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Search Results: 1 - 10 of 16593 matches for " Change Detection "
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Monitoring and Change Detection along the Eastern Side of Qena Bend, Nile Valley, Egypt Using GIS and Remote Sensing  [PDF]
Ahmed Omar Abd El-Aziz
Advances in Remote Sensing (ARS) , 2013, DOI: 10.4236/ars.2013.23030

This Article is set to track and monitor changes through spatial dependence of remote sensing data and GIS analysis, the suggested working method in this research is by sub pixel classification techniques. Change detection is a central task for land cover monitoring by remote sensing. It uses multi temporal image data sets in order to detect land cover changes from spectral discrepancies [1] (Rafael, et al.). It discusses the study perception of the situation in the past as well as the current and finally the future status of changes that land uses in Eastern Qena meander specifically in places of estuary floods, and the most important estuary leading to Qena, and whether these changes in land are used in direction of the mouth of the stream or not, especially that when it happened before, it caused destruction of both activities, urban & agricultural land. It will rely on Landsat images in years of (1972-2012), conduct analysis, different classifications integration with geographic information systems (GIS), and field as well as samples for the accuracy assessment.

Change Analysis of Land Use and Urban Growth in the Municipalities of Culiacan and Navolato, Sinaloa, Mexico Using Statistical Techniques and GIS  [PDF]
Geovanna Gpe Hinojoza Castro, Wenseslao Plata Rocha
Journal of Geographic Information System (JGIS) , 2015, DOI: 10.4236/jgis.2015.76050
Abstract: Previous analysis of land use and land cover changes help us to understand the range, importance and effects that this dynamic has in the environment and its relation with the human’s activities. This work consists in analyzing the land use/cover for the Municipalities of Culiacan and Navolato, Mexico, through statistical techniques and Geographic Information Systems. The methodology is allowed to determine the changes, gains, losses and transitions in the different categories in the period studied. The results show significant changes in the denominate categories, agriculture and forest. However, the greatest change is the increase of the urban areas. The knowledge in the studied area and its dynamics are carried out and this work serves as a reference to study, manage and plan for our territory.
Sequential Tests for the Detection of Voice Activity and the Recognition of Cyber Exploits  [PDF]
Ehab Etellisi, P. Papantoni-Kazakos
Communications and Network (CN) , 2011, DOI: 10.4236/cn.2011.34022
Abstract: We consider the problem of automated voice activity detection (VAD), in the presence of noise. To attain this objective, we introduce a Sequential Detection of Change Test (SDCT), designed at the independent mixture of Laplacian and Gaussian distributions. We analyse and numerically evaluate the proposed test for various noisy environments. In addition, we address the problem of effectively recognizing the possible presence of cyber exploits in the voice transmission channel. We then introduce another sequential test, designed to detect rapidly and accurately the presence of such exploits, named Cyber Attacks Sequential Detection of Change Test (CA-SDCT). We analyse and numerically evaluate the latter test. Experimental results and comparisons with other proposed methods are also presented.
Monitoring Forests: A New Paradigm of Remote Sensing & GIS Based Change Detection  [PDF]
Subhash Ashutosh
Journal of Geographic Information System (JGIS) , 2012, DOI: 10.4236/jgis.2012.45051
Abstract: Remote sensing has emerged as the main tool for mapping and monitoring of forest resources globally. In India, this technological tool is in use for biennial monitoring of forest cover of the country for the last 25 years. Among the numerous applications of remote sensing in forest management, change detection is the one which is most frequently used. In this paper, a new paradigm of change detection has been presented in which change of vegetation in a grid (a square shaped unit area) is the basis of change analysis instead of change at the pixel level. The new method is a simpler approach and offers several advantages over the conventional approaches of remote sensing based change detection. The study introduces an index termed as ‘Grid Vegetation Change Index (GVCI)’, its numerical value gives quantified assessment of the degree of change. The minus value of GVCI indicates loss or negative change and similarly positive value vice versa. By applying the GVCI on a pair of remotely sensed images of two dates of an area, one can know degree of vegetation change in every unit area (grid) of the large landscape. Based on the GVCI values, one can select those grids which show significant changes. Such ‘candidate grids with significant changes’ may be shortlisted for ground verification and studying the causes of change. Since the change identification is based on the index value, it is free from human subjectivity or bias. Though there may be some limitations of the methodology, the GVCI based approach offers an operational application for monitoring forests in India and elsewhere for complete scanning of forest areas to pointedly identify change locations, identifying the grids with significant changes for objective and discrete field inspections with the help of GPS. It also offers a method to monitor progress of afforestation and conservation schemes, monitor habitats of wildlife areas and potential application in carbon assessment methodologies of CDM and REDD+.
Spatio-Temporal Land Cover Dynamics in Open Cast Coal Mine Area of Singrauli, M.P., India  [PDF]
Imran Khan, Akram Javed
Journal of Geographic Information System (JGIS) , 2012, DOI: 10.4236/jgis.2012.46057
Abstract: Singrauli is an opencast coal mining area where large scale mining activities are going on continuously, land use/land cover studies are of vital importance to observe the changes in the land use/land cover. The present study utilizes multi-spectral/multi-temporal data of Indian Remote Sensing Satellite (IRS) LISS II geocoded (FCC) of 4th May 1993 and LISS III of 4th May 2010 for thematic mapping. Survey of India toposheet 63L/12 on scale 1:50,000 were used for preparation of base map which was overlaid on the FCC for land use/land cover mapping through visual interpretation. Visual interpretation of satellite imagery led to the identification of 15 land use/land cover categories such as dense forest, open forest, open scrub, plantation, cultivated land, uncultivated land, mining pit, overburden dumps, wasteland and settlement. The ground truth verification was carried out in key areas to rectify the errors in generated maps and then land use/land cover maps were finalized. The comparative analysis of land use/land cover shows that dense forest has been degraded to open forest, open scrubs and mining pits due to the expansion of mining activity. Open scrubs has increased, overburden dumps has increased, settlement has also increased, cultivated land has decreased and changed into uncultivated land and wasteland. It has also been observed that the plantation has been done on overburden dumps and residential colonies of NCL and NTPC. It has been identified that the main drivers which has increased the rate of change in land use/land cover are mainly coal mining activities and industrial expansion.
Change Detection of Rice Cultivation in Bangladesh Based on the Phenological Analysis of MODIS Data  [PDF]
Tarulata Shapla, Jonggeol Park, Chiharu Hongo, Hiroaki Kuze
Advances in Remote Sensing (ARS) , 2015, DOI: 10.4236/ars.2015.44026
Abstract: Mapping rice cultivation is indispensable for monitoring food supply conditions in Bangladesh because of the economical importance of the crop for supporting ever increasing population in the country. In this paper, we extract the rice paddy field using the MODIS satellite data for five districts of Pabna, Manikganj, Sherpur, Sylhet, and Gazipur, each of which is characterized with its own aspects in terms of rice cultivation. Land classification is implemented using the vegetation index information derived from the red (band 1) and near-infrared (band 2) bands of MODIS 8-day composite time series data for the two time periods of 2001-2003 and 2011-2013. Results of unsupervised classification indicate that the paddy area coverage increased about 4% and 1% in Gazipur and Sylhet, respectively. In Pabna, Manikganj, and Sherpur, on the other hand, paddy area decreased by 10%, 2% and 5%, respectively, whereas notable increase of 12%, 2% and 7% was found in homestead area coverage, which is becoming more and more important for better management of small-scale agroforestry. At the same time, in Sherpur and Sylhet, forest area increased by 1% and 2% over the same time period. As a validation of these results, the changes detected in Gazipur are compared with those previously derived from the analysis of Landsat data with higher spatial resolution of 30 m as compared with that of MODIS (250 m). Also, the seasonal rice cropping pattern is studied in these five districts for discriminating cultivated rice types. These changes suggest that as a whole, efforts are being made to increase the food production, though the influence of population pressure and economic growth is apparent in these regions.
Monitoring Restoration of the Eastern Usangu Wetland by Assessment of Land Use and Cover Changes  [PDF]
Emiliana John Mwita
Advances in Remote Sensing (ARS) , 2016, DOI: 10.4236/ars.2016.52012
Abstract: Conflicting interests in the use and management of wetlands have always resulted in their degradation. The degradation of wetlands affects their natural functioning, environmental health and livelihood of the people who depend on them. The eastern Usangu wetland has suffered a lot from multiple-use pressure arising from both national and local interests. As a result, the government banned the use of the wetland in 2006 to support its restoration process. The aim of the current study was to assess the restoration process of the eastern Usangu wetland using time-series Landsat images over a 20-year period, from 1995 to 2015. Cross-tabulation of composite NDVI images was used to examine the changes. The results indicate that the land cover declined by 20% between 1995 and 2005, and increased by more than 25% between 2005 and 2015. The size of the permanent swamp increased consistently, by more than 15% between 1995 and 2015. Wetland use has declined to about 15% over the 20 years. Wetland restoration seems to be a slow process that depends on multiple factors. It thus is important that wetlands are managed well for sustained benefits, rather than waiting to rescue them in a crisis. The well-being of the people depending on the wetlands should be considered when implementing measures to protect the wetlands. Awareness creation among the users, diversification of sources of income and enforcement of the laws and policies governing the use of wetlands by the government may improve status of wetlands.
A Weld Defects Detection System Based on a Spectrometer
Daniel Bebiano,Sadek C. A. Alfaro
Sensors , 2009, DOI: 10.3390/s90402851
Abstract: Improved product quality and production methods, and decreased production costs are important objectives of industries. Welding processes are part of this goal. There are many studies about monitoring and controlling welding process. This work presents a non-intrusive on-line monitoriment system and some algorithms capable of detecting GTAW weld defects. Some experiments were made to simulate weld defects by disturbing the electric arc. The data comes from a spectrometer which captures perturbations on the electric arc by the radiation emission of chosen lines. Algorithms based on change detection methods are used to indicate the presence and localization of those defects.
Land Cover Classification and Forest Change Analysis, Using Satellite Imagery-A Case Study in Dehdez Area of Zagros Mountain in Iran  [PDF]
Ali Asghar Torahi, Suresh Chand Rai
Journal of Geographic Information System (JGIS) , 2011, DOI: 10.4236/jgis.2011.31001
Abstract: The importance of accurate and timely information describing the nature and extent of land resources and changes over time is increasing, especially in mountainous areas. We have developed a methodology to map and monitor land cover change using multitemporal Landsat Thematic Mapper (TM) and ASTER data in Zagros mountains of Iran for 1990, 1998, and 2006.Land-use/cover mapping is achieved through interpreta-tion of Landsat TM satellite images of 1990, 1998 and TERRA-ASTER image of 2006 using ENVI 4.3. Based on the Anderson land-use/cover classification system, the land-use and land-covers are classified as forest land, rangeland, water bodies, agricultural land and residential land. The unsupervised image classifi-cation method carried out prior to field visit, in order to determine strata for ground truth. Fieldwork carried out to collect data for training and validating land-use/cover interpretation from satellite image of 2006, and for qualitative description of the characteristics of each land-use/cover class. The land-use/cover maps of 1990, 1998 and 2006 were produced by using supervised image classification technique based on the Maxi-mum Likelihood Classifier (MLC) and 132 training samples. Error matrices as cross-tabulations of the mapped class vs. the reference class were used to assess classification accuracy. Overall accuracy, user’s and producer’s accuracies, and the Kappa statistic were then derived from the error matrices. A multi-date post-classification comparison change detection algorithm was used to determine changes in land cover in three intervals, 1990–1998, 1998–2006 and 1990–2006. To evaluate the change maps for the 1990 to 2006 interval, we randomly sampled the areas that classified as change and no-change and determined whether they were correctly classified. The maps showed that between 1990 and 2006 the amount of forest land de-creased from 67% to 38.5% of the total area, while rangelands, agriculture, settlement and surface water in-creased from 30.8% to 45%, 1.2% to 7.0%, 0.3% to 7.5% and 0.6% to 1.8%, respectively. The area was dominated by 35.9%, 28.9% and 29.3% dense forest, 42.2%, 46.4% and 43.2% open forest and 21.9%, 24.8% and 27.5% degraded forest in 1990, 1998 and 2006, respectively. During 16 years span period (1990-2006) about 10170.3 ha, 2963.4 ha, 351.7 ha and 3039.2 ha of forest lands were converted to range-land, agriculture, water body and settlement. The overall five-class classification accuracies averaged 78.6% for the three years. The overall accuracy of land cover change maps, generated from
Land Use and Land Cover Changes of West Tahta Region, Sohag Governorate, Upper Egypt  [PDF]
Ismail Esam, Faid Abdalla, Niesner Erich
Journal of Geographic Information System (JGIS) , 2012, DOI: 10.4236/jgis.2012.46053
Abstract: Due to the growing of population in Egypt during the last few decades, great changes in agricultural area, and urbanization of Egypt art occurred. In this study we utilized the available record of multitemporal Land sat Thematic Mapper (Tm) and Egyptsat image to produce land cover/land use map of the area between 1987 and 2009. Also we used the post-classification change detection analysis to detect the change in the agriculture, urban areas and the change in the River Nile during the period between 1987 and 2009. The post-classification change detection analysis shows that agriculture development increased by 1785.96 Hectare through the study period with average annual rate of land reclamation 81.18 Hectare/year. While the urban area increased by 2231.24 Hectare with average annual rate 101.42 Hectare/ year the increase of the urbanization and the growth occurring through encroachment into the farmer old cultivated lands. The change in the River Nile is not so much is reached to 138.32 hectare in the study period with average annual rate 6.29 Hectare/year. The result of this study show that, the accuracy are quantify with the land cover changes and also delineate their spatial patterns, which display the efficiency of land sat in evaluating landscape dynamics over a particular time span. This data are very useful for natural resources management.
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