1,294 research outputs found

    It’s not big, it’s large: Mapping and characterizing urban landscapes of a different magnitude based on EO-data

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    The United Nation’s “World Urbanization Prospects” numeralise a migration process of a huge dimension – from rural to urban areas. While in 1975 only 37.7% of the world’s global population were urban dwellers, in 1990 already 43.0% and today little over 50% of all earth-dwellers are living in urban areas. For the year 2050 the expected number is even 67.2% (UN, 2011). This recent and prospective urbanization trend leads to new spatial dimensions of urban landscapes. One new trend is the spatial evolution of once polynuclei urban areas to so-called ‘mega-regions’. Because in literature clear definitions for the term ‘mega-region’ are missing or at least fuzzy and only qualitative we aim to derive quantitative physical spatial characteristics possibly defining mega-regions. For this purpose we use multi-temporal and multi-source satellite data to classify urbanized areas for an exemplary mega-region – the Hong Kong-Shenzhen-Guangzhou mega-region in Southern China – for the years 1975, 1990, 2000 and 2011. Furthermore, we suggest a set of spatial features potentially characteristic for the evolution of mega-regions. In particular we apply a multitude of spatial metrics at a defined spatial unit for the entire mega-region. The result is a novel spatial approach to capture, measure and analyze new dimensions and shapes of urban landscapes

    Spatiotemporal Evolution of Urban Agglomeration and Its Impact on Landscape Patterns in the Pearl River Delta, China

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    An urban agglomeration is the engine of regional and national economic growth, but also causes many ecological and environmental issues that emerge from massive land changes. In this study, the spatiotemporal evolution of an urban agglomeration was quantified and its impacts on the urban and regional landscape patterns were evaluated. It showed that the urbanized land area of the Pearl River Delta Urban Agglomeration (PRDUA) in China nearly quadrupled, having linearly increased from 1819.8 km2 to 7092.2 km2 between 1985 and 2015. The average annual growth rate presented a bimodal wave-like pattern through time, indicating that the PRDUA has witnessed two rounds of the urbanization process. The growth modes (e.g., leapfrog, edge-expansion, infilling) were detected and they exhibited co-existing but alternating dominating patterns during urbanization, demonstrating that the spatiotemporal evolution of the urban development of the PRDUA follows the “spiral diffusion-coalescence” hypothesis. The morphology of the PRDUA presented an alternating dispersal-compact pattern over time. The city-level and regional-level landscape patterns changed synchronously with the spatiotemporal evolution of the PRDUA over time. The urbanization of the PRDUA increased both the complexity and aggregation of the landscape, but also resulted in an increasing fragmentation and decreasing connectivity of the natural landscape in the Pearl River Delta region. These findings are helpful for better understanding how urban agglomerations evolve and in providing insights for regional urban planning and sustainable land management.Natural Science Foundation of ChinaNational Key R&D Program of ChinaChina Postdoctoral Science FoundationJoint-PhD project of Shanghai Jiao Tong University and The University of MelbournePeer Reviewe

    Evaluating Urban Expansion Using Integrated Remote Sensing and GIS technique: A Case Study in Greater Chengdu, China

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    The overall goal of this thesis is to better understand changes in the spatial pattern of urban growth and its impact on landscape configuration by conducting a case study in Greater Chengdu, an inland megacity in China. The objectives are as follows: 1) Quantifying changes in the spatial pattern of the study area between 2003 and 2013; 2) Evaluating the degree of urban sprawl over that period; 3) Evaluating urban expansion dynamics; and 4) Examining and defining the types of urban growth. Satellite imagery was employed to distinguish and identify different land surface categories. Integrated remote sensing and GIS (Geographic Information System) technique was used to analyse both qualitative and quantitative perspectives regarding the objectives. The results indicate that the urban area of Greater Chengdu doubled from 525.5 km2 to 1191.85 km2 during 2003 to 2013. The geographic footprint demonstrates that the distribution of the built-up area was dispersed and continues to grow more dispersed. The dominant type of urban growth is outward expansion, by which the city grew within a 10 km to 25 km radius surrounding the city center. A substantial infill phenomenon exists between a 5 km and 10 km radius from the city center. The urban core boundary expanded outward by 5 km, while the fringe of suburban area expanded outward by 10 km during the time period, which both indicate a substantial outward expansion over the city. The significant contribution of this study could benefit to many aspects such as comparative studies between cities or continuous studies relevant to urban growth

    Topology, homogeneity and scale factors for object detection: application of eCognition software for urban mapping using multispectral satellite image

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    The research scope of this paper is to apply spatial object based image analysis (OBIA) method for processing panchromatic multispectral image covering study area of Brussels for urban mapping. The aim is to map different land cover types and more specifically, built-up areas from the very high resolution (VHR) satellite image using OBIA approach. A case study covers urban landscapes in the eastern areas of the city of Brussels, Belgium. Technically, this research was performed in eCognition raster processing software demonstrating excellent results of image segmentation and classification. The tools embedded in eCognition enabled to perform image segmentation and objects classification processes in a semi-automated regime, which is useful for the city planning, spatial analysis and urban growth analysis. The combination of the OBIA method together with technical tools of the eCognition demonstrated applicability of this method for urban mapping in densely populated areas, e.g. in megapolis and capital cities. The methodology included multiresolution segmentation and classification of the created objects.Comment: 6 pages, 12 figures, INSO2015, Ed. by A. Girgvliani et al. Akaki Tsereteli State University, Kutaisi (Imereti), Georgi

    Exploration of eco-environment and urbanization changes in coastal zones: A case study in China over the past 20 years

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    Abstract With the rapid development of urbanization and population migration, since the 20th century, the natural and eco-environment of coastal areas have been under tremendous pressure due to the strong interference of human response. To objectively evaluate the coastal eco-environment condition and explore the impact from the urbanization process, this paper, by integrating daytime remote sensing and nighttime remote sensing, carried out a quantitative assessment of the coastal zone of China in 2000–2019 based on Remote Sensing Ecological Index (RSEI) and Comprehensive Nighttime Light Index (CNLI) respectively. The results showed that: 1) the overall eco-environmental conditions in China's coastal zone have shown a trend of improvement, but regional differences still exist; 2) during the study period, the urbanization process of cities continued to advance, especially in seaside cities and prefecture-level cities in Jiangsu and Shandong, which were much higher than the average growth rate; 3) the Coupling Coordination Degree (CCD) between the urbanization and eco-environment in coastal cities is constantly increasing, but the main contribution of environmental improvement comes from non-urbanized areas, and the eco-environment pressure in urbanized areas is still not optimistic. As a large-scale, long-term series of eco-environment and urbanization process change analysis, this study can provide theoretical support for mesoscale development planning, eco-environment condition monitoring and environmental protection policies from decision-makers

    中国における都市化総合評価及び環境への影響に関する研究

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    In Chapter one, research background and significance is investigated. In addition, previous studies and current situation in the research fields was reviewed and discussed. In Chapter two, an in-depth review of prior studies associated with the research topic was conducted. The literature review was carried out from three aspects: urbanization and eco-environment evalution and coordination, urban sprawl assessment and urban heat island investigation. In Chapter three, maximum entropy method was applied to help generate the evaluation system of eco-environment level and urbanization level at provincial scale. Comparison analysis and coordinate analysis was carried through to assess the development of urbanization and eco-environment as well as the balance and health degree of the city develops. In Chapter four, DMSP/OLS stable nighttime light dataset was used to measure and assess the urban dynamics from the extraction of built up area. Urban sprawl was evaluated by analyzing the landscape metrics which provided general understanding of the urban sprawl and distribution pattern characteristics could be got from the evaluation. In Chapter five, the investigation of surface urban heat island effects in Beijing city which derive from land surface temperature retrieval from remote sensing data of Landsat TM was carried out. In addition, spatial correlation and relationship between the urbanization level, vegetation coverage and surface urban heat island was carried out in this chapter. In Chapter six, all the works have been summarized and a conclusion of whole thesis is deduced.北九州市立大

    Un panorama de la télédétection de l'étalement urbain

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    The objective of this review paper is to provide an overview of remote sensing based research tackling urban sprawl issue. 113 articles were indexed and analyzed after research on bibliographical databases. These 113 articles are presented in the form of summary table giving highlights of the listed publications. Articles are divided into 6 categories (F, A, B, C, D, E) according to whether they are articles of methodology, characterization, prospective modeling-simulation, retrospective modeling-simulation, analysis of impacts or monitoring of urban sprawl. The summary table is conceived as a tool which can help researchers interested by the measurement and the analysis of urban sprawl.Cette note rend compte d'une recherche bibliographique dont l'objectif est de fournir un panorama des recherches utilisant la télédétection pour aborder la problématique de l'étalement urbain. 113 articles ont été répertoriés et analysés à la suite de recherches dans des bases de données bibliographiques. Ces 113 articles sont présentés sous forme de tableau récapitulatif donnant un aperçu général des publications recensées. Les articles sont répartis en 6 catégories (F, A, B, C, D, E) suivant qu'il s'agit d'articles de méthodologie, de caractérisation, de modélisation-simulation prospective, de modélisation-simulation rétrospective, d'analyse d'impacts ou de monitorage de l'étalement urbain. Le panorama est conçu comme un outil d'aide aux chercheurs qui s'intéressent à la mesure et à l'analyse de l'étalement urbain

    Land Cover classification and change-detection analysis using multi-temporal remote sensed imagery and landscape metrics

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    AbstractRemote Sensing (RS) data and techniques, in combination with GIS and landscape metrics, are fundamental to analyse and characterise Land Cover (LC) and its changes. The case study here described, has been conducted in the area of Avellino (Southern Italy). To characterise the dynamics of changes during a fifty year period (1954–2004), a multitemporal set of images has been processed: aerial photos (1954), and Landsat scenes (MSS 1975, TM 1985 and 1993, ETM+ 2004). LC pattern and its changes are linked to both natural and social processes whose driving role has been clearly demonstrated in the case study: after the disastrous Irpinia earthquake (1980), specific zoning laws and urban plans have significantly addressed landscape change

    Mapping regional land cover and land use change using MODIS time series

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    Coarse resolution satellite observations of the Earth provide critical data in support of land cover and land use monitoring at regional to global scales. This dissertation focuses on methodology and dataset development that exploit multi-temporal data from the Moderate Resolution Imaging Spectroradiometer (MODIS) to improve current information related to regional forest cover change and urban extent. In the first element of this dissertation, I develop a novel distance metric-based change detection method to map annual forest cover change at 500m spatial resolution. Evaluations based on a global network of test sites and two regional case studies in Brazil and the United States demonstrate the efficiency and effectiveness of this methodology, where estimated changes in forest cover are comparable to reference data derived from higher spatial resolution data sources. In the second element of this dissertation, I develop methods to estimate fractional urban cover for temperate and tropical regions of China at 250m spatial resolution by fusing MODIS data with nighttime lights using the Random Forest regression algorithm. Assessment of results for 9 cities in Eastern, Central, and Southern China show good agreement between the estimated urban percentages from MODIS and reference urban percentages derived from higher resolution Landsat data. In the final element of this dissertation, I assess the capability of a new nighttime lights dataset from the Visible Infrared Imaging Radiometer Suite (VIIRS) Day/Night Band (DNB) for urban mapping applications. This dataset provides higher spatial resolution and improved radiometric quality in nighttime lights observations relative to previous datasets. Analyses for a study area in the Yangtze River Delta in China show that this new source of data significantly improves representation of urban areas, and that fractional urban estimation based on DNB can be further improved by fusion with MODIS data. Overall, the research in this dissertation contributes new methods and understanding for remote sensing-based change detection methodologies. The results suggest that land cover change products from coarse spatial resolution sensors such as MODIS and VIIRS can benefit from regional optimization, and that urban extent mapping from nighttime lights should exploit complementary information from conventional visible and near infrared observations

    PENGARUH DINAMIKA LAHAN URBAN TERHADAP SEBARAN KEKRITISAN DAERAH RESAPAN PADA DAERAH ALIRAN SUNGAI YANG BERMUARA DI TELUK JAKARTA

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    Jakarta sebagai pusat pemerintahan dan perekonomian Indonesia, telah menjadi tujuan utama urbanisasi selama bertahun-tahun. Kondisi tersebut mendorong terjadinya perubahan tutupan lahan yang masif, terutama pertumbuhan lahan urban pada wilayah Jakarta dan peri urban Jakarta. Pertumbuhan lahan urban yang tidak terkendali memberikan dampak negatif bagi kota Jakarta, mengingat secara geografis kota Jakarta merupakan wilayah hilir dari delapan Daerah Aliran Sungai (DAS). Penelitian ini memiliki lima tujuan, yang pertama menganalisis tren pertumbuhan lahan urban pada seluruh DAS yang bermuara di Teluk Jakarta. Tahap analisis ini dilakukan dengan melihat tipe pertumbuhan lahan urban (infilling, edge expansion dan outlying), pola pertumbuhan lahan urban melalui analisis spasial metrik dan arah pertumbuhan lahan urban melalui pembagian delapan zona sesuai arah mata angin. Hasilnya menunjukkan bahwa tipe pertumbuhan lahan urban pada areal studi didominasi tipe Edge Expansion. Pola pertumbuhan lahan urban cenderung semakin kompak dengan tingkat sprawl yang cenderung menurun. Selain itu pertumbuhan lahan urban di wilayah Barat Laut (NW) cenderung lebih teratur dibanding wilayah lain, sedangkan wilayah Timur (E) cenderung sebaliknya. Tujuan kedua adalah menganalisis faktor pendorong dan penghambat pertumbuhan lahan urban melalui studi referensi dan wawancara mendalam. Hasilnya diperoleh tiga belas faktor pendorong dan enam faktor penghambat pertumbuhan lahan urban. Lahan urban eksisting menjadi faktor pendorong utama pertumbuhan lahan urban pada areal studi. Tujuan ketiga adalah memprediksi pertumbuhan lahan urban tahun 2029 dengan model cellular automata melalui dua skenario yaitu skenario tren pertumbuhan lahan urban (skenario 1) dan skenario rencana pengembanan wilayah (skenario 2). Hasilnya, prediksi pertumbuhan lahan urban tahun 2029 untuk skenario 1 dan skenario 2 tidak menunjukkan perbedaan yang signifikan. DAS Bekasi, DAS Angke Pesanggrahan dan DAS Cisadane diprediksi menjadi DAS dengan pertumbuhan lahan urban terbesar tahun 2029. Tujuan keempat adalah menganalisis kekritisan daerah resapan mengacu pada Penyusunan Rencana Teknik Rehabilitasi Hutan dan Lahan Daerah Aliran Sungai. Hasilnya menunjukkan bahwa pertumbuhan lahan urban tahun 2001 - 2017 maupun tahun 2017 - prediksi tahun 2029 (skenario 1 dan 2) telah menambah secara signifikan luas daerah resapan dengan tingkatan agak kritis dan kritis. Tujuan yang kelima adalah menyusun strategi pengendalian pertumbuhan lahan urban pada areal studi melalui analisis SWOT. Hasil analisis merekomendasikan upaya pengendalian pertumbuhan lahan urban dengan strategi konservatif. Srategi yang dapat diterapkan berupa pembuatan sistem informasi berbasis internet (komputer) yang mampu menjadi jembatan koordinasi sekaligus media pengawasan serta penguatan peran BKSP Jabodetabekpunjur dalam pengendalian pertumbuhan lahan urban. Kata Kunci : Dinamika Lahan Urban, Kekritisan Daerah Resapan, Daerah Aliran Sungai, cellular automata, Teluk Jakarta, analisis SWOT Jakarta as the center of Indonesia's economy and govenment, has become the main destination for urbanization for many years. This condition encourages massive land cover changes, especially urban growth in Jakarta and peri-urban areas of Jakarta. Uncontrolled urban growth has negative impacts on Jakarta, considering that geographically Jakarta is a downstream area of eight watersheds. This study has five objectives, the first to analyze urban growth trends in all watersheds that flow into the Jakarta Bay. This analysis is carried out through studies of urban growth types (infilling, edge expansion and outlying), urban growth patterns through spatial metric analysis and urban growth direction by dividing the study area into eight zones. The results show that the type of urban growth in the study area is dominated by the Edge Expansion type. Urban growth patterns tend to be more compact with sprawl rates that tend to decline. In addition, urban growth in the Northwest region (NW) tends to be more regular than other regions, while the Eastern region (E) tends to be the opposite. The second objective is to analyze the driving factors and inhibiting factors of urban growth through reference studies and in-depth interviews. The results obtained thirteen driving factors and six inhibiting factors of urban growth. Existing urban areas were the main driving factor for urban growth in the study area. The third objective is to predict urban growth in 2029 with cellular automata models through two scenarios, namely scenario of urban growth trends (scenario 1) and scenario of regional development plans (scenario 2). The result show that predictions of urban growth in 2029 for scenario 1 and scenario 2 did not show a significant difference. The Bekasi watershed, Angke Pesanggrahan watershed and the Cisadane watershed are predicted to experience the largest urban growth in 2029. The fourth objective is to analyze the criticality level of the catchment area referring to Planning Procedures for Forest and Land Rehabilitation Engineering Watershed. The results show that urban growth from 2001 to 2017 and 2017 to the prediction of 2029 have significantly increased catchment areas with rather critical and critical levels. The fifth objective is to develop a strategy for controlling urban growth in the study area through a SWOT analysis. The results of the analysis recommend controlling the urban growth with a conservative strategy. The strategy that can be applied is the creation of an internet-based information system (computer) that is able to become a bridge of coordination as well as a media of supervision. In addition, it is necessary to strengthen the role of the BKSP Jabodetabekpunjur in controlling urban growth. Keywords: Urban dynamics, criticality level of the cactment area, watershed, cellular automata, Jakarta Bay, SWOT analysi
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