scholarly journals InSAR Multitemporal Data over Persistent Scatterers to Detect Floodwater in Urban Areas: A Case Study in Beletweyne, Somalia

2020 ◽  
Vol 13 (1) ◽  
pp. 37
Author(s):  
Luca Pulvirenti ◽  
Marco Chini ◽  
Nazzareno Pierdicca
Keyword(s):  
Urban Area ◽  
Urban Areas ◽  
The Other ◽  
Spatial Average ◽  
Calibration Data ◽  
Suburban Areas ◽  
Persistent Scatterers ◽  
Optical Images ◽  
Interferometric Phase ◽  
Multitemporal Data

A stack of Sentinel-1 InSAR data in an urban area where flood events recurrently occur, namely Beletweyne town in Somalia, has been analyzed. From this analysis, a novel method to deal with the problem of flood mapping in urban areas has been derived. The approach assumes the availability of a map of persistent scatterers (PSs) inside the urban settlement and is based on the analysis of the temporal trend of the InSAR coherence and the spatial average of the exponential of the InSAR phase in each PS. Both interferometric products are expected to have high and stable values in the PSs; therefore, anomalous decreases may indicate that floodwater is present in an urban area. The stack of Sentinel-1 data has been divided into two subsets. The first one has been used as a calibration set to identify the PSs and determine, for each PS, reference values of the coherence and the spatial average of the exponential of the interferometric phase under standard non-flooded conditions. The other subset has been used for validation purposes. Flood maps produced by UNOSAT, analyzing very-high-resolution optical images of the floods that occurred in Beletweyne in April–May 2018, October–November 2019, and April–May 2020, have been used as reference data. In particular, the map of the April–May 2018 flood has been used for training purposes together with the subset of Sentinel-1 calibration data, whilst the other two maps have been used to validate the products generated by applying the proposed method. The main product is a binary map of flooded PSs that complements the floodwater map of rural/suburban areas produced by applying a well-consolidated algorithm based on intensity data. In addition, a flood severity map that labels the different districts of Beletweyne, as not, partially, or totally flooded has been generated to consolidate the validation. The results have confirmed the effectiveness of the proposed method.

Land Use, Urban Design, and Nonwork Travel: Reproducing Other Urban Areas’ Empirical Test Results in Portland, Oregon

2000 ◽  
Vol 1722 (1) ◽  
pp. 27-37 ◽  
Author(s):  
Marlon G. Boarnet ◽  
Michael J. Greenwald
Keyword(s):  
Land Use ◽  
Urban Area ◽  
Urban Design ◽  
Urban Areas ◽  
Empirical Test ◽  
The Other ◽  
Test Results ◽  
Trip Generation ◽  
New Urbanist ◽  
New Variables

Research on nonwork automobile trip generation and land use previously conducted by researchers is replicated for the Portland, Oregon, region. Additionally, new variables examining new urbanist arguments are incorporated. The results suggest that any links between land use and nonwork trip behavior act primarily by influencing trip costs, in terms of distances traveled and speeds achieved, rather than directly influencing the number of trips made. This analysis is consistent with the other research, suggesting that this model is not sensitive to errors that might arise due to the unique characteristics of the urban area under review.

scholarly journals An Urban Flooding Index for Unsupervised Inundated Urban Area Detection Using Sentinel-1 Polarimetric SAR Images

2021 ◽  
Vol 13 (22) ◽  
pp. 4511
Author(s):  
Hui Zhang ◽  
Zhixin Qi ◽  
Xia Li ◽  
Yimin Chen ◽  
Xianwei Wang ◽  
...  
Keyword(s):  
Urban Area ◽  
Urban Areas ◽  
Ground Truth ◽  
Detection Accuracy ◽  
Urban Flooding ◽  
Polarimetric Sar ◽  
Sar Images ◽  
Ground Truth Data ◽  
Optical Images ◽  
Coefficient Increase

Urban flooding causes a variation in radar return from urban areas. However, such variation has not been thoroughly examined for different polarizations because of the lack of polarimetric SAR (PolSAR) images and ground truth data simultaneously collected over flooded urban areas. This condition hinders not only the understanding of the effect mechanism of urban flooding under different polarizations but also the development of advanced methods that could improve the accuracy of inundated urban area detection. Using Sentinel-1 PolSAR and Jilin-1 high-resolution optical images acquired on the same day over flooded urban areas in Golestan, Iran, this study investigated the characteristics and mechanisms of the radar return changes induced by urban flooding under different polarizations and proposed a new method for unsupervised inundated urban area detection. This study found that urban flooding caused a backscattering coefficient increase (BCI) and interferometric coherence decrease (ICD) in VV and VH polarizations. Furthermore, VV polarization was more sensitive to the BCI and ICD than VH polarization. In light of these findings, the ratio between the BCI and ICD was defined as an urban flooding index (UFI), and the UFI in VV polarization was used for the unsupervised detection of flooded urban areas. The overall accuracy, detection accuracy, and false alarm rate attained by the UFI-based method were 96.93%, 91.09%, and 0.95%, respectively. Compared with the conventional unsupervised method based on the ICD and that based on the fusion of backscattering coefficients and interferometric coherences (FBI), the UFI-based method achieved higher overall accuracy. The performance of VV was evaluated and compared to that of VH in the flooded urban area detection using the UFI-, ICD-, and FBI-based methods, respectively. VV polarization produced higher overall accuracy than VH polarization in all the methods, especially in the UFI-based method. By using VV instead of VH polarization, the UFI-based method improved the detection accuracy by 38.16%. These results indicated that the UFI-based method improved flooded urban area detection by synergizing the BCI and ICD in VV polarization.

scholarly journals MANAJEMEN LIMPASAN AIR HUJAN DI DAERAH PERKOTAAN DENGAN RAIN GARDEN DAN MENJAGANYA DARI KEBERADAAN NYAMUK

2017 ◽  
Vol 3 (2) ◽  
Author(s):  
Nova Annisa ◽  
Hafiizh Prasetia
Keyword(s):  
Sustainable Development ◽  
Life Cycle ◽  
Urban Area ◽  
Urban Areas ◽  
Descriptive Analysis ◽  
Good Treatment ◽  
The Other ◽  
Rain Garden ◽  
Runoff Water ◽  
Concrete Layer

ABSTRAKRain garden adalah salah satu praktik pembangunan berkelanjutan untuk mengatasi masalah limpasan air hujan. Rain garden sangat cocok sekali dikembangkan di daerah perkotaan dimana lahan resapan sudah mulai hilang digantikan dengan lapisan beton yang kaku. Tujuan dari kajian ini adalah mengungkapkan bagaimana model rain garden untuk daerah perkotaan dan bagaimana cara untuk menjaganya dari keberadaan nyamuk. Kajian dilakukan dengan analisis deskriptif. Berdasarkan hasil pengamatan diketahui bahwa model rain garden dapat dikembangkan untuk daerah perkotaan. Model rain garden yang satu dan yang lainnya dapat dihubungkan dengan pipa atau gorong-gorong sehingga memungkinkan rain garden berjalan optimal. Rain garden yang bagus harus tidak ada genangan lebih dari 72 jam. Hal ini bertujuan untuk menjaga dari keberadaan nyamuk yang dianggap mengganggu. Perawatan yang bagus terhadap rain garden juga mampu untuk menjaganya dari nyamuk. Kata Kunci: rain garden, nyamuk, siklus hidup  ABSTRACT Rain garden is one of sustainable development practices to overcome the problem of runoff water. Rain garden is very well suited to develop in urban areas where the recharge ground has begun to disappear replaced with a rigid concrete layer. The purpose of this study is to reveal how the rain garden model for urban areas and how to guard against the presence of mosquitoes. The study was conducted by descriptive analysis. Based on the observation, it is known that rain garden model can be developed for urban area. Rain garden models that one and the other can be connected with a pipe or culvert that allows rain garden to run optimally. A nice rain garden should have no puddle over 72 hours. It aims to keep from the presence of mosquitoes that are considered disturbing. Good treatment of rain garden is also able to keep it from mosquitoes. Keywords: rain garden, mosquitoes, life cycle

Cultivated Lands within Urban Area

2013 ◽  
pp. 143-157
Author(s):  
G. Mauro
Keyword(s):  
Urban Area ◽  
Urban Areas ◽  
Suburban Areas ◽  
North East ◽  
The North ◽  
Relevant Role ◽  
Agricultural Areas ◽  
The City ◽  
The Town

Several studies put in evidence the relevant role of cultivated lands in the urban areas. Using GIS methodologies in order to map agricultural areas near or within the town, it is possible to analyze their relationship with the urban area. In this study, the author used several different cartography sources, like digital cartography and orthophotos, in order to locate the urban domestic gardens and the terraced landscapes accurately. The study area is a medium city of a North-East Region of Italy, Trieste. Built on a hill morphology, it had a great and fast growth in the 19th and 20th centuries. These changes deeply transformed its landform, mainly reducing its surrounding cultivated lands. At present, the residual terraced landscapes are mainly placed in the north side of the city and they represent a kind of “cultural heritage.” On the contrary, the most important garden areas are located in the terrain embankments of the south suburban areas.

scholarly journals Generation of Persistent Scatterers in Non-Urban Areas: The Role of Microwave Scattering Parameters

Geosciences ◽  
2018 ◽  
Vol 8 (7) ◽  
pp. 269 ◽  
Author(s):  
Giovanni Nico ◽  
Sérgio Oliveira ◽  
Joao Catalão ◽  
José Zêzere
Keyword(s):  
Urban Areas ◽  
Ground Surface ◽  
Synthetic Aperture ◽  
Scattering Parameters ◽  
Microwave Scattering ◽  
Sparse Vegetation ◽  
Persistent Scatterers ◽  
Interferometric Phase ◽  
Interferometric Sar

In this work, we study the capability of the ground surface to generate Persistent Scatterers (PS) based on the lithology, slope and aspect angles. These properties affect the scattering behavior of the Synthetic Aperture Radar (SAR) signal, the interferometric phase stability and, as a consequence, the PS generation. Two-time series of interferometric SAR data acquired by two different SAR sensors in the C-band are processed to generate independent PS datasets. The region north of Lisbon, Portugal, characterized by sparse vegetation and lithology diversity, is chosen as study area. The PS frequency distribution is obtained in terms of lithology, slope and aspect angles. This relationship could be useful to estimate the expected PS density in landslide-prone areas, being lithology, slope and aspect angles important landslide predisposing factors.

scholarly journals Detecting Spatiotemporal Features and Rationalities of Urban Expansions within the Guangdong–Hong Kong–Macau Greater Bay Area of China from 1987 to 2017 Using Time-Series Landsat Images and Socioeconomic Data

2019 ◽  
Vol 11 (19) ◽  
pp. 2215 ◽  
Author(s):  
Chao Yang ◽  
Qingquan Li ◽  
Tianhong Zhao ◽  
Huizeng Liu ◽  
Wenxiu Gao ◽  
...  
Keyword(s):  
Hong Kong ◽  
Urban Area ◽  
Urban Areas ◽  
Rural Landscape ◽  
The Other ◽  
Elastic Coefficient ◽  
Landsat Images ◽  
The Sustainable Development ◽  
Bay Area ◽  
Time Periods

The Guangdong–Hong Kong–Macau Greater Bay Area (GBA) of China is one of the major bay areas in the world. However, the spatiotemporal characteristics and rationalities of urban expansions within this region over a relatively long period of time are not well-understood. This study explored the spatiotemporal evolution of 11 cities within the GBA in 1987–2017 by integrating remote sensing, landscape analysis, and geographic information system (GIS) techniques, and further evaluated the rationalities of their expansion using the urban area population elastic coefficient (UPEC) and the urban area gross domestic product (GDP) elastic coefficient (UGEC). The results showed the following: (1) Guangzhou, Shenzhen, Foshan, Dongguan, Zhongshan, and Zhuhai experienced unprecedented urbanization compared with the other cities, and from 1987 to 2017, their urban areas expanded by 10.12, 11.48, 14.21, 24.90, 37.07, and 30.15 times, respectively; (2) several expansion patterns were observed in the 11 cities, including a mononuclear polygon radiation pattern (Guangzhou and Foshan), a double-nucleated polygon pattern (Macau and Zhongshan), and a multi-nuclear urbanization pattern (Shenzhen, Hong Kong, Dongguan, Jiangmen, Huizhou, Zhaoqing, and Zhuhai); (3) with regard to the proportion of area, the edge-expansion and outlying growth types were the predominant types for all 11 cities, and the infilling growth type was the one of the important types during 2007–2017 for Shenzhen, Hong Kong, Dongguan, Zhongshan, and Foshan; (4) the expansion of most cities took on an urban-to-rural landscape gradient, especially for Guangzhou, Shenzhen, Foshan, Zhongshan, Dongguan, and Zhuhai; and (5) the rationalities of expansion in several time periods were rational for Guangzhou (1997–2007), Hong Kong (2007–2017), Foshan (1987–2007), Huizhou (1987–1997), and Dongguan (1997–2007), and the rationalities of expansion in the other cities and time periods were found to be irrational. These findings may help policy- and decision-makers to maintain the sustainable development of the Guangdong–Hong Kong–Macau Greater Bay Area.

scholarly journals PEMBINAAN PERCAKAPAN BAHASA INGGRIS BAGI MASYARAKAT PERUMAHAN GRIYA BATU AJI ASRI BATAM

2020 ◽  
Vol 1 (2) ◽  
pp. 89-94
Author(s):  
Winda Evyanto ◽  
Zia Hisni Mubarak
Keyword(s):  
Foreign Language ◽  
Urban Area ◽  
Community Service ◽  
Urban Areas ◽  
National Language ◽  
The Other ◽  
The People ◽  
The World ◽  
Continuous Activity ◽  
Bahasa Indonesia

English is language that is spoken widely around the world. One of example where English is widely spoken around the country is in Singapore. Not only this country, the neighborhood country such Malaysia has more people who can speak English fluently. For both countries, English is official and second language. While the other neighborhood country such Indonesia uses English less frequently than the national language, Bahasa Indonesia. English is still a foreign language for Indonesian. By looking at this phenomenon, people in our neighboring countries such Singapore and Malaysia use English for their daily conversation. When they want to go to Indonesia, especially to the nearest island from both countries; that is Batam island, sometimes they face that some people in Batam cannot communicate well using English. It happens when they go to some urban areas such as Batu Aji in Batam city. The team of lecturer conducts an activity to the people from an urban area in Batu Aji to be given a community service to teach team how to speak better daily English conversation. The activity is started by training the people vocabulary through the flash card activity. From this activity, people from Griya Batu Aji resident show a good enthusiasm to join the activity to train them better in speaking. This activity is a continuous activity where the team reports the first phase progress of the activity only in this article. 

scholarly journals Detection of Seasonal Deformation of Highway Overpasses Using the PS-InSAR Technique: A Case Study in Beijing Urban Area

2020 ◽  
Vol 12 (18) ◽  
pp. 3071 ◽  
Author(s):  
Mingyuan Lyu ◽  
Yinghai Ke ◽  
Xiaojuan Li ◽  
Lin Zhu ◽  
Lin Guo ◽  
...  
Keyword(s):  
Urban Area ◽  
Urban Areas ◽  
Surface Deformation ◽  
Seasonal Pattern ◽  
Structural Deformation ◽  
Seasonal Patterns ◽  
Persistent Scatterers ◽  
Concentration Degree ◽  
Seasonal Indices

In urban areas, deformation of transportation infrastructures may lead to serious safety accidents. Timely and accurate monitoring of the structural deformation is critical for prevention of transportation accidents and assurance of construction quality, particularly in areas with regional land subsidence, such as the city of Beijing. In this study, we proposed a method for the detection of seasonal deformation of highway overpasses using the integration of persistent scatterers Interferometric Synthetic Aperture Radar (PS-InSAR) techniques and seasonal indices, i.e., deformation concentration degree (DCD) and deformation concentration period (DCP) indices. Taking eastern Beijing urban area as a case study area, we first used the PS-InSAR technique to derive time series surface deformation based on 55 TerraSAR-X images during 2010–2016. Then, we proposed DCD and DCP indices to characterize seasonal deformation of 25 highway overpasses in the study area, with DCD representing to what degree the annual deformation is distributed in a year, and DCP representing the period on which deformation concentrates in the year. Our results showed that the maximum annual deformation rate reached −141.3 mm/year in Beijing urban area, and the PS-InSAR measurements agreed well with levelling measurements (R2 > 0.97). For PS pixels with DCD ≥ 0.3, the monthly deformation showed obvious seasonal patterns with deformation values during some months greater than those during the other months. DCP revealed that the settlement during autumn and winter was more serious than that in spring and summer. The seasonal patterns seemed to be related to the location, structure, and construction age of the overpasses. The upper-level overpasses, the newly constructed overpasses, and those located in the subsidence area (rate < −40 mm/year) tended to show a greater seasonal pattern. The seasonal deformation variations were also affected by groundwater-level fluctuation, temperature, and compressible layer.

The Status of Livelihood Vulnerability and Its CopingCapacities of Urban Squatters in Kathmandu Metropolitan City, Nepal

Patan Pragya ◽  
2019 ◽  
Vol 5 (1) ◽  
pp. 19-32
Author(s):  
Chhabi Ram Baral
Keyword(s):  
Data Collection ◽  
Urban Area ◽  
Urban Areas ◽  
Quantitative Methods ◽  
Urban Poverty ◽  
Rural Poverty ◽  
Poor People ◽  
Qualitative And Quantitative ◽  
Qualitative And Quantitative Methods ◽  
The Status

Urban poverty is one of multidimensional issue in Nepal. Increasing immigration from the outer parts of Kathmandu due to rural poverty, unemployment and weak security of the lives and the properties are core causes pushing people into urban areas. In this context how squatter urban area people sustain their livelihoods is major concern. The objectives of the study are to find out livelihood assets and capacities squatters coping with their livelihood vulnerability in adverse situation. Both qualitative and quantitative methods are applied for data collection. It is found that squatters social security is weak, victimized by severe health problems earning is not regular with lack of physical facilities and overall livelihood is critical. This study helps to understand what the changes that have occurred in livelihood patterns and how poor people survive in urban area.

scholarly journals The Wood Quality of Small-Leaved Lime (Tilia cordata Mill.) Trees in an Urban Area: A Pilot Study

Forests ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 420
Author(s):  
Benas Šilinskas ◽  
Aistė Povilaitienė ◽  
Gintautas Urbaitis ◽  
Marius Aleinikovas ◽  
Iveta Varnagirytė-Kabašinskienė
Keyword(s):  
Urban Area ◽  
Urban Areas ◽  
Wood Quality ◽  
Wood Products ◽  
Urban Trees ◽  
Measuring System ◽  
Forest Site ◽  
Tilia Cordata ◽  
Mean Values ◽  
Wood Development

This study performed a pilot evaluation of the wood quality—defined by a single parameter: dynamic modulus of elasticity (MOEdyn, N mm−2)—of small-leaved lime (Tilia cordata Mill.) trees in urban areas. A search of the literature revealed few studies which examined the specifics of tree wood development in urban areas. Little is known about the potential of wood from urban trees wood of their suitability for the timber industry. In this study, an acoustic velocity measuring system was used for wood quality assessment of small-leaved lime trees. The MOEdyn parameter was evaluated for small-leaved lime trees growing in two urban locations (along the streets, and in an urban park), with an additional sample of forest sites taken as the control. MOEdyn was also assessed for small-leaved lime trees visually assigned to different health classes. The obtained mean values of MOEdyn of 90–120-year old small-leaved lime trees in urban areas ranged between 2492.2 and 2715.8 N mm−2. For younger trees, the values of MOEdyn were lower in the urban areas than in the forest site. Otherwise, the results of the study showed that the small-leaved lime wood samples were of relatively good quality, even if the tree was classified as moderately damaged (which could cause a potential risk to the community). Two alternatives for urban tree management can be envisaged: (1) old trees could be left to grow to maintain the sustainability of an urban area until their natural death, or (2) the wood from selected moderately damaged trees could be used to create wood products, ensuring long-term carbon retention.

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