban land cover land use for temperate cities. For a demo purpose, only cities with a population of more than 5 million have considered. OA: overall accuracy. See <a href="#remotesensing-12-02451-f0A3" class="html-fig">Figure A3</a> for the distribution of validation samples.</p>
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<p>The total number of Landsat images from 2000 to 2019 indicates a less clean observation for Bangkok than that for Beijing. (<b>a</b>) Within the areal extent of 8.4 km × 8.3 km in Beijing and 10.4 km × 10.4 km in Bangkok, respectively, the total image number of Landsat 7 and Landsat 8 from 2000 to 2019. (<b>b</b>) Number ratio of images filtered by cloud cover. Panels (<b>c</b>,<b>d</b>) are the phenology of Beijing and Bangkok, respectively.</p>
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<p>Distribution of samples applied for accuracy assessment.</p>
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<p>Maps showing the annual change rate of three major land cover types from 2000 to 2019. For demonstration purposes, the spatial statistical process was conducted in a pixel of 1.5 km × 1.5 km because the original pixel length is 15-m. ACR: annual change rate.</p>
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<p>Distribution of validation samples used for assessing the accuracy of big city maps. These samples were collected by stratified sampling from Google Earth. See <a href="#remotesensing-12-02451-f008" class="html-fig">Figure 8</a> for the maps.</p>
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13 pages, 10845 KiB  
Article
Investigating the Patterns and Dynamics of Urban Green Space in China’s 70 Major Cities Using Satellite Remote Sensing
by Wenhui Kuang and Yinyin Dou
Remote Sens. 2020, 12(12), 1929; https://doi.org/10.3390/rs12121929 - 15 Jun 2020
Cited by 51 | Viewed by 6422
Abstract
Urban green space (UGS) plays a pivotal role in improving urban ecosystem services and building a livable environment for urban dwellers. However, remotely sensed investigation of UGS at city scale is facing a challenge due to the pixels’ mosaics of buildings, squares, roads [...] Read more.
Urban green space (UGS) plays a pivotal role in improving urban ecosystem services and building a livable environment for urban dwellers. However, remotely sensed investigation of UGS at city scale is facing a challenge due to the pixels’ mosaics of buildings, squares, roads and green spaces in cities. Here we developed a new algorithm to unmix the fraction of UGS derived from Landsat TM/ETM/8 OLI using a big-data platform. The spatiotemporal patterns and dynamics of UGSs were examined for 70 major cities in China between 2000 and 2018. The results showed that the total area of UGS in these cities grew from 2780.66 km2 in 2000 to 6764.75 km2 in 2018, which more than doubled its area. As a result, the UGS area per inhabitant rose from 15.01 m2 in 2000 to 18.09 m2 in 2018. However, an uneven layout of UGS occurred among the coastal, western, northeastern and central zones. For example, the UGS percentage in newly expanded urban areas in the coastal zone rose significantly in 2000–2018, with an increase of 2.51%, compared to the decline in UGS in cities in the western zone. Therefore, the effective strategies we have developed should be adopted to show disparities and promote green infrastructure capacity building in those cities with less green space, especially in western China. Full article
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<p>Flow chart of data processing and analysis.</p>
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<p>Accuracy assessment of urban green space (UGS) fractions.</p>
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<p>Changes in urban green space area of China’s 70 cities during 2000–2018.</p>
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<p>Urban green space and park distributions in typical cities from different zones: (<b>a</b>) Shenzhen in the coastal zone; (<b>b</b>) Changchun in the northeastern zone; (<b>c</b>) Wuhan in the central zone; (<b>d</b>) Chengdu in the western zone.</p>
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<p>The urban green space (UGS) area changes between the built-up areas in 2000 and newly expanded areas in 2000–2018 in 70 cities.</p>
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<p>Landsat Images of typical cities and major parks.</p>
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<p>The distribution of urban parks in cities in China.</p>
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18 pages, 3726 KiB  
Article
Comparison of Changes in Urban Land Use/Cover and Efficiency of Megaregions in China from 1980 to 2015
by Shu Zhang, Chuanglin Fang, Wenhui Kuang and Fengyun Sun
Remote Sens. 2019, 11(15), 1834; https://doi.org/10.3390/rs11151834 - 6 Aug 2019
Cited by 20 | Viewed by 4019
Abstract
Urban land use/cover and efficiency are important indicators of the degree of urbanization. However, research about comparing their changes at the megaregion level is relatively rare. In this study, we depicted the differences and inequalities of urban land and efficiency among megaregions in [...] Read more.
Urban land use/cover and efficiency are important indicators of the degree of urbanization. However, research about comparing their changes at the megaregion level is relatively rare. In this study, we depicted the differences and inequalities of urban land and efficiency among megaregions in China using China’s Land Use/cover Dataset (CLUD) and China’s Urban Land Use/cover Dataset (CLUD-Urban). Furthermore, we analyzed regional inequality using the Theil index. The results indicated that the Guangdong-Hong Kong-Macao Great Bay Area had the highest proportion of urban land (8.03%), while the Chengdu-Chongqing Megaregion had the highest proportion of developed land (64.70%). The proportion of urban impervious surface area was highest in the Guangdong-Hong Kong-Macao Great Bay Area (75.16%) and lowest in the Chengdu-Chongqing Megaregion (67.19%). Furthermore, the highest urban expansion occurred in the Yangtze River Delta (260.52 km2/a), and the fastest period was 2000–2010 (298.19 km2/a). The decreasing Theil index values for the urban population and economic density were 0.305 and 1.748, respectively, in 1980–2015. This study depicted the development trajectory of different megaregions, and will expect to provide a valuable insight and new knowledge on reasonable urban growth modes and sustainable goals in urban planning and management. Full article
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<p>Study area and the location of the megaregions.</p>
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<p>Flow chart on analysis of artificial construction intensity and urban land efficiency.</p>
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<p>Urban expansion in the five megaregions.</p>
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<p>The urban impervious density from CLUD-Urban for cities in 2015.</p>
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<p>Regional divergence of the urban land expansion.</p>
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<p>Changes in Theil index in different megaregions.</p>
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20 pages, 14351 KiB  
Article
Using Nighttime Light Data and POI Big Data to Detect the Urban Centers of Hangzhou
by Ge Lou, Qiuxiao Chen, Kang He, Yue Zhou and Zhou Shi
Remote Sens. 2019, 11(15), 1821; https://doi.org/10.3390/rs11151821 - 4 Aug 2019
Cited by 53 | Viewed by 7478
Abstract
The worldwide development of multi-center structures in large cities is a prevailing development trend. In recent years, China’s large cities developed from a predominantly mono-centric to a multi-center urban space structure. However, the definition and identification city centers is complex. Both nighttime light [...] Read more.
The worldwide development of multi-center structures in large cities is a prevailing development trend. In recent years, China’s large cities developed from a predominantly mono-centric to a multi-center urban space structure. However, the definition and identification city centers is complex. Both nighttime light data and point of interest (POI) data are important data sources for urban spatial structure research, but there are few integrated applications for these two kinds of data. In this study, visible infrared imaging radiometer suite (NPP-VIIRS) nighttime imagery and POI data were combined to identify the city centers in Hangzhou, China. First, the optimal parameters of multi-resolution segmentation were determined by experiments. The POI density was then calculated with the segmentation results as the statistical unit. High–high clustering units were then defined as the main centers by calculating the Anselin Local Moran’s I, and a geographically weighted regression model was used to identify the subcenters according to the square root of the POI density and the distances between the units and the city center. Finally, a comparison experiment was conducted between the proposed method and the relative cut-off_threshold method, and the experiment results were compared with the evaluation report of the master plan. The results showed that the optimal segmentation parameters combination was 0.1 shape and 0.5 compactness factors. Two main city centers and ten subcenters were detected. Comparison with the evaluation report of the master plan indicated that the combination of nighttime light data and POI data could identify the urban centers accurately. Combined with the characteristics of the two kinds of data, the spatial structure of the city could be characterized properly. This study provided a new perspective for the study of the spatial structure of polycentric cities. Full article
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<p>Location of the study area. The inset map shows the location of Hangzhou in Zhejiang province.</p>
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<p>Point of interest (POI) data of Hangzhou in May 2018: (<b>a</b>) Spatial distribution of POI, each point stands for one point of interest. (<b>b</b>) Gridded map of POI number with 500 m resolution, representing the number of POI in a square of 25 ha.</p>
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<p>Workflow of the proposed method. NTL: nighttime light; NPP-VIIRS: visible infrared imaging radiometer suite.</p>
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<p>NPP-VIIRS nighttime light intensity map of Hangzhou in May 2018. (NPP-VIIRS: Suomi-NPP satellite, visible infrared imaging radiometer).</p>
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<p>of segments changes with segmentation scale factor using multi-resolution segmentation in eCognition.</p>
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<p>Segmentation results of nine groups of shape factor and compactness factor combinations (here shows a small region). The yellow lines show the boundaries of segments. The image with red frame means the factor combination we chose to use (shape factor is 0.1 and compactness factor is 0.5).</p>
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<p>Weighted mean variances of segments for different scale factors (3,4,5,6,7,8).</p>
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<p>Density of POI counted in segmentation units. The small images on the right show detailed views of the areas of small units and big units respectively.</p>
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<p>Four cluster types of the results of local spatial autocorrelation analysis for the POI densities in units.</p>
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<p>Main centers and subcenters detected by the proposed method. The main centers are shown in <b>red,</b> and the subcenters are shown in <b>yellow</b>. The river and lake layer contains West Lake and the Qiantang River.</p>
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<p>Centers detected by different methods and datasets. All centers detected by threshold are shown in orange. In the results from the Local Moran’s I (LMI) and geographically weighted regression (GWR) methods, the main centers are shown in <b>red</b>, and the subcenters are shown in <b>yellow</b>.</p>
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<p>Hot spot analysis result of population data.</p>
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<p>Centers areas intersect results. The overlapped center areas were shown in <b>green</b> and the different center areas were shown in <b>gray</b>.</p>
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<p>Centers proposed in the master plan and detected by our experiment.</p>
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22 pages, 25756 KiB  
Article
City-Level Comparison of Urban Land-Cover Configurations from 2000–2015 across 65 Countries within the Global Belt and Road
by Tao Pan, Wenhui Kuang, Rafiq Hamdi, Chi Zhang, Shu Zhang, Zhili Li and Xin Chen
Remote Sens. 2019, 11(13), 1515; https://doi.org/10.3390/rs11131515 - 27 Jun 2019
Cited by 23 | Viewed by 5169
Abstract
The configuration of urban land-covers is essential for improving dwellers’ environments and ecosystem services. A city-level comparison of land-cover changes along the Belt and Road is still unavailable due to the lack of intra-urban land products. A synergistic classification methodology of sub-pixel un-mixing, [...] Read more.
The configuration of urban land-covers is essential for improving dwellers’ environments and ecosystem services. A city-level comparison of land-cover changes along the Belt and Road is still unavailable due to the lack of intra-urban land products. A synergistic classification methodology of sub-pixel un-mixing, multiple indices, decision tree classifier, unsupervised (SMDU) classification was established in the study to examine urban land covers across 65 capital cities along the Belt and Road during 2000–2015. The overall accuracies of the 15 m resolution urban products (i.e., the impervious surface area, vegetation, bare soil, and water bodies) derived from Landsat Enhanced Thematic Mapper Plus (ETM+)/Operational Land Imager (OLI) images were 92.88% and 93.19%, with kappa coefficients of 0.84 and 0.85 in 2000 and 2015, respectively. The built-up areas of 65 capital cities increased from 23,696.25 km2 to 29,257.51 km2, with an average growth rate of 370.75 km2/y during 2000–2015. Moreover, urban impervious surface area (ISA) expanded with an average rate of 401.92 km2/y, while the total area of urban green space (UGS) decreased with an average rate of 17.59 km2/y. In different regions, UGS changes declined by 7.37% in humid cities but increased by 14.61% in arid cities. According to the landscape ecology indicators, urban land-cover configurations became more integrated (?Shannon’s Diversity Index (SHDI) = −0.063; ?Patch Density (PD) = 0.054) and presented better connectivity (?Connectance Index (CON) = +0.594). The proposed method in this study improved the separation between ISA and bare soil in mixed pixels, and the 15 m intra-urban land-cover product provided essential details of complex urban landscapes and urban ecological needs compared with contemporary global products. These findings provide valuable information for urban planners dealing with human comfort and ecosystem service needs in urban areas. Full article
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<p>Location of the “Global Belt and Road” and associated geographical information.</p>
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<p>Technological process of the sub-pixel un-mixing, multiple indices, decision tree classifier, unsupervised classification (SMDU) methodology. Abbreviations: MNF, minimum noise fraction; V-I-S, vegetation-impervious surface-soil; FCLS: fully constrained least-squares solution model; LSDI, low-albedo soil difference index; VS, vegetation space; NDVI, normalized difference vegetation index; MNDWI: modified normalized difference water index.</p>
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<p>Urban spatial expansion in each city for the years 2000 and 2015 along the Belt and Road. Notes: The height of the column represents the area of the built-up region in each city.</p>
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<p>The top 10 cities with the most rapid urban land expansion during 2000–2015 along the Belt and Road, including the current built-up areas (km<sup>2</sup>) and built-up area changes (km<sup>2</sup>). Abbreviations: BEI, Beijing, China; BAN, Bangkok, Thailand; KUA, Kuala Lumpur, Malaysia; JAK, Jakarta, Indonesia; NEW, New_Deli, India; ABU, Abu Dhabi, United Arab Emirates; ANK, Ankara, Turkey; DHA, Dhaka, Bangladesh; DOH, Doha, Qatar; COL, Colombo, Sri Lanka.</p>
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<p>Intra-urban land-cover changes in 2000 (<b>a</b>) and 2015 (<b>b</b>) within the Global Belt and Road. Abbreviations: ISA, impervious surface area; UGS: urban green space; UBS: urban bare soil; UWB: urban water body. The circle size represents the built-up area in each capital city.</p>
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<p>Examples of final classified intra-urban land-cover images. Notes: The description of the selected cities are as follows in the <a href="#remotesensing-11-01515-f006" class="html-fig">Figure 6</a>. Kuala Lumpur, Malaysia, East Asia, coastal city, humid region; Dhaka, Bangladesh, South Asia, inland city, humid region; Astana, Kazakhstan; Central Asia, inland city with adequate surface water resources, arid region; Tehran, Iran, Middle East, inland city, arid region; Dushanbe, Tajikistan, and Bishkek, Kyrgyzstan, Central Asia, inland city, arid region.</p>
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<p>Urban landscape index features between 2000 and 2015 in the central zones. (<b>a</b>) Spatial distribution of the central zones within the Global Belt and Road; (<b>b</b>) for the landscape scale indicator, the values of PD, LPI, LSI, CON, and SHDI; (<b>c</b>) for the class scale indicator: the values of PD; (<b>d</b>) for the class scale indicator: the values of LPI; (<b>e</b>) for the class scale indicator: the values of CON; and (<b>f</b>) for the class scale indicator: the values of LSI. Abbreviations: PD: patch density; LPI: largest patch index; LSI, landscape shape index; CON: connectance index; SHDI: Shannon’s diversity index.</p>
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<p>Comparison of the urban land-cover classification results (i.e., urban land 15 m product in the epoch of 2000) obtained by this methodology and results from contemporary global products (i.e., global land-cover 30 m in the epoch of 2000, GLC 30 m; global human settlement layer 38 m in the epoch of 2000, GHSL 38 m; European space agency global land-cover data 300 m in the epoch of 2000, ESA-GlobCover 300 m; and moderate-resolution imaging spectroradiometer 500 m in the epoch of 2001, MODIS 500 m).</p>
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