Identification of destructed building and land use change in the post-tsunami disaster with a quick look images of IKONOS and Quickbird (A Case Study in Meulaboh City) Wikantika, K., Sinaga, A., Hadi, F., Melissa, Darmawan, S. Expertise Group on Remote Sensing and Geographical Information Science (ReSGIS) Geodetic Engineering and Geomatic Program Institute of Technology Bandung Abstract Tsunami is a series of high waves which is caused by the movement of massive mass of sea water. Tsunami disaster is one of the earth's phenomenon that can not be avoided by human being. Even though, tsunami disaster still can be learned and its impact to humankind and their environment. Remote sensing technology is one of the alternative technologies to extract spatial information on tsunami disaster where it can be utilized to help the planning and reconstruction process in the tsunami impacted region. This study aims to know how far the remote sensing technology can contribute to the tsunami mitigation process. The results obtained from this study are information about destructed buildings, land use change and total coverage of land affected by tsunami in Nangroe Aceh Darussalam (NAD) with Meulaboh City as a case study. INTRODUCTION Tragedy of Tsunami on 26 December 2004, which strikes some countries in Asia, including Indonesia, had brought big impact for society and environment. For example, Tsunami had caused Nanggroe Aceh Darussalam (NAD) to lose more than one hundred thousand of its people and had produced financial lost some quintillion rupiahs. Beside that, these disasters have also destructed the environment, plants and infrastructure of NAD which need enormous costs and efforts to reconstruct (Kompas, 2005). During the initial stage of reconstruction phase, it is important to know how far are the infra-structural and environmental damage in NAD, so a planning development of NAD's infrastructure is probably planned better. To fulfill this purpose, we need to observe and identify the area knocked over by Tsunami which is consisted of several processes such as the identification of land cover change, houses before and after tsunami and the identification of wide area before and after tsunami. Thereby we also can calculate the expense to be required in redevelopment NAD's infrastructure. To identify this, we need a technology which can give the information quickly and accurately. One of technology that can be used in this case is remote sensing technology. Currently, this technology grow very rapidly and surely with the appearance of remote sensing technology satellite which have high resolution, will help us in getting information on certain object or area. The remote sensing data which has the high resolution are Quickbird and IKONOS images (www.infoterra-global.com/quickbird.htm). Quickbird and IKONOS satellite images has the resolution sub-meter, so it is very usable in detecting houses and other objects and resident like streets and rivers. The aim of this study is to provide quick assessment method to identify land cover changes and destructed buildings in Meulaboh city using a quick look images of Quickbird and IKONOS data. This is needed to assess quickly impacts of tsunami on land cover and damaged building in affected areas. METHODS Basically, the study comprises of several stages, they are pre processing, on screen digitizing, data conversion and spatial analysis, finally visualization of destrcuted building and land cover changes on thematic map. The methodology of the study is shown by Figure 1 below. Firstly, we process a quicklook data of Quickbird and IKONOS images through geometric correction. This process includes ground check point (GCP) selection that obtained from topographic map over the study area. Then the image of Quickbird is rectified using polynomial method (Jensen, 1986). IKONOS image is registered using corrected Quickbird image. Both corrected Quickbird and IKONOS images then used as input data for digitizing land cover categories and buildings in Meulaboh City. With these vector-based land cover and building features, the changes of land cover and buildings before and after tsunami disaster is analyzed. Finally, the thematic maps displaying land cover and buildings over the study area, before and after tsunami disaster are generated. .  Figure 1. Methodology of the study RESULTS Topographic map at scale of 1 : 50,000 was used to collect GCP over the study area. The GCPs were chosen, most of them being road intersections and buildings, which were easily identifiable in the image. The highest root mean square error (RMSE) of geometric correction of Quickbird image is 0.63 pixel while the lowest value is equal to 0.05 pixel. Actually, topographic map at scale of 1 : 50,000 is not compatible for rectifying very high satellite image such as Quickbird and IKONOS images. This is done because of the output of the study is used for quick assessment only in relation to land cover change and identification of destructed buildings. Identification of land cover categories (road, shoreline, river, vegetation, paddy field etc.) and buildings is carried out visually. These objects are digitized using GIS software. The thematic maps of land cover and building before and after tsunami disaster shown in Figure 2 and 3, respectively.  Figure 2. Land cover and buildings map of Meulaboh city before tsunami disaster  Figure 3. Land cover and buildings map of Meulaboh city after tsunami disaster Spatial analysis shows that there are significant changes of land cover and buildings in Meulaboh city before and after tsunami disaster. Tabel 1 shows changes of land cover and buildings before and after tsunami.  From Table 1 above we can calculate land cover change and amoutn of damaged buildings after tsunami disaster :
CONCLUSIONS
Acknowledgement
References
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