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A special issue of Sensors (ISSN 1424-8220). This special issue belongs to the section "Remote Sensors".

Deadline for manuscript submissions: closed (31 March 2008)

Special Issue Editor

Guest Editor
Prof. Dr. Jiang Dong

Data Center for Resources and Environmental Sciences, Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, P.O.Box 9719, 11A Datun Road, Chao Yang District 100101, Beijing, China
E-Mail
Interests: remote sensing of resources and environment; geographical information system

Special Issue Information

Dear Colleagues,

Urbanization is one of the most powerful and visible anthropogenic force on the earth (Philip R. Christensen., etc.2003). Rapid urbanization procession exerts great influences on the regional and global environment, so that monitoring spatiotemporal dynamics of urban environment will become increasingly important. Satellite and airborne sensors can provide multi-temporal and multi-spatial information for urban environmental monitoring. Accordingly, the special issue of 'Sensors for Urban Environmental Monitoring' encourages papers on the use of remotely sensed data for key urban environmental quantities measurement, urban growth simulation, urban ecosystem structure and function assessment.

Prof. Dr. Jiang Dong
Guest Editor

Keywords

  • urban environmental monitoring
  • remote sensing
  • urban land cover classification
  • urban growth
  • urban heat island effect
  • urban climate models
  • image fusion / data assimilation

Published Papers (24 papers)

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Research

Open AccessArticle Analysis of Land Use Change and Urbanization in the Kucukcekmece Water Basin (Istanbul, Turkey) with Temporal Satellite Data using Remote Sensing and GIS
Sensors 2008, 8(11), 7213-7223; doi:10.3390/s8117213
Received: 27 September 2008 / Revised: 15 October 2008 / Accepted: 11 November 2008 / Published: 13 November 2008
Cited by 12 | PDF Full-text (817 KB) | HTML Full-text | XML Full-text
Abstract
Accurate and timely information about land use and land cover (LULC) and its changes in urban areas are crucial for urban land management decision-making, ecosystem monitoring and urban planning. Also, monitoring and representation of urban sprawl and its effects on the LULC patterns
[...] Read more.
Accurate and timely information about land use and land cover (LULC) and its changes in urban areas are crucial for urban land management decision-making, ecosystem monitoring and urban planning. Also, monitoring and representation of urban sprawl and its effects on the LULC patterns and hydrological processes of an urbanized watershed is an essential part of water resource planning and management. This paper presents an image analysis study using multi temporal digital satellite imagery of LULC and changes in the Kucukcekmece Watershed (Metropolitan Istanbul, Turkey) from 1992 to 2006. The Kucukcekmece Basin includes portions of the Kucukcekmece District within the municipality of Istanbul so it faces a dramatic urbanization. An urban monitoring analysis approach was first used to implement a land cover classification. A change detection method controlled with ground truth information was then used to determine changes in land cover. During the study period, the variability and magnitude of hydrological components based on land-use patterns were cumulatively influenced by urban sprawl in the watershed. The proposed approach, which uses a combination of Remote Sensing (RS) and Geographical Information System (GIS) techniques, is an effective tool that enhances land-use monitoring, planning, and management of urbanized watersheds. Full article
(This article belongs to the Special Issue Sensors for Urban Environmental Monitoring)
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Open AccessArticle Comparative and Combinative Study of Urban Heat island in Wuhan City with Remote Sensing and CFD Simulation
Sensors 2008, 8(10), 6692-6703; doi:10.3390/s8106692
Received: 26 March 2008 / Revised: 28 September 2008 / Accepted: 21 October 2008 / Published: 25 October 2008
Cited by 11 | PDF Full-text (541 KB) | HTML Full-text | XML Full-text
Abstract
Urban heat islands are one of the most critical urban environment heat problems. Landsat ETM+ satellite data were used to investigate the land surface temperature and underlying surface indices such as NDVI and NDBI. A comparative study of the urban heat environment at
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Urban heat islands are one of the most critical urban environment heat problems. Landsat ETM+ satellite data were used to investigate the land surface temperature and underlying surface indices such as NDVI and NDBI. A comparative study of the urban heat environment at different scales, times and locations was done to verify the heat island characteristics. Since remote sensing technology has limitations for dynamic flow analysis in the study of urban spaces, a CFD simulation was used to validate the improvement of the heat environment in a city by means of wind. CFD technology has its own shortcomings in parameter setting and verification, while RS technology is helpful to remedy this. The city of Wuhan and its climatological condition of being hot in summer and cold in winter were chosen to verify the comparative and combinative application of RS with CFD in studying the urban heat island. Full article
(This article belongs to the Special Issue Sensors for Urban Environmental Monitoring)
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Open AccessArticle Surface Heat Balance Analysis of Tainan City on March 6, 2001 Using ASTER and Formosat-2 Data
Sensors 2008, 8(9), 6026-6044; doi:10.3390/s8096026
Received: 1 September 2008 / Revised: 18 September 2008 / Accepted: 24 September 2008 / Published: 26 September 2008
Cited by 14 | PDF Full-text (2862 KB) | HTML Full-text | XML Full-text
Abstract
The urban heat island phenomenon occurs as a mixed result of anthropogenic heat discharge, decreased vegetation, and increased artificial impervious surfaces. To clarify the contribution of each factor to the urban heat island, it is necessary to evaluate the surface heat balance. Satellite
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The urban heat island phenomenon occurs as a mixed result of anthropogenic heat discharge, decreased vegetation, and increased artificial impervious surfaces. To clarify the contribution of each factor to the urban heat island, it is necessary to evaluate the surface heat balance. Satellite remote sensing data of Tainan City, Taiwan, obtained from Terra ASTER and Formosat-2 were used to estimate surface heat balance in this study. ASTER data is suitable for analyzing heat balance because of the wide spectral range. We used Formosat-2 multispectral data to classify the land surface, which was used to interpolate some surface parameters for estimating heat fluxes. Because of the high spatial resolution of the Formosat-2 image, more roads, open spaces and small vegetation areas could be distinguished from buildings in urban areas; however, misclassifications of land cover in such areas using ASTER data would overestimate the sensible heat flux. On the other hand, the small vegetated areas detected from the Formosat-2 image slightly increased the estimation of latent heat flux. As a result, the storage heat flux derived from Formosat-2 is higher than that derived from ASTER data in most areas. From these results, we can conclude that the higher resolution land coverage map increases accuracy of the heat balance analysis. Storage heat flux occupies about 60 to 80% of the net radiation in most of the artificial surface areas in spite of their usages. Because of the homogeneity of the building roof materials, there is no contrast between the storage heat flux in business and residential areas. In sparsely vegetated urban areas, more heat is stored and latent heat is smaller than that in the forested suburbs. This result implies that density of vegetation has a significant influence in decreasing temperatures. Full article
(This article belongs to the Special Issue Sensors for Urban Environmental Monitoring)
Open AccessArticle Integrated Evaluation of Urban Development Suitability Based on Remote Sensing and GIS Techniques – A Case Study in Jingjinji Area, China
Sensors 2008, 8(9), 5975-5986; doi:10.3390/s8095975
Received: 27 July 2008 / Revised: 15 September 2008 / Accepted: 20 September 2008 / Published: 25 September 2008
Cited by 26 | PDF Full-text (220 KB) | HTML Full-text | XML Full-text | Correction | Supplementary Files
Abstract
Jingjinji area (namely Beijing, Tianjin and He Bei Province) is one of the three largest regional economic communities in China. Urban expansion has sped up in the past 20 years in this area due to the rapid economic and population growth. Evaluating the
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Jingjinji area (namely Beijing, Tianjin and He Bei Province) is one of the three largest regional economic communities in China. Urban expansion has sped up in the past 20 years in this area due to the rapid economic and population growth. Evaluating the landuse suitability for urban growth on a regional scale is an urgent need, because the most suitable areas and the most suitable scale of urban growth can thus be determined accordingly. In order to meet this requirement, remote sensing and geographic information system (GIS) techniques were adopted, and an integrated evaluating model was developed supported by AHP method. The integrated urban development suitability index (UDSI) was calculated using this model. According to the UDSI result, the spatial distribution of urban development suitability and its driving forces were analyzed. Urban boundaries in 1995, 2000 and 2005, which were derived from Landsat TM/ETM+ satellite data, were overlaid on the UDSI map, and the suitable urban develop tendency in this area were discussed. The result of this study indicated that integrated evaluation of urban development could be conducted in an operational way using remote sensing data, GIS spatial analysis technique and AHP modeling method. Full article
(This article belongs to the Special Issue Sensors for Urban Environmental Monitoring)
Open AccessArticle Analyzing Land Use Changes in the Metropolitan Jilin City of Northeastern China Using Remote Sensing and GIS
Sensors 2008, 8(9), 5449-5465; doi:10.3390/s8095449
Received: 20 July 2008 / Revised: 1 September 2008 / Accepted: 1 September 2008 / Published: 3 September 2008
Cited by 1 | PDF Full-text (471 KB) | HTML Full-text | XML Full-text
Abstract
Remote sensing and GIS have been widely employed to study temporal and spatial urban land use changes in southern and southeastern China. However, few studies have been conducted in northeastern regions. This study analyzed land use change and spatial patterns of urban expansion
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Remote sensing and GIS have been widely employed to study temporal and spatial urban land use changes in southern and southeastern China. However, few studies have been conducted in northeastern regions. This study analyzed land use change and spatial patterns of urban expansion in the metropolitan area of Jilin City, located on the extension of Changbai Mountain, based on aerial photos from 1989 and 2005 Spot images. The results indicated that urban land and transportation land increased dramatically (by 94.04% and 211.20%, respectively); isolated industrial and mining land decreased moderately (by 29.54%); rural residential land increased moderately (by 26.48%); dry land and paddy fields increased slightly (by 15.68% and 11.78%, respectively); forest and orchards decreased slightly (by 5.27% and 4.61%, respectively); grasslands and unused land decreased dramatically (by 99.12% and 86.04%, respectively). Sloped dry land (more than 4 degrees) was mainly distributed on the land below 10 degrees with an east, southeastern and south sunny direction aspect, and most sloped dry land transformed to forest was located on an east aspect lower than 12 degrees, while forest changed to dry land were mainly distributed on east and south aspects lower than 10 degrees. A spatial dependency analysis of land use change showed that the increased urban land was a logarithmic function of distance to the Songhua River. This study also provided some data with spatial details about the uneven land development in the upstream areas of Songhua River basin. Full article
(This article belongs to the Special Issue Sensors for Urban Environmental Monitoring)
Open AccessArticle Chemical Characterization of Dew Water Collected in Different Geographic Regions of Poland
Sensors 2008, 8(6), 4006-4032; doi:10.3390/s8064006
Received: 23 May 2008 / Accepted: 19 June 2008 / Published: 25 June 2008
Cited by 20 | PDF Full-text (585 KB) | HTML Full-text | XML Full-text
Abstract
The results of a dew monitoring program performed in Poland with the aim to outline the chemical composition of dew water in meteorological context are presented. Dew samples were collected from eight measurement stations from August 2004 to November 2006. Taking into account
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The results of a dew monitoring program performed in Poland with the aim to outline the chemical composition of dew water in meteorological context are presented. Dew samples were collected from eight measurement stations from August 2004 to November 2006. Taking into account the type of land use and characteristics of pollutant emission, sampling sites were divided into the following categories: rural, coastal urban and inland urban stations. Selected anions and cations as well as formaldehyde and sum of phenols were determined. The average TIC (Total Inorganic Ionic Content) values in dew samples ranged from 0.83 to 3.93 between individual stations with 10.9 meq/L as the highest daily value of TIC measured. The average TIC values observed in dew at all stations were at a similar level (2.46 meq/L) when compared with hoarfrost (2.86 meq/L). However, these values were much higher in comparison with other kinds of atmospheric water like precipitation (wet only; 0.37 meq/L) or fog/cloud (1.01 meq/L). The pH values of dew water ranged from 5.22 to 7.35 for urban coastal stations, from 5.67 to 8.02 for urban inland stations and from 4.16 to 8.76 for dew samples collected in the rural area. HCHO was found in 97 % of dew samples, with concentrations ranging from 0.010 to 5.40 meq/L. Excluding stations near the seashore, where the contribution of Na+ and Cl- increased, the most important ions were sulphates. A very low contribution of NO3- and noticeable increase of Ca2+ which were not observed in the case of precipitation and fog water, were typical in all stations. The contribution of ammonium ion was two times higher at rural stations as a result of agricultural ammonia emissions. The strongest correlations were noticed between the sum of acidifying anions SO42- + NO3- and Ca2+ ion for all urban and rural stations. A very strong correlation was also observed for Na+ and Cl- ions in urban coastal stations, as a natural consequence of the location of these stations close to the sea. It was proved that thermal stratification, direction of circulation and local breeze circulation control the atmospheric chemistry at ground level, where dew is formed. The highest TIC values at urban stations were associated with anticyclonic weather, while at rural sites with cyclonic weather situations. The chemistry of dew water in urban coastal stations was closely related to local breeze circulation in the warm season, mainly in the form of diurnal breeze causing a significant increase of the concentration of Na+ and Cl-ions. Thus, dew can be a good indicator of the atmospheric pollution level at a given site. Taking into account both high TIC values and the annual water equivalent estimated at around 50 mm, dew is a considerable factor of wet deposition, responsible for an additional 60 % of pollutant input into the ground when compared with precipitation. Full article
(This article belongs to the Special Issue Sensors for Urban Environmental Monitoring)
Open AccessArticle Comparing Different Approaches for Mapping Urban Vegetation Cover from Landsat ETM+ Data: A Case Study on Brussels
Sensors 2008, 8(6), 3880-3902; doi:10.3390/s8063880
Received: 2 April 2008 / Revised: 28 May 2008 / Accepted: 30 May 2008 / Published: 10 June 2008
Cited by 28 | PDF Full-text (537 KB) | HTML Full-text | XML Full-text
Abstract
Urban growth and its related environmental problems call for sustainable urban management policies to safeguard the quality of urban environments. Vegetation plays an important part in this as it provides ecological, social, health and economic benefits to a city’s inhabitants. Remotely sensed data
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Urban growth and its related environmental problems call for sustainable urban management policies to safeguard the quality of urban environments. Vegetation plays an important part in this as it provides ecological, social, health and economic benefits to a city’s inhabitants. Remotely sensed data are of great value to monitor urban green and despite the clear advantages of contemporary high resolution images, the benefits of medium resolution data should not be discarded. The objective of this research was to estimate fractional vegetation cover from a Landsat ETM+ image with sub-pixel classification, and to compare accuracies obtained with multiple stepwise regression analysis, linear spectral unmixing and multi-layer perceptrons (MLP) at the level of meaningful urban spatial entities. Despite the small, but nevertheless statistically significant differences at pixel level between the alternative approaches, the spatial pattern of vegetation cover and estimation errors is clearly distinctive at neighbourhood level. At this spatially aggregated level, a simple regression model appears to attain sufficient accuracy. For mapping at a spatially more detailed level, the MLP seems to be the most appropriate choice. Brightness normalisation only appeared to affect the linear models, especially the linear spectral unmixing. Full article
(This article belongs to the Special Issue Sensors for Urban Environmental Monitoring)
Open AccessArticle Spatio-Temporal Modelling of Dust Transport over Surface Mining Areas and Neighbouring Residential Zones
Sensors 2008, 8(6), 3830-3847; doi:10.3390/s8063830
Received: 25 January 2008 / Revised: 26 May 2008 / Accepted: 27 May 2008 / Published: 6 June 2008
Cited by 12 | PDF Full-text (3434 KB) | HTML Full-text | XML Full-text
Abstract
Projects focusing on spatio-temporal modelling of the living environment need to manage a wide range of terrain measurements, existing spatial data, time series, results of spatial analysis and inputs/outputs from numerical simulations. Thus, GISs are often used to manage data from remote sensors,
[...] Read more.
Projects focusing on spatio-temporal modelling of the living environment need to manage a wide range of terrain measurements, existing spatial data, time series, results of spatial analysis and inputs/outputs from numerical simulations. Thus, GISs are often used to manage data from remote sensors, to provide advanced spatial analysis and to integrate numerical models. In order to demonstrate the integration of spatial data, time series and methods in the framework of the GIS, we present a case study focused on the modelling of dust transport over a surface coal mining area, exploring spatial data from 3D laser scanners, GPS measurements, aerial images, time series of meteorological observations, inputs/outputs form numerical models and existing geographic resources. To achieve this, digital terrain models, layers including GPS thematic mapping, and scenes with simulation of wind flows are created to visualize and interpret coal dust transport over the mine area and a neighbouring residential zone. A temporary coal storage and sorting site, located near the residential zone, is one of the dominant sources of emissions. Using numerical simulations, the possible effects of wind flows are observed over the surface, modified by natural objects and man-made obstacles. The coal dust drifts with the wind in the direction of the residential zone and is partially deposited in this area. The simultaneous display of the digital map layers together with the location of the dominant emission source, wind flows and protected areas enables a risk assessment of the dust deposition in the area of interest to be performed. In order to obtain a more accurate simulation of wind flows over the temporary storage and sorting site, 3D laser scanning and GPS thematic mapping are used to create a more detailed digital terrain model. Thus, visualization of wind flows over the area of interest combined with 3D map layers enables the exploration of the processes of coal dust deposition at a local scale. In general, this project could be used as a template for dust-transport modelling which couples spatial data focused on the construction of digital terrain models and thematic mapping with data generated by numerical simulations based on Reynolds averaged Navier-Stokes equations. Full article
(This article belongs to the Special Issue Sensors for Urban Environmental Monitoring)
Open AccessArticle Air Pollution Monitoring and Mining Based on Sensor Grid in London
Sensors 2008, 8(6), 3601-3623; doi:10.3390/s80603601
Received: 1 April 2008 / Revised: 22 May 2008 / Accepted: 23 May 2008 / Published: 1 June 2008
Cited by 8 | PDF Full-text (1921 KB) | HTML Full-text | XML Full-text
Abstract
In this paper, we present a distributed infrastructure based on wireless sensors network and Grid computing technology for air pollution monitoring and mining, which aims to develop low-cost and ubiquitous sensor networks to collect real-time, large scale and comprehensive environmental data from road
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In this paper, we present a distributed infrastructure based on wireless sensors network and Grid computing technology for air pollution monitoring and mining, which aims to develop low-cost and ubiquitous sensor networks to collect real-time, large scale and comprehensive environmental data from road traffic emissions for air pollution monitoring in urban environment. The main informatics challenges in respect to constructing the high-throughput sensor Grid are discussed in this paper. We present a twolayer network framework, a P2P e-Science Grid architecture, and the distributed data mining algorithm as the solutions to address the challenges. We simulated the system in TinyOS to examine the operation of each sensor as well as the networking performance. We also present the distributed data mining result to examine the effectiveness of the algorithm. Full article
(This article belongs to the Special Issue Sensors for Urban Environmental Monitoring)
Open AccessArticle Hyperspectral Sensor Data Capability for Retrieving Complex Urban Land Cover in Comparison with Multispectral Data: Venice City Case Study (Italy)
Sensors 2008, 8(5), 3299-3320; doi:10.3390/s8053299
Received: 17 April 2008 / Accepted: 15 May 2008 / Published: 20 May 2008
Cited by 24 | PDF Full-text (1209 KB) | HTML Full-text | XML Full-text
Abstract
This study aims at comparing the capability of different sensors to detect land cover materials within an historical urban center. The main objective is to evaluate the added value of hyperspectral sensors in mapping a complex urban context. In this study we used:
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This study aims at comparing the capability of different sensors to detect land cover materials within an historical urban center. The main objective is to evaluate the added value of hyperspectral sensors in mapping a complex urban context. In this study we used: (a) the ALI and Hyperion satellite data, (b) the LANDSAT ETM+ satellite data, (c) MIVIS airborne data and (d) the high spatial resolution IKONOS imagery as reference. The Venice city center shows a complex urban land cover and therefore was chosen for testing the spectral and spatial characteristics of different sensors in mapping the urban tissue. For this purpose, an object-oriented approach and different common classification methods were used. Moreover, spectra of the main anthropogenic surfaces (i.e. roofing and paving materials) were collected during the field campaigns conducted on the study area. They were exploited for applying band-depth and sub-pixel analyses to subsets of Hyperion and MIVIS hyperspectral imagery. The results show that satellite data with a 30m spatial resolution (ALI, LANDSAT ETM+ and HYPERION) are able to identify only the main urban land cover materials. Full article
(This article belongs to the Special Issue Sensors for Urban Environmental Monitoring)
Open AccessArticle Analyzing the Variation of Building Density Using High Spatial Resolution Satellite Images: the Example of Shanghai City
Sensors 2008, 8(4), 2541-2550; doi:10.3390/s8042541
Received: 10 December 2007 / Accepted: 31 March 2008 / Published: 11 April 2008
Cited by 19 | PDF Full-text (1457 KB) | HTML Full-text | XML Full-text
Abstract
Building density is an important issue in urban planning and land management. In the article, building coverage ratio (BCR) and floor area ratio (FAR) values extracted from high resolution satellite images were used to indicate buildings’ stretching on the surface and growth along
[...] Read more.
Building density is an important issue in urban planning and land management. In the article, building coverage ratio (BCR) and floor area ratio (FAR) values extracted from high resolution satellite images were used to indicate buildings’ stretching on the surface and growth along the third dimension within areas of interest in Shanghai City, P.R. China. The results show that the variation of FAR is higher than that of BCR in the inner circle, and that the newer commercial centers have higher FAR and lower BCR values, while the traditional commercial areas have higher FAR and BCR ratios. By comparing different residential areas, it was found that the historical “Shikumen” areas and the old residential areas built before 1980s have higher BCR and lower FAR, while the new residential areas have higher FAR and lower BCR, except for the villa areas. These results suggest that both older building areas and villa areas use land resources in an inefficient way, and therefore better planning and management of urban land are needed for those fast economic growing regions. Full article
(This article belongs to the Special Issue Sensors for Urban Environmental Monitoring)
Open AccessArticle Rapid Urbanization and Implications for Flood Risk Management in Hinterland of the Pearl River Delta, China: The Foshan Study
Sensors 2008, 8(4), 2223-2239; doi:10.3390/s8042223
Received: 31 December 2007 / Accepted: 7 March 2008 / Published: 28 March 2008
Cited by 21 | PDF Full-text (367 KB) | HTML Full-text | XML Full-text
Abstract
The purpose of this paper is to examine the linkage between rapid urbanization and flood risk in the hinterlands of the Pearl River Delta, P.R. China. Foshan, a typical hinterland city in the Pearl River Delta region, was selected as a case study.
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The purpose of this paper is to examine the linkage between rapid urbanization and flood risk in the hinterlands of the Pearl River Delta, P.R. China. Foshan, a typical hinterland city in the Pearl River Delta region, was selected as a case study. Land use and cover change in Foshan during 1988-2003 was analyzed using remote sensing and geographic information system (GIS) techniques. Furthermore, analysis on historical hydrological data during 1962-2005 was performed. Results show that rapid urbanization has resulted in losses of farmland, forest and shrub since 1988. In addition, in order to compensate or offset the loss of farmland due to rapid urban expansion, more than 30 % of the forest and 20 % of the shrub areas were transformed into farmlands. Inevitably, both the urban and agricultural lands increased the pressure on the drainage systems. Furthermore, over the past decades human activities such as dredging up the floodways, excavating sand and building water facilities in the rivers, significantly changed the hydrological conditions, and therefore impaired the rivers’ capacity to buffer floods. Lessons from the Foshan case implied that, in addition to natural processes, human activities driven by socio-economic factors should be considered responsible for the recently increasing level of flood risks. Both economically and environmentally, it is irrational and impractical to encourage encroachment of lands vulnerable to floods. It is also realistic and urgent to effectively prevent and control the adverse ecological consequences of urbanization and economic activities for building their wealth and prominence. Full article
(This article belongs to the Special Issue Sensors for Urban Environmental Monitoring)
Open AccessArticle Object-based Land Cover Classification and Change Analysis in the Baltimore Metropolitan Area Using Multitemporal High Resolution Remote Sensing Data
Sensors 2008, 8(3), 1613-1636; doi:10.3390/s8031613
Received: 29 January 2008 / Accepted: 28 February 2008 / Published: 10 March 2008
Cited by 84 | PDF Full-text (801 KB) | HTML Full-text | XML Full-text
Abstract
Accurate and timely information about land cover pattern and change in urbanareas is crucial for urban land management decision-making, ecosystem monitoring andurban planning. This paper presents the methods and results of an object-basedclassification and post-classification change detection of multitemporal high-spatialresolution Emerge aerial imagery
[...] Read more.
Accurate and timely information about land cover pattern and change in urbanareas is crucial for urban land management decision-making, ecosystem monitoring andurban planning. This paper presents the methods and results of an object-basedclassification and post-classification change detection of multitemporal high-spatialresolution Emerge aerial imagery in the Gwynns Falls watershed from 1999 to 2004. TheGwynns Falls watershed includes portions of Baltimore City and Baltimore County,Maryland, USA. An object-based approach was first applied to implement the land coverclassification separately for each of the two years. The overall accuracies of theclassification maps of 1999 and 2004 were 92.3% and 93.7%, respectively. Following theclassification, we conducted a comparison of two different land cover change detectionmethods: traditional (i.e., pixel-based) post-classification comparison and object-basedpost-classification comparison. The results from our analyses indicated that an objectbasedapproach provides a better means for change detection than a pixel based methodbecause it provides an effective way to incorporate spatial information and expertknowledge into the change detection process. The overall accuracy of the change mapproduced by the object-based method was 90.0%, with Kappa statistic of 0.854, whereasthe overall accuracy and Kappa statistic of that by the pixel-based method were 81.3% and0.712, respectively. Full article
(This article belongs to the Special Issue Sensors for Urban Environmental Monitoring)
Open AccessArticle Road Asphalt Pavements Analyzed by Airborne Thermal Remote Sensing: Preliminary Results of the Venice Highway
Sensors 2008, 8(2), 1278-1296; doi:10.3390/s8021278
Received: 5 February 2008 / Accepted: 21 February 2008 / Published: 22 February 2008
Cited by 13 | PDF Full-text (1159 KB) | HTML Full-text | XML Full-text
Abstract
This paper describes a fast procedure for evaluating asphalt pavement surface defects using airborne emissivity data. To develop this procedure, we used airborne multispectral emissivity data covering an urban test area close to Venice (Italy).For this study, we first identify and select the
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This paper describes a fast procedure for evaluating asphalt pavement surface defects using airborne emissivity data. To develop this procedure, we used airborne multispectral emissivity data covering an urban test area close to Venice (Italy).For this study, we first identify and select the roads’ asphalt pavements on Multispectral Infrared Visible Imaging Spectrometer (MIVIS) imagery using a segmentation procedure. Next, since in asphalt pavements the surface defects are strictly related to the decrease of oily components that cause an increase of the abundance of surfacing limestone, the diagnostic absorption emissivity peak at 11.2μm of the limestone was used for retrieving from MIVIS emissivity data the areas exhibiting defects on asphalt pavements surface.The results showed that MIVIS emissivity allows establishing a threshold that points out those asphalt road sites on which a check for a maintenance intervention is required. Therefore, this technique can supply local government authorities an efficient, rapid and repeatable road mapping procedure providing the location of the asphalt pavements to be checked. Full article
(This article belongs to the Special Issue Sensors for Urban Environmental Monitoring)
Open AccessArticle Using Geospatial Information Technology in Natural Resources Management: The Case of Urban Land Management In West Africa
Sensors 2008, 8(2), 607-619; doi:10.3390/s8020607
Received: 4 December 2007 / Accepted: 21 January 2008 / Published: 4 February 2008
Cited by 1 | PDF Full-text (1928 KB) | HTML Full-text | XML Full-text
Abstract
In the past several decades, Lagos Metropolis emerged as one of the fastesturbanizing cities in the West African Sub-region. In the absence of a regular use ofgeospatial information management systems, limited effort had been made to keep track ofchanges in the natural environment
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In the past several decades, Lagos Metropolis emerged as one of the fastesturbanizing cities in the West African Sub-region. In the absence of a regular use ofgeospatial information management systems, limited effort had been made to keep track ofchanges in the natural environment in the rapidly growing city for policy making in landadministration. The ubiquitous energy radiated by the rapid urbanization rate in the areanot only created unprecedented consequences by diminishing the quality of theenvironment and natural resources but it raises serious implications for land managementin the region. The factors fuelling the land crisis in the area which are not far fetchedconsists of socio-economic, ecological and policy elements. To tackle these issues in amega city, up-to-date knowledge would be required to capture and analyze landinformation trends. Such an effort will help manage the city’s expansion as well asinfrastructure development through the right choices in planning and (spatial) designsusing the latest tools in geospatial technologies of Geographic Information Systems GIS)and remote sensing. This study investigates the spatial implications of the rapid expansionof metropolitan Lagos for land management using GIS and Remote sensing technology.The result of the research provides a valuable road map that can enable planners contributeto improved land administration necessary for effective management of natural resources. Full article
(This article belongs to the Special Issue Sensors for Urban Environmental Monitoring)
Open AccessArticle Monitoring and Predicting Land-use Changes and the Hydrology of the Urbanized Paochiao Watershed in Taiwan Using Remote Sensing Data, Urban Growth Models and a Hydrological Model
Sensors 2008, 8(2), 658-680; doi:10.3390/s8020658
Received: 10 December 2007 / Accepted: 29 January 2008 / Published: 4 February 2008
Cited by 18 | PDF Full-text (2966 KB) | HTML Full-text | XML Full-text
Abstract
Monitoring and simulating urban sprawl and its effects on land-use patterns andhydrological processes in urbanized watersheds are essential in land-use and waterresourceplanning and management. This study applies a novel framework to the urbangrowth model Slope, Land use, Excluded land, Urban extent, Transportation, andHillshading
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Monitoring and simulating urban sprawl and its effects on land-use patterns andhydrological processes in urbanized watersheds are essential in land-use and waterresourceplanning and management. This study applies a novel framework to the urbangrowth model Slope, Land use, Excluded land, Urban extent, Transportation, andHillshading (SLEUTH) and land-use change with the Conversion of Land use and itsEffects (CLUE-s) model using historical SPOT images to predict urban sprawl in thePaochiao watershed in Taipei County, Taiwan. The historical and predicted land-use datawas input into Patch Analyst to obtain landscape metrics. This data was also input to theGeneralized Watershed Loading Function (GWLF) model to analyze the effects of futureurban sprawl on the land-use patterns and watershed hydrology. The landscape metrics ofthe historical SPOT images show that land-use patterns changed between 1990–2000. TheSLEUTH model accurately simulated historical land-use patterns and urban sprawl in thePaochiao watershed, and simulated future clustered land-use patterns (2001–2025). TheCLUE-s model also simulated land-use patterns for the same period and yielded historical trends in the metrics of land-use patterns. The land-use patterns predicted by the SLEUTHand CLUE-s models show the significant impact urban sprawl will have on land-usepatterns in the Paochiao watershed. The historical and predicted land-use patterns in thewatershed tended to fragment, had regular shapes and interspersion patterns, but wererelatively less isolated in 2001–2025 and less interspersed from 2005–2025 compared withland-use pattern in 1990. During the study, the variability and magnitude of hydrologicalcomponents based on the historical and predicted land-use patterns were cumulativelyaffected by urban sprawl in the watershed; specifically, surface runoff increasedsignificantly by 22.0% and baseflow decreased by 18.0% during 1990–2025. The proposedapproach is an effective means of enhancing land-use monitoring and management ofurbanized watersheds. Full article
(This article belongs to the Special Issue Sensors for Urban Environmental Monitoring)
Open AccessArticle Analysis of Urban-Rural Land-Use Change during 1995-2006 and Its Policy Dimensional Driving Forces in Chongqing, China
Sensors 2008, 8(2), 681-699; doi:10.3390/s8020681
Received: 26 December 2007 / Accepted: 29 January 2008 / Published: 4 February 2008
Cited by 31 | PDF Full-text (2101 KB) | HTML Full-text | XML Full-text
Abstract
This paper analyzes the urban-rural land-use change of Chongqing and its policydimensional driving forces from 1995 to 2006, using high-resolution Landsat TM(Thematic Mapper) data of 1995, 2000 and 2006, and socio-economic data from bothresearch institutes and government departments. The outcomes indicated that urban-ruralland-use
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This paper analyzes the urban-rural land-use change of Chongqing and its policydimensional driving forces from 1995 to 2006, using high-resolution Landsat TM(Thematic Mapper) data of 1995, 2000 and 2006, and socio-economic data from bothresearch institutes and government departments. The outcomes indicated that urban-ruralland-use change in Chongqing can be characterized by two major trends: First, thenon-agricultural land increased substantially from 1995 to 2006, thus causing agriculturalland especially farmland to decrease continuously. Second, the aggregation index of urbansettlements and rural settlements shows that local urban-rural development experienced aprocess of changing from aggregation (1995-2000) to decentralization (2000-2006).Chongqing is a special area getting immersed in many important policies, which includethe establishment of the municipality directly under the Central Government, the buildingof Three Gorges Dam Project, the Western China Development Program and theGrain-for-Green Programme, and bring about tremendous influences on its land-usechange. By analyzing Chongqing’s land-use change and its policy driving forces, someimplications for its new policy of ‘Urban-rural Integrated Reform’ are obtained. That ismore attentions need to be paid to curbing excessive and idle rural housing andconsolidating rural construction land, and to laying out a scientific land-use plan for its rural areas taking such rural land-use issues as farmland occupation and rural housing landmanagement into accounts, so as to coordinate and balance the urban-rural development. Full article
(This article belongs to the Special Issue Sensors for Urban Environmental Monitoring)
Open AccessArticle Application of Multiplexed FBG and PZT Impedance Sensors for Health Monitoring of Rocks
Sensors 2008, 8(1), 271-289; doi:10.3390/s8010271
Received: 23 December 2007 / Accepted: 11 January 2008 / Published: 21 January 2008
Cited by 35 | PDF Full-text (1122 KB) | HTML Full-text | XML Full-text
Abstract
Reliable structural health monitoring (SHM) including nondestructiveevaluation (NDE) is essential for safe operation of infrastructure systems. Effectivemonitoring of the rock components of civil infrastructures such as tunnels and cavernsremains challenging. The feasibility of employing smart optical fibre sensor (OFS) andpiezoelectric impedance sensor made
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Reliable structural health monitoring (SHM) including nondestructiveevaluation (NDE) is essential for safe operation of infrastructure systems. Effectivemonitoring of the rock components of civil infrastructures such as tunnels and cavernsremains challenging. The feasibility of employing smart optical fibre sensor (OFS) andpiezoelectric impedance sensor made up of lead zirconate titanate (PZT) forcomprehensive health monitoring of rocks, covering load history monitoring/retrieval aswell as damage assessment is presented in this paper. The rock specimens are subjected tocyclic loading and their conditions are continuously monitored using OFS and PZTsensors. OFS based multiplexed fibre Bragg grating (FBG) sensors are surface bonded onthe rock specimens. Their strain sensing performance is compared with the conventionalelectric strain gauges (ESGs). In addition, PZT patches are also bonded on the specimensto study the damage pattern during different loading cycles. Unlike the FBGs or ESGs,PZT patches are used as bi-functional sensors and actuators, enabling them to be efficientdetectors of incipient damages using the principle of electromechanical impedance. Theexperimental study demonstrated superior performance of these smart FBG and PZTimpedance sensors. This work is expected to be useful for SHM based NDE application ofrock structures such as caverns and tunnels. Full article
(This article belongs to the Special Issue Sensors for Urban Environmental Monitoring)
Open AccessArticle Sensitivity of PZT Impedance Sensors for Damage Detection of Concrete Structures
Sensors 2008, 8(1), 327-346; doi:10.3390/s8010327
Received: 23 November 2007 / Accepted: 15 January 2008 / Published: 21 January 2008
Cited by 68 | PDF Full-text (900 KB) | HTML Full-text | XML Full-text
Abstract
Piezoelectric ceramic Lead Zirconate Titanate (PZT) based electro-mechanicalimpedance (EMI) technique for structural health monitoring (SHM) has been successfullyapplied to various engineering systems. However, fundamental research work on thesensitivity of the PZT impedance sensors for damage detection is still in need. In thetraditional EMI
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Piezoelectric ceramic Lead Zirconate Titanate (PZT) based electro-mechanicalimpedance (EMI) technique for structural health monitoring (SHM) has been successfullyapplied to various engineering systems. However, fundamental research work on thesensitivity of the PZT impedance sensors for damage detection is still in need. In thetraditional EMI method, the PZT electro-mechanical (EM) admittance (inverse of theimpedance) is used as damage indicator, which is difficult to specify the effect of damage onstructural properties. This paper uses the structural mechanical impedance (SMI) extractedfrom the PZT EM admittance signature as the damage indicator. A comparison study on thesensitivity of the EM admittance and the structural mechanical impedance to the damages ina concrete structure is conducted. Results show that the SMI is more sensitive to the damagethan the EM admittance thus a better indicator for damage detection. Furthermore, this paperproposes a dynamic system consisting of a number of single-degree-of-freedom elementswith mass, spring and damper components to model the SMI. A genetic algorithm isemployed to search for the optimal value of the unknown parameters in the dynamic system.An experiment is carried out on a two-storey concrete frame subjected to base vibrations thatsimulate earthquake. A number of PZT sensors are regularly arrayed and bonded to the framestructure to acquire PZT EM admittance signatures. The relationship between the damageindex and the distance of the PZT sensor from the damage is studied. Consequently, thesensitivity of the PZT sensors is discussed and their sensing region in concrete is derived. Full article
(This article belongs to the Special Issue Sensors for Urban Environmental Monitoring)
Open AccessArticle Use of a Dynamic Enclosure Approach to Test the Accuracy of the NDIR Sensor: Evaluation Based on the CO2 Equilibration Pattern
Sensors 2007, 7(12), 3459-3471; doi:10.3390/s7123459
Received: 7 November 2007 / Accepted: 19 December 2007 / Published: 20 December 2007
Cited by 3 | PDF Full-text (351 KB) | HTML Full-text | XML Full-text
Abstract
As part of a quality assurance (QA) study for sensor systems, an enclosureapproach is applied to assess the accuracy of non-dispersive infrared (NDIR)-based CO2sensors. To examine the performance of the sensor system, an enclosure chambercontaining six sensor units of the two
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As part of a quality assurance (QA) study for sensor systems, an enclosureapproach is applied to assess the accuracy of non-dispersive infrared (NDIR)-based CO2sensors. To examine the performance of the sensor system, an enclosure chambercontaining six sensor units of the two model types (B-530 and H-500) was equilibratedwith calibrated CO2 standards at varying concentration levels. Initially, the equilibrationpattern was analyzed by CO2-free gas (0 ppm) at varying flow rates (i.e., 100, 200, 500, and1000 mL min-1). Results of the test yielded a highly predictable and quantifiable empiricalrelationship as a function of such parameters as CO2 concentration, flow rate, andequilibration time for the enclosure system. Hence, when the performance of the NDIR-method was evaluated at other concentrations (i.e., 500 and 1000 ppm), all the sensor unitsshowed an excellent compatibility, at least in terms of the correlation coefficients (r >0.999, p = 0.01). According to our analysis, the NDIR sensor system seems to attain anoverall accuracy near the 5% level. The relative performance of the NDIR sensor for CO2analysis is hence comparable with (or superior to) other methods previously investigated.The overall results of this study indicate that NDIR sensors can be used to provide highlyaccurate and precise analyses of CO2 both in absolute and relative terms. Full article
(This article belongs to the Special Issue Sensors for Urban Environmental Monitoring)
Open AccessArticle Object-Based Classification of Ikonos Imagery for Mapping Large-Scale Vegetation Communities in Urban Areas
Sensors 2007, 7(11), 2860-2880; doi:10.3390/s7112860
Received: 13 September 2007 / Accepted: 19 November 2007 / Published: 20 November 2007
Cited by 53 | PDF Full-text (1045 KB) | HTML Full-text | XML Full-text
Abstract
Effective assessment of biodiversity in cities requires detailed vegetation maps.To date, most remote sensing of urban vegetation has focused on thematically coarse landcover products. Detailed habitat maps are created by manual interpretation of aerialphotographs, but this is time consuming and costly at large
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Effective assessment of biodiversity in cities requires detailed vegetation maps.To date, most remote sensing of urban vegetation has focused on thematically coarse landcover products. Detailed habitat maps are created by manual interpretation of aerialphotographs, but this is time consuming and costly at large scale. To address this issue, wetested the effectiveness of object-based classifications that use automated imagesegmentation to extract meaningful ground features from imagery. We applied thesetechniques to very high resolution multispectral Ikonos images to produce vegetationcommunity maps in Dunedin City, New Zealand. An Ikonos image was orthorectified and amulti-scale segmentation algorithm used to produce a hierarchical network of image objects.The upper level included four coarse strata: industrial/commercial (commercial buildings),residential (houses and backyard private gardens), vegetation (vegetation patches larger than0.8/1ha), and water. We focused on the vegetation stratum that was segmented at moredetailed level to extract and classify fifteen classes of vegetation communities. The firstclassification yielded a moderate overall classification accuracy (64%, κ = 0.52), which ledus to consider a simplified classification with ten vegetation classes. The overallclassification accuracy from the simplified classification was 77% with a κ value close tothe excellent range (κ = 0.74). These results compared favourably with similar studies inother environments. We conclude that this approach does not provide maps as detailed as those produced by manually interpreting aerial photographs, but it can still extract ecologically significant classes. It is an efficient way to generate accurate and detailed maps in significantly shorter time. The final map accuracy could be improved by integrating segmentation, automated and manual classification in the mapping process, especially when considering important vegetation classes with limited spectral contrast. Full article
(This article belongs to the Special Issue Sensors for Urban Environmental Monitoring)
Open AccessArticle Tempo-Spatial Patterns of Land Use Changes and Urban Development in Globalizing China: A Study of Beijing
Sensors 2007, 7(11), 2881-2906; doi:10.3390/S7112881
Received: 5 November 2007 / Accepted: 19 November 2007 / Published: 20 November 2007
Cited by 29 | PDF Full-text (2676 KB) | HTML Full-text | XML Full-text
Abstract
This study examines the temporal and spatial changes in land use as aconsequence of rapid urban development in the city of Beijing. Using a combination oftechniques of remote sensing and GIS, the study identifies a substantial loss of plaindryland and a phenomenal expansion
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This study examines the temporal and spatial changes in land use as aconsequence of rapid urban development in the city of Beijing. Using a combination oftechniques of remote sensing and GIS, the study identifies a substantial loss of plaindryland and a phenomenal expansion of urban construction land over the recent decade.Geographically, there is a clear shifting of urban construction land from the inner city tothe outskirts as a consequence of suburbanization. The outward expansion of the ring-roadsystem is found to be one of the most important driving forces explaining the temporal andspatial pattern of land use change. The uneven distribution of population stands as anotherfactor with significant correlation with land use change. The application of the techniquesof remote sensing and GIS can enhance the precision and comparability of research onland use change and urban transformation in China. Full article
(This article belongs to the Special Issue Sensors for Urban Environmental Monitoring)
Open AccessArticle High-rise Buildings versus Outdoor Thermal Environment in Chongqing
Sensors 2007, 7(10), 2183-2200; doi:10.3390/s7102183
Received: 30 July 2007 / Accepted: 27 September 2007 / Published: 11 October 2007
PDF Full-text (1213 KB) | HTML Full-text | XML Full-text
Abstract
This paper gives a brief description of the over quick urbanization sinceChongqing, one of the biggest cities in China, has been a municipality directly under theCentral Government in 1997, excessive development and exceeding increase of high-risebuildings because of its special geographical position which
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This paper gives a brief description of the over quick urbanization sinceChongqing, one of the biggest cities in China, has been a municipality directly under theCentral Government in 1997, excessive development and exceeding increase of high-risebuildings because of its special geographical position which finally leads to the worseningof the urban outdoor thermal environment. Then, this paper makes a bright balance to thefield measurement and simulated results of the wind speed field, temperature field of onemultifunctional high-rise building in Chongqing university located in the city center, andthe contrasted results validate the correctness of CFD in the outdoor thermal environmentalsimulation, expose the disadvantages of high-rise buildings on the aspects of blocking thewind field, decreasing wind speed which results in accumulation of the air-conditioningheat revolving around and periscian region where sunshine can not rip into. Finally, inorder to improve the urban outdoor thermal environment near the high-rise buildingsespecially for the angle of natural ventilation, this paper simulates the wind environment indifferent architectural compositions and architectural layouts by CFD, and the simulatedresults show that freestyle and tower buildings which can guarantee the wind speed andtake the air-conditioning heat away are much suitable and reasonable for the specialChongqing geography. These conclusions can also be used as a reference in othermountain cities, especially for the one with a great number of populations. Full article
(This article belongs to the Special Issue Sensors for Urban Environmental Monitoring)
Open AccessArticle Land Use and Land Cover Change in Guangzhou, China, from 1998 to 2003, Based on Landsat TM /ETM+ Imagery
Sensors 2007, 7(7), 1323-1342; doi:10.3390/s7071323
Received: 29 June 2007 / Accepted: 24 July 2007 / Published: 25 July 2007
Cited by 42 | PDF Full-text (1691 KB) | HTML Full-text | XML Full-text
Abstract
Land use and land cover change is a major issue in global environment change,and is especially significant in rapidly developing regions in the world. With its economicdevelopment, population growth, and urbanization, Guangzhou, a major metropolitan inSouth China, have experienced a dramatic land use
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Land use and land cover change is a major issue in global environment change,and is especially significant in rapidly developing regions in the world. With its economicdevelopment, population growth, and urbanization, Guangzhou, a major metropolitan inSouth China, have experienced a dramatic land use and land cover (LULC) change over thepast 30 years. Fast LULC change have resulted in degradation of its ecosystems andaffected adversely the environment. It is urgently needed to monitor its LULC changes andto analyses the consequences of these changes in order to provide information for policy-makers to support sustainable development. This study employed two Landsat TM/ETM images in the dry season to detect LULC patterns in 1998 and 2003, and to examine LULCchanges during the period from 1998 to 2003. The type, rate, and pattern of the changesamong five counties of Guangzhou Municipality were analyzed in details by post-classification method. LULC conversion matrix was produced for each county in order toexplore and explain the urban expansion and cropland loss, the most significant types ofLULC change. Land use conversion matrixes of five counties were discussed respectivelyin order to explore and explain the inherence of land use change. The results showed thaturban expansion in these five counties kept an even rate of increase, while substantialamount of cropland vanished during the period. It is also noted that the conversion between cropland and orchard land was intensive. Forest land became the main source of new croplands. Full article
(This article belongs to the Special Issue Sensors for Urban Environmental Monitoring)

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