scholarly journals Peri-Urban Growth into Natural Hazard-Prone Areas. Mapping Exposure Transformation of the Built Environment in Nairobi and Nyeri, Kenya from 1948 to Today

2021 ◽  
Author(s):  
Alexander Fekete
Keyword(s):  
Urban Growth ◽  
Urban Areas ◽  
Satellite Images ◽  
Natural Hazard ◽  
Flood Hazard ◽  
Disaster Risk ◽  
Aerial Images ◽  
Change Analysis ◽  
City Centres ◽  
Risk Practice

Abstract Kenya experiences massive urban growth, also into natural hazard-prone areas, exposing settlements and the natural environment to riverine and pluvial floods and other natural hazards. While Nairobi as the capital and principal city has been extensively analysed regarding urban growth and flood hazard in some central parts, awareness of growing peri-urban areas has not been studied as much. The results are of interest to other locations in Kenya and worldwide, too, since the current research and disaster risk practice focus is still too much on megacities and city centres. Therefore, the study compares urban growth into hazard areas in urban rims of Nairobi and Nyeri, Kenya. A change assessment from 1948 to 2020 is conducted by aerial images, declassified satellite images, and recent data. Urban growth rates are 10 to 20-fold, while growth into flood exposed areas ranges from 3 to 100-fold. This study reveals unused opportunities for expanding existing land-use change analysis back to the 1940s in data-scarce environments.

scholarly journals Urban Growth During Civilian and Military Administrations in Osogbo, Nigeria

2018 ◽  
Vol 50 (1) ◽  
pp. 1
Author(s):  
Olalekan John Taiwo
Keyword(s):  
Comparative Analysis ◽  
Urban Growth ◽  
Landscape Metrics ◽  
Urban Areas ◽  
Satellite Images ◽  
Morphological Characteristics ◽  
Temporal Patterns ◽  
Civilian Regimes ◽  
Landsat Satellite ◽  
The Military

Research on comparative analysis of urban growth and structure during military and civilian regimes most especially in Africa where coup d’etats is common and where private individuals mainly control land is limited. This study analyzed the temporal patterns and morphological characteristics of urban growth during the military and civilian regimes as well as during different civilian administrations using eight landscape metrics. Landsat satellite images of 1984, 1991, 2000, 2003, 2010 and 2014 were used in the analysis. It was found that urban growth occurred primarily through expansion (annexation) of extant urban areas rather than spontaneous and detached development.

scholarly journals Coupling scenarios of urban growth and flood hazard along the Emilia-Romagna coast (Italy)

2015 ◽  
Vol 3 (4) ◽  
pp. 2149-2189 ◽  
Author(s):  
I. Sekovski ◽  
C. Armaroli ◽  
L. Calabrese ◽  
F. Mancini ◽  
F. Stecchi ◽  
...  
Keyword(s):  
Urban Growth ◽  
Urban Areas ◽  
Flood Hazard ◽  
Digital Terrain Model ◽  
Terrain Model ◽  
Digital Terrain ◽  
Sleuth Model ◽  
Emilia Romagna Region ◽  
The Cost ◽  
Flood Prone Areas

Abstract. The extent of coastline urbanization reduces their resilience to flooding, especially in low lying areas. The study site is the Emilia-Romagna Region coastline (Italy), historically affected by marine storms and floods. The main aim of this study is to investigate the vulnerability of this coastal area to marine flooding by considering the dynamics of the forcing component (Total Water Level) and the dynamics of the receptor (urban areas). This was done by comparing the output of the three flooding scenarios (10, 100 and >100 year return periods) to the output of different scenarios of future urban growth up to 2050. Scenario-based marine flooding extents were derived by applying the Cost-Distance tool of ArcGIS® to a high resolution Digital Terrain Model. Three scenarios of urban growth (similar-as-historic, compact and sprawled) up to 2050 were estimated by applying the cellular automata based SLEUTH model. The results show that, if the urban growth is compact-like, flood-prone areas will largely increase with respect to similar-as-historic and sprawled growth scenarios. Combining the two methodologies can be useful for identify flood-prone areas that have a high potential for future urbanization, and is therefore crucial for coastal managers and planners.

scholarly journals GEOMETRIC OBJECT BASED BUILDING RECONSTRUCTION FROM SATELLITE IMAGERY DERIVED POINT CLOUDS

2019 ◽  
Vol XLII-2/W13 ◽  
pp. 73-78
Author(s):  
Z. Li ◽  
B. Xu ◽  
J. Shan
Keyword(s):  
Satellite Imagery ◽  
Urban Areas ◽  
Satellite Images ◽  
Point Clouds ◽  
Geometric Object ◽  
Aerial Images ◽  
Reconstruction Method ◽  
Object Based ◽  
High Resolution Satellite Images ◽  
Building Reconstruction

<p><strong>Abstract.</strong> 3D building models are needed for urban planning and smart city. These models can be generated from stereo aerial images, satellite images or LiDAR point clouds. In this paper, we propose a geometric object-based building reconstruction method from satellite imagery derived point clouds. The goal is to achieve a geometrically correct, topologically consistent, and non-redundant 3D representation for buildings in urban areas. The paper first introduces our motivation, followed by a comprehensive review on related works. We then introduce the methodology and process developed in this paper. Primary results from the point clouds generated from WorldView high resolution satellite images are used to demonstrate the performance of the approach.</p>

scholarly journals Urban Planning and Natural Hazard Governance

2019 ◽  
Author(s):  
Ricardo Marten ◽  
Theresa Abrassart ◽  
Camillo Boano
Keyword(s):  
Urban Planning ◽  
Urban Space ◽  
Urban Areas ◽  
Spatial Organization ◽  
Natural Hazard ◽  
Disaster Risk ◽  
Population Characteristics ◽  
Community Groups ◽  
Managing Risk ◽  
Inclusive Governance

The establishment of effective linkages between institutional urban planning and disaster risk strategies remains a challenge for formal governance structures. For governments at all administrative scales, disaster resilience planning has required systemic capacities that rely on structures of governance, humanitarian frameworks, and budgetary capacities. However, with growing urbanization trends, humanitarian responses and Disaster Risk Management (DRM) frameworks have had to adapt their operations in contexts with high population density, complex infrastructure systems, informal dynamics, and a broader range of actors. Urban areas concentrate an array of different groups with the capability of contributing to urban responses and strategies to cope with disaster effects, including community groups, government agencies, international organizations and humanitarian practitioners. In addition, cities have running planning structures that support their administration and spatial organization, with instruments that supply constant information about population characteristics, infrastructure capacity and potential weaknesses. Processes and data ascribed to urban planning can provide vital knowledge to natural hazard governance frameworks, from technical resources to conceptual approaches towards spatial analysis. Authorities managing risk could improve their strategic objectives if they could access and integrate urban planning information. Furthermore, a collaborative hazard governance can provide equity to multiple urban actors that are usually left out of institutional DRM, including nongovernmental organizations, academia, and community groups. Traditional top-down models can operate in parallel with horizontal arrangements, giving voice to groups with limited access to political platforms but who are knowledgeable on urban space and social codes. Their still limited recognition is evidence that there is still a disconnect between the intentions of global frameworks for inclusive governance, and the co-production of an urban planning designed for inclusive resilience.

scholarly journals Urban areas analysis using satellite image segmentation and deep neural network

2019 ◽  
Vol 135 ◽  
pp. 01064
Author(s):  
Vladimir Khryaschev ◽  
Leonid Ivanovsky
Keyword(s):  
Neural Networks ◽  
High Resolution ◽  
Convolutional Neural Networks ◽  
Urban Areas ◽  
High Performance ◽  
Satellite Images ◽  
Satellite Image ◽  
Aerial Images ◽  
Building Detection ◽  
High Resolution Satellite Images

The goal of our research was to develop methods based on convolutional neural networks for automatically extracting the locations of buildings from high-resolution aerial images. To analyze the quality of developed deep learning algorithms, there was used Sorensen-Dice coefficient of similarity which compares results of algorithms with real masks. These masks were generated automatically from json files and sliced on smaller parts together with respective aerial photos before the training of developed convolutional neural networks. This approach allows us to cope with the problem of segmentation for high-resolution satellite images. All in all we show how deep neural networks implemented and launched on modern GPUs of high-performance supercomputer NVIDIA DGX-1 can be used to efficiently learn and detect needed objects. The problem of building detection on satellite images can be put into practice for urban planning, building control of some municipal objects, search of the best locations for future outlets etc.

scholarly journals DENSE MULTI-VIEW IMAGE MATCHING FOR DSM GENERATION FROM SATELLITE IMAGES

2019 ◽  
Vol XLII-4/W18 ◽  
pp. 709-715
Author(s):  
A. Mahphood ◽  
H. Arefi ◽  
A. Hosseininaveh ◽  
A. A. Naeini
Keyword(s):  
Urban Areas ◽  
Point Cloud ◽  
Satellite Images ◽  
Tall Buildings ◽  
Aerial Images ◽  
Surface Model ◽  
Dense Point ◽  
Global Matching ◽  
High Resolution Images ◽  
View Matching

Abstract. Digital Surface Model (DSM) can be generated from stereo pairs of satellite or aerial images. Among the most state-of-the-art matching algorithms, Semi-Global Matching (SGM) has widely been used for generating DSM from both satellite and aerial images. This paper presents an approach to improve the accuracy of DSM generated by SGM from multi-view satellite images using a novel technique including several filters. The filters are used for deleting mismatches between very tall buildings in urban areas and removing the sea regions. The technique, in contrast to the recent multi-view matching approaches, considers some of the points generated with only a pair of images in the final DSM. The approach is implemented on five sequential high resolution images acquired by the Worldview-2 satellite. The results are locally evaluated in shape and quantitative terms in comparison with commercial software to reveal the capability of the approach to generate a reliable and dense point cloud. Experiments show that the proposed method can achieve below half-pixel accuracy.

scholarly journals Definição das áreas de perigo de inundação do rio Vacacaí no município de São Gabriel, RS

GeoTextos ◽  
2014 ◽  
Vol 10 (2) ◽  
Author(s):  
Vanessa Salvadé Silveira ◽  
Luis Eduardo De Souza Robaina ◽  
Romário Trentin
Keyword(s):  
Urban Area ◽  
Urban Areas ◽  
Satellite Images ◽  
Flood Hazard ◽  
Rio Grande ◽  
Flood Events ◽  
Analysis And Synthesis ◽  
Methodological Procedures ◽  
Definition Of ◽  
The City

A importância de estudos e mapeamentos relacionados às inundações é observada pelo expressivo aumento das pesquisas nas últimas décadas. O município de São Gabriel, no Estado do Rio Grande do Sul, possui mais de 80% de sua população na área urbana. Parte desta população se localiza no entorno do Rio Vacacaí e tem sido afetada seguidamente por inundações. Este estudo teve por objetivo o mapeamento das áreas com suscetibilidade e perigo de inundação na área urbana de São Gabriel. Os procedimentos metodológicos envolveram o levantamento e o processamento de imagens de satélite e dados topográficos que permitiram a análise e a síntese dos mapas e informações derivadas. A partir da análise de um recorte temporal de trinta anos verificou-se que em dezesseis anos há registros de inundações. No total destes dezesseis anos de eventos foram registrados trinta e dois casos em que a população foi afetada com inundações. A área total de suscetibilidade é 3,57 Km², representando 7,75% de toda a área urbana. As áreas de perigo cobrem 0,62 Km², representando 17,36% da suscetibilidade e 1,34% da área urbana do município. Este mapeamento representa uma importante ferramenta para subsidiar a prevenção e a redução de desastres naturais associados às inundações na área de estudo. Abstract DEFINITION OF FLOOD HAZARD AREAS VACACAÍ RIVER IN THE CITY OF SAN GABRIEL, RS The importance of studies related to flooding and mappings can be observed by the significant increase in research in recent decades. The municipality of São Gabriel, Rio Grande do Su State, has more than 80% of its population in urban areas. Part of this population is located in the nearness of Rio Vacacaí and has subsequently been affected by flood events. This study aims to map the areas with susceptibility and hazard of flooding in the urban area of São Gabriel. The methodological procedures involved the inventory of events, collection and processing of satellite images and topographic data. The analysis and synthesis of information derived from maps. From the analysis of the thirty years it was found that in sixteen years have records of flooding. A total of sixteen years of events were recorded thirty- -two where the population was affected with floods. The total susceptibility area is 3.57Km², representing 7.75% of the entire urban area. The danger areas are added to 0.62Km², representing 17.36% within the susceptibility and 1.34% compared to the urban area. This mapping is an important tool to help prevent and reduce natural disasters associated with floods in the study area.

scholarly journals The Impact of the Ring Roads on the Location Pattern of Shops in Town and City Centres. A Space Syntax Approach

2021 ◽  
Vol 13 (7) ◽  
pp. 3927
Author(s):  
Akkelies van Nes
Keyword(s):  
Urban Areas ◽  
Space Syntax ◽  
Optimal Location ◽  
Spatial Integration ◽  
Street Network ◽  
Location Pattern ◽  
Ring Road ◽  
Road Projects ◽  
The Impact ◽  
City Centres

This contribution demonstrates how inner ring roads change the location pattern of shops in urban areas with the application of the space syntax method. A market rational behaviour persists, in that shop owners always search for an optimal location to reach as many customers as possible. If the accessibility to this optimal location is affected by changes in a city’s road and street structure, it will affect the location pattern of shops. Initially, case studies of inner ring road projects in Birmingham, Coventry, Wolverhampton, Bristol, Tampere, and Mannheim show how their realisation affect the spatial structure of the street network of these cities and the location pattern of shops. The results of the spatial integration analyses of the street and road network are discussed with reference to changes in land-use before and after the implementation of ring roads, and current space syntax theories. As the results show, how an inner ring road is connected to and the type of the street network it is imposed upon dictates the resulting location pattern of shops. Shops locate and relocate themselves along the most spatially-integrated streets. Evidence on how new road projects influence the location pattern of shops in urban centres are useful for planning sustainable city centres.

scholarly journals Taking Implementation Seriously in the Evaluation of Urban Growth Management Strategies: “Safeguarding the Future” of the Antwerp City-Region

Land ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 159
Author(s):  
Clemens de Olde ◽  
Stijn Oosterlynck
Keyword(s):  
Urban Growth ◽  
Urban Areas ◽  
Growth Management ◽  
Management Strategies ◽  
Housing Prices ◽  
Policy Formulation ◽  
Land Values ◽  
Implementation Phase ◽  
The Future ◽  
Urban Growth Management

Contemporary evaluations of urban growth management (UGM) strategies often take the shape of quantitative measurements of land values and housing prices. In this paper, we argue that it is of key importance that these evaluations also analyse the policy formulation and implementation phases of growth management strategies. It is in these phases that the institutions and discourses are (trans)formed in which UGM strategies are embedded. This will enable us to better understand the conditions for growth management policies’ success or failure. We illustrate this point empirically with the case of demarcating urban areas in the region of Flanders, Belgium. Using the Policy Arrangement Approach, the institutional dynamics and discursive meanings in this growth instrument’s formulation and implementation phase are unravelled. More specifically, we explain how the Flemish strategic spatial planning vision of restraining sprawl was transformed into one of accommodating growth in the demarcation of the Antwerp Metropolitan Area, epitomised by two different meanings of the phrase “safeguarding the future.” In conclusion, we argue that, in Antwerp, the demarcation never solidified into a stable policy arrangement, rendering it largely ineffective. We end by formulating three recommendations to contribute to future attempts at managing urban growth in Flanders.

scholarly journals Accelerate disaster risk mapping using an automated zonal change detection model for loss estimation and recovery: a flood case study

2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Ali Amasha
Keyword(s):  
Change Detection ◽  
Satellite Images ◽  
Flash Flood ◽  
Disaster Risk ◽  
Loss Estimation ◽  
Risk Mapping ◽  
Detection Model ◽  
Applied Model ◽  
High Resolution Satellite Images ◽  
Before And After

Abstract Background The flash flood still constitutes one of the major natural meteorological disasters harmfully threatening local communities, that creates life losses and destroying infrastructures. The severity and magnitude of disasters always reflected from the size of impacts. Most of the conventional research models related to flooding vulnerability are focusing on hydro-meteorological and morphometric measurements. It, however, requires quick estimate of the flood losses and assess the severity using reliable information. An automated zonal change detection model applied, using two high-resolution satellite images dated 2009 and 2011 coupled with LU/LC GIS layer, on western El-Arish City, downstream of Wadi El-Arish basin. The model enabled to estimate the severity of a past flood incident in 2010. Results The model calculated the total changes based on the before and after satellite images based on pixel-by-pixel comparison. The estimated direct-damages nearly 32,951 m2 of the total mapped LU/LC classes; (e.g., 11,407 m2 as 3.17% of the cultivated lands; 6031 m2 as 7.22% of the built-up areas and 4040 m2 as 3.62% of the paved roads network). The estimated cost of losses, in 2010 economic prices for the selected three LU/LC classes, is nearly 25 million USD, for the cultivation fruits and olives trees, ~ 4 million USD for built-up areas and ~ 1 million USD for paved roads network. Conclusion The disasters’ damage and loss estimation process takes many detailed data, longtime, and costed as well. The applied model accelerates the disaster risk mapping that provides an informative support for loss estimation. Therefore, decision-makers and professionals need to apply this model for quick the disaster risks management and recovery.

Sign in / Sign up

Export Citation Format

Share Document