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Evaluation of the capabilities of satellite images alsat 2-a for emergency mapping in urban areas, case of the city of m’sila (Algeria)

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Abstract

In this paper, we will show the capabilities and limitations of Alsat-2 images in mapping urban areas in emergency situation. The aim of the research was to provide urban information that is geo-referenced in real time during natural disasters (floods, earthquakes). It’s important for fast decision-making so that they will be a necessary support for the estimation of the damages.The following study tests the spatial and radiometric quality of Alsat 2-A images and proposes technical solutions for theiruse in urban mapping. In order to identify and extract the ground realities, we shall describe and make an effort to discern the perceptible aspects of features in urban area. The adopted methodology carries out a statistical analysis of the information extracted from Alsat-2 images of the studied area (the city of M’Sila, Algeria) using classification and segmentation methods. The statistics will show the percentage of the area in relation to the total size of geometric surface and the distance for linear objects. As a result, the quality of the extracted urban texture necessary for urban mapping will be determined. Image processing to improve resolution quality was carried out using merging method. However, the analysis of consistency and discrepancy of these statistics will be done by comparing samples of field data using confusion matrix.

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Starting with a group of very different cities from the same cultural region, latin America, a team of young social scientists, thanks to satellite images, obtain a great deal of original material on urban land use and the spatial transformation of the peri-urban area to integrate it with other data for research for a PHD in social sciencis with the objectif of being operational.
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With the rapid development of remote sensing, digital image processing has become an important tool for the quantitative and statistical analysis of remotely sensed images. These images most often contain complex natural scenes. The robust interpretation of such images requires the use of different sources of information about the scenes under consideration. This paper presents an integrated approach to robust analysis of SPOT images with the aid of map information as well as a priori knowledge about the contextual information of images. Markov random field theory and the Bayes formula are used to formulate the image analysis problem as a problem of optimization of an objective function, which in turn permits the application of various existing optimization algorithms to solve the problem. To increase the robustness of the result, several techniques are proposed to effectively use map information and image contextual information. The first one is concerned with the estimation of the parameters in the objective function with the help of these two sources of information. The second one is the integration of map information in Bayes image modeling using a Markov random field. The third one is a new optimization algorithm which takes into account map information and image contextual information by means of a feedback control scheme. The last technique proposed to increase the robustness of the result is concerned with the fusion of several (intermediate) analysis results by again using map knowledge and image contextual information for the estimation of the reliability of these results
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Automatic road extraction based on local histogram and support vector data description classifier from very high resolution digital aerial
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